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* [moderation/CI] Re: Data in direntry (dirdata) feature
@ 2026-04-18  2:04 syzbot ci
  2026-04-18  6:45 ` Aleksandr Nogikh
  0 siblings, 1 reply; 6+ messages in thread
From: syzbot ci @ 2026-04-18  2:04 UTC (permalink / raw)
  To: syzkaller-upstream-moderation; +Cc: syzbot

syzbot ci has tested the following series

[v1] Data in direntry (dirdata) feature
https://lore.kernel.org/all/20260417213723.74204-1-artem.blagodarenko@gmail.com
* [PATCH 1/3] ext4: make dirdata work with metadata_csum
* [PATCH 2/3] ext4: add dirdata support structures and helpers
* [PATCH 3/3] ext4: dirdata feature

and found the following issues:
* KASAN: slab-out-of-bounds Read in __ext4_check_dir_entry
* KASAN: slab-out-of-bounds Read in dx_probe
* KASAN: slab-use-after-free Read in __ext4_check_dir_entry
* KASAN: slab-use-after-free Read in dx_probe
* KASAN: use-after-free Read in __ext4_check_dir_entry

Full report is available here:
https://ci.syzbot.org/series/590e846e-42c0-4497-b6ae-b95ed4468941

***

KASAN: slab-out-of-bounds Read in __ext4_check_dir_entry

tree:      torvalds
URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux
base:      70b672833f4025341c11b22c7f83778a5cd611bc
arch:      amd64
compiler:  Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
config:    https://ci.syzbot.org/builds/7b860156-1ca9-441f-b899-ebfb5a09620d/config
syz repro: https://ci.syzbot.org/findings/d27eccd2-4663-4047-abb9-9c24cb32f887/syz_repro

loop0: lost filesystem error report for type 5 error -117
EXT4-fs (loop0): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: none.
==================================================================
BUG: KASAN: slab-out-of-bounds in ext4_dirent_get_data_len fs/ext4/ext4.h:4040 [inline]
BUG: KASAN: slab-out-of-bounds in ext4_dir_entry_len fs/ext4/ext4.h:4060 [inline]
BUG: KASAN: slab-out-of-bounds in __ext4_check_dir_entry+0x527/0xa70 fs/ext4/dir.c:96
Read of size 1 at addr ffff8881090bfe5c by task syz.0.20/5967

CPU: 1 UID: 0 PID: 5967 Comm: syz.0.20 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xba/0x230 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 ext4_dirent_get_data_len fs/ext4/ext4.h:4040 [inline]
 ext4_dir_entry_len fs/ext4/ext4.h:4060 [inline]
 __ext4_check_dir_entry+0x527/0xa70 fs/ext4/dir.c:96
 ext4_inlinedir_to_tree+0x6be/0xbf0 fs/ext4/inline.c:1322
 ext4_htree_fill_tree+0x50b/0x1230 fs/ext4/namei.c:1184
 ext4_dx_readdir fs/ext4/dir.c:600 [inline]
 ext4_readdir+0x2f7b/0x3870 fs/ext4/dir.c:146
 iterate_dir+0x399/0x570 fs/readdir.c:108
 __do_sys_getdents64 fs/readdir.c:412 [inline]
 __se_sys_getdents64+0xf1/0x280 fs/readdir.c:397
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe47219c819
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fe4730c0028 EFLAGS: 00000246 ORIG_RAX: 00000000000000d9
RAX: ffffffffffffffda RBX: 00007fe472415fa0 RCX: 00007fe47219c819
RDX: 000000000000ff80 RSI: 9999999999999999 RDI: 0000000000000004
RBP: 00007fe472232c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe472416038 R14: 00007fe472415fa0 R15: 00007ffff595c618
 </TASK>

Allocated by task 5967:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __do_kmalloc_node mm/slub.c:5260 [inline]
 __kmalloc_noprof+0x35c/0x760 mm/slub.c:5272
 kmalloc_noprof include/linux/slab.h:954 [inline]
 ext4_mb_init+0x15d/0x2ad0 fs/ext4/mballoc.c:3729
 __ext4_fill_super fs/ext4/super.c:5623 [inline]
 ext4_fill_super+0x5647/0x6320 fs/ext4/super.c:5793
 get_tree_bdev_flags+0x431/0x4f0 fs/super.c:1694
 vfs_get_tree+0x92/0x2a0 fs/super.c:1754
 fc_mount fs/namespace.c:1193 [inline]
 do_new_mount_fc fs/namespace.c:3763 [inline]
 do_new_mount+0x341/0xd30 fs/namespace.c:3839
 do_mount fs/namespace.c:4172 [inline]
 __do_sys_mount fs/namespace.c:4361 [inline]
 __se_sys_mount+0x31d/0x420 fs/namespace.c:4338
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff8881090bfe00
 which belongs to the cache kmalloc-64 of size 64
The buggy address is located 44 bytes to the right of
 allocated 48-byte region [ffff8881090bfe00, ffff8881090bfe30)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1090bf
flags: 0x17ff00000000000(node=0|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 017ff00000000000 ffff8881000418c0 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800200020 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 16414655371, free_ts 15537272896
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x231/0x280 mm/page_alloc.c:1889
 prep_new_page mm/page_alloc.c:1897 [inline]
 get_page_from_freelist+0x24dc/0x2580 mm/page_alloc.c:3962
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5250
 alloc_slab_page mm/slub.c:3292 [inline]
 allocate_slab+0x77/0x660 mm/slub.c:3481
 new_slab mm/slub.c:3539 [inline]
 refill_objects+0x331/0x3c0 mm/slub.c:7175
 refill_sheaf mm/slub.c:2812 [inline]
 __pcs_replace_empty_main+0x2e6/0x730 mm/slub.c:4615
 alloc_from_pcs mm/slub.c:4717 [inline]
 slab_alloc_node mm/slub.c:4851 [inline]
 __do_kmalloc_node mm/slub.c:5259 [inline]
 __kmalloc_noprof+0x474/0x760 mm/slub.c:5272
 kmalloc_noprof include/linux/slab.h:954 [inline]
 kzalloc_noprof include/linux/slab.h:1188 [inline]
 kobject_get_path+0xc5/0x2f0 lib/kobject.c:161
 kobject_uevent_env+0x2a1/0x9e0 lib/kobject_uevent.c:545
 really_probe+0x789/0xaf0 drivers/base/dd.c:771
 __driver_probe_device+0x18c/0x320 drivers/base/dd.c:863
 driver_probe_device+0x4f/0x240 drivers/base/dd.c:893
 __device_attach_driver+0x279/0x430 drivers/base/dd.c:1021
 bus_for_each_drv+0x258/0x2f0 drivers/base/bus.c:500
 __device_attach+0x2c5/0x450 drivers/base/dd.c:1093
 device_initial_probe+0xa1/0xd0 drivers/base/dd.c:1148
page last free pid 33 tgid 33 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1433 [inline]
 __free_frozen_pages+0xc2b/0xdb0 mm/page_alloc.c:2978
 vfree+0x25a/0x400 mm/vmalloc.c:3479
 delayed_vfree_work+0x55/0x80 mm/vmalloc.c:3398
 process_one_work kernel/workqueue.c:3276 [inline]
 process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Memory state around the buggy address:
 ffff8881090bfd00: 00 00 00 00 00 00 00 04 fc fc fc fc fc fc fc fc
 ffff8881090bfd80: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
>ffff8881090bfe00: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc
                                                    ^
 ffff8881090bfe80: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff8881090bff00: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc
==================================================================


***

KASAN: slab-out-of-bounds Read in dx_probe

tree:      torvalds
URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux
base:      70b672833f4025341c11b22c7f83778a5cd611bc
arch:      amd64
compiler:  Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
config:    https://ci.syzbot.org/builds/7b860156-1ca9-441f-b899-ebfb5a09620d/config
syz repro: https://ci.syzbot.org/findings/a5fcf3bd-f1ae-4b81-b5d2-f96899ea7690/syz_repro

==================================================================
BUG: KASAN: slab-out-of-bounds in ext4_dir_entry_is_tail fs/ext4/ext4.h:4001 [inline]
BUG: KASAN: slab-out-of-bounds in ext4_dirent_get_data_len fs/ext4/ext4.h:4024 [inline]
BUG: KASAN: slab-out-of-bounds in ext4_dir_entry_len fs/ext4/ext4.h:4060 [inline]
BUG: KASAN: slab-out-of-bounds in dx_root_limit fs/ext4/namei.c:583 [inline]
BUG: KASAN: slab-out-of-bounds in dx_probe+0x1ac9/0x1d90 fs/ext4/namei.c:861
Read of size 4 at addr ffff88816a408c10 by task syz.2.19/5980

CPU: 1 UID: 0 PID: 5980 Comm: syz.2.19 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xba/0x230 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 ext4_dir_entry_is_tail fs/ext4/ext4.h:4001 [inline]
 ext4_dirent_get_data_len fs/ext4/ext4.h:4024 [inline]
 ext4_dir_entry_len fs/ext4/ext4.h:4060 [inline]
 dx_root_limit fs/ext4/namei.c:583 [inline]
 dx_probe+0x1ac9/0x1d90 fs/ext4/namei.c:861
 ext4_dx_find_entry fs/ext4/namei.c:1812 [inline]
 __ext4_find_entry+0x5a9/0x2140 fs/ext4/namei.c:1652
 ext4_lookup_entry fs/ext4/namei.c:1794 [inline]
 ext4_lookup+0x17b/0x710 fs/ext4/namei.c:1860
 __lookup_slow+0x2b7/0x410 fs/namei.c:1916
 lookup_slow+0x53/0x70 fs/namei.c:1933
 walk_component fs/namei.c:2279 [inline]
 lookup_last fs/namei.c:2780 [inline]
 path_lookupat+0x3f5/0x8c0 fs/namei.c:2804
 filename_lookup+0x256/0x5d0 fs/namei.c:2833
 user_path_at+0x40/0x160 fs/namei.c:3612
 do_mount fs/namespace.c:4169 [inline]
 __do_sys_mount fs/namespace.c:4361 [inline]
 __se_sys_mount+0x2dc/0x420 fs/namespace.c:4338
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f518919c819
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f5189fbb028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f5189415fa0 RCX: 00007f518919c819
RDX: 0000200000000140 RSI: 0000200000000100 RDI: 0000000000000000
RBP: 00007f5189232c91 R08: 0000200000000d80 R09: 0000000000000000
R10: 0000000001302060 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5189416038 R14: 00007f5189415fa0 R15: 00007ffc5d8d15b8
 </TASK>

Allocated by task 5243:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __do_kmalloc_node mm/slub.c:5260 [inline]
 __kvmalloc_node_noprof+0x528/0x8a0 mm/slub.c:6752
 evdev_open+0xeb/0x5b0 drivers/input/evdev.c:468
 chrdev_open+0x4cd/0x5e0 fs/char_dev.c:411
 do_dentry_open+0x785/0x14e0 fs/open.c:949
 vfs_open+0x3b/0x340 fs/open.c:1081
 do_open fs/namei.c:4671 [inline]
 path_openat+0x2e08/0x3860 fs/namei.c:4830
 do_file_open+0x23e/0x4a0 fs/namei.c:4859
 do_sys_openat2+0x113/0x200 fs/open.c:1366
 do_sys_open fs/open.c:1372 [inline]
 __do_sys_openat fs/open.c:1388 [inline]
 __se_sys_openat fs/open.c:1383 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1383
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88816a408000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 1088 bytes to the right of
 allocated 2000-byte region [ffff88816a408000, ffff88816a4087d0)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x16a408
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x57ff00000000040(head|node=1|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 057ff00000000040 ffff888100042000 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800080008 00000000f5000000 0000000000000000
head: 057ff00000000040 ffff888100042000 dead000000000100 dead000000000122
head: 0000000000000000 0000000800080008 00000000f5000000 0000000000000000
head: 057ff00000000003 ffffea0005a90201 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5243, tgid 5243 (acpid), ts 25906150911, free_ts 21905842969
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x231/0x280 mm/page_alloc.c:1889
 prep_new_page mm/page_alloc.c:1897 [inline]
 get_page_from_freelist+0x24dc/0x2580 mm/page_alloc.c:3962
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5250
 alloc_slab_page mm/slub.c:3292 [inline]
 allocate_slab+0x77/0x660 mm/slub.c:3481
 new_slab mm/slub.c:3539 [inline]
 refill_objects+0x331/0x3c0 mm/slub.c:7175
 refill_sheaf mm/slub.c:2812 [inline]
 __pcs_replace_empty_main+0x2e6/0x730 mm/slub.c:4615
 alloc_from_pcs mm/slub.c:4717 [inline]
 slab_alloc_node mm/slub.c:4851 [inline]
 __do_kmalloc_node mm/slub.c:5259 [inline]
 __kvmalloc_node_noprof+0x657/0x8a0 mm/slub.c:6752
 evdev_open+0xeb/0x5b0 drivers/input/evdev.c:468
 chrdev_open+0x4cd/0x5e0 fs/char_dev.c:411
 do_dentry_open+0x785/0x14e0 fs/open.c:949
 vfs_open+0x3b/0x340 fs/open.c:1081
 do_open fs/namei.c:4671 [inline]
 path_openat+0x2e08/0x3860 fs/namei.c:4830
 do_file_open+0x23e/0x4a0 fs/namei.c:4859
 do_sys_openat2+0x113/0x200 fs/open.c:1366
 do_sys_open fs/open.c:1372 [inline]
 __do_sys_openat fs/open.c:1388 [inline]
 __se_sys_openat fs/open.c:1383 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1383
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
page last free pid 9 tgid 9 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1433 [inline]
 __free_frozen_pages+0xc2b/0xdb0 mm/page_alloc.c:2978
 vfree+0x25a/0x400 mm/vmalloc.c:3479
 delayed_vfree_work+0x55/0x80 mm/vmalloc.c:3398
 process_one_work kernel/workqueue.c:3276 [inline]
 process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Memory state around the buggy address:
 ffff88816a408b00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88816a408b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88816a408c00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                         ^
 ffff88816a408c80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88816a408d00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


***

KASAN: slab-use-after-free Read in __ext4_check_dir_entry

tree:      torvalds
URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux
base:      70b672833f4025341c11b22c7f83778a5cd611bc
arch:      amd64
compiler:  Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
config:    https://ci.syzbot.org/builds/7b860156-1ca9-441f-b899-ebfb5a09620d/config
syz repro: https://ci.syzbot.org/findings/e493ff66-4032-4979-9b5d-5118b2768ca5/syz_repro

EXT4-fs (loop0): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: none.
==================================================================
BUG: KASAN: slab-use-after-free in ext4_dirent_get_data_len fs/ext4/ext4.h:4040 [inline]
BUG: KASAN: slab-use-after-free in ext4_dir_entry_len fs/ext4/ext4.h:4060 [inline]
BUG: KASAN: slab-use-after-free in __ext4_check_dir_entry+0x527/0xa70 fs/ext4/dir.c:96
Read of size 1 at addr ffff88810138889c by task syz.0.24/5978

CPU: 0 UID: 0 PID: 5978 Comm: syz.0.24 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xba/0x230 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 ext4_dirent_get_data_len fs/ext4/ext4.h:4040 [inline]
 ext4_dir_entry_len fs/ext4/ext4.h:4060 [inline]
 __ext4_check_dir_entry+0x527/0xa70 fs/ext4/dir.c:96
 ext4_inlinedir_to_tree+0x6be/0xbf0 fs/ext4/inline.c:1322
 ext4_htree_fill_tree+0x50b/0x1230 fs/ext4/namei.c:1184
 ext4_dx_readdir fs/ext4/dir.c:600 [inline]
 ext4_readdir+0x2f7b/0x3870 fs/ext4/dir.c:146
 iterate_dir+0x399/0x570 fs/readdir.c:108
 __do_sys_getdents64 fs/readdir.c:412 [inline]
 __se_sys_getdents64+0xf1/0x280 fs/readdir.c:397
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff3fe19c819
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ff3fefac028 EFLAGS: 00000246 ORIG_RAX: 00000000000000d9
RAX: ffffffffffffffda RBX: 00007ff3fe415fa0 RCX: 00007ff3fe19c819
RDX: 000000000000ff80 RSI: 9999999999999999 RDI: 0000000000000004
RBP: 00007ff3fe232c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff3fe416038 R14: 00007ff3fe415fa0 R15: 00007ffd39a74998
 </TASK>

Allocated by task 5766:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __do_kmalloc_node mm/slub.c:5260 [inline]
 __kmalloc_noprof+0x35c/0x760 mm/slub.c:5272
 kmalloc_noprof include/linux/slab.h:954 [inline]
 kzalloc_noprof include/linux/slab.h:1188 [inline]
 tomoyo_encode2 security/tomoyo/realpath.c:45 [inline]
 tomoyo_encode+0x28b/0x550 security/tomoyo/realpath.c:80
 tomoyo_realpath_from_path+0x58d/0x5d0 security/tomoyo/realpath.c:283
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_check_open_permission+0x229/0x470 security/tomoyo/file.c:776
 security_file_open+0xa9/0x240 security/security.c:2637
 do_dentry_open+0x384/0x14e0 fs/open.c:926
 vfs_open+0x3b/0x340 fs/open.c:1081
 do_open fs/namei.c:4671 [inline]
 path_openat+0x2e08/0x3860 fs/namei.c:4830
 do_file_open+0x23e/0x4a0 fs/namei.c:4859
 do_sys_openat2+0x113/0x200 fs/open.c:1366
 do_sys_open fs/open.c:1372 [inline]
 __do_sys_openat fs/open.c:1388 [inline]
 __se_sys_openat fs/open.c:1383 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1383
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 5766:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2685 [inline]
 slab_free mm/slub.c:6165 [inline]
 kfree+0x1c1/0x630 mm/slub.c:6483
 tomoyo_check_open_permission+0x32c/0x470 security/tomoyo/file.c:791
 security_file_open+0xa9/0x240 security/security.c:2637
 do_dentry_open+0x384/0x14e0 fs/open.c:926
 vfs_open+0x3b/0x340 fs/open.c:1081
 do_open fs/namei.c:4671 [inline]
 path_openat+0x2e08/0x3860 fs/namei.c:4830
 do_file_open+0x23e/0x4a0 fs/namei.c:4859
 do_sys_openat2+0x113/0x200 fs/open.c:1366
 do_sys_open fs/open.c:1372 [inline]
 __do_sys_openat fs/open.c:1388 [inline]
 __se_sys_openat fs/open.c:1383 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1383
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888101388880
 which belongs to the cache kmalloc-64 of size 64
The buggy address is located 28 bytes inside of
 freed 64-byte region [ffff888101388880, ffff8881013888c0)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x101388
flags: 0x17ff00000000000(node=0|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 017ff00000000000 ffff8881000418c0 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800200020 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 26, tgid 26 (kworker/u9:0), ts 4100832473, free_ts 4100767003
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x231/0x280 mm/page_alloc.c:1889
 prep_new_page mm/page_alloc.c:1897 [inline]
 get_page_from_freelist+0x24dc/0x2580 mm/page_alloc.c:3962
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5250
 alloc_slab_page mm/slub.c:3292 [inline]
 allocate_slab+0x77/0x660 mm/slub.c:3481
 new_slab mm/slub.c:3539 [inline]
 refill_objects+0x331/0x3c0 mm/slub.c:7175
 refill_sheaf mm/slub.c:2812 [inline]
 alloc_full_sheaf mm/slub.c:2834 [inline]
 __pcs_replace_empty_main+0x40a/0x730 mm/slub.c:4626
 alloc_from_pcs mm/slub.c:4717 [inline]
 slab_alloc_node mm/slub.c:4851 [inline]
 __do_kmalloc_node mm/slub.c:5259 [inline]
 __kmalloc_noprof+0x474/0x760 mm/slub.c:5272
 kmalloc_noprof include/linux/slab.h:954 [inline]
 kzalloc_noprof include/linux/slab.h:1188 [inline]
 lsm_blob_alloc security/security.c:193 [inline]
 lsm_task_alloc security/security.c:245 [inline]
 security_task_alloc+0x4d/0x330 security/security.c:2683
 copy_process+0x16df/0x3cd0 kernel/fork.c:2206
 kernel_clone+0x248/0x8e0 kernel/fork.c:2658
 user_mode_thread+0x110/0x180 kernel/fork.c:2734
 call_usermodehelper_exec_work+0x5c/0x230 kernel/umh.c:171
 process_one_work kernel/workqueue.c:3276 [inline]
 process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
page last free pid 26 tgid 26 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1433 [inline]
 __free_frozen_pages+0xc2b/0xdb0 mm/page_alloc.c:2978
 __kasan_populate_vmalloc_do mm/kasan/shadow.c:393 [inline]
 __kasan_populate_vmalloc+0x1b2/0x1d0 mm/kasan/shadow.c:424
 kasan_populate_vmalloc include/linux/kasan.h:580 [inline]
 alloc_vmap_area+0xd73/0x14b0 mm/vmalloc.c:2129
 __get_vm_area_node+0x1f8/0x300 mm/vmalloc.c:3232
 __vmalloc_node_range_noprof+0x372/0x1730 mm/vmalloc.c:4024
 __vmalloc_node_noprof+0xc2/0x100 mm/vmalloc.c:4124
 alloc_thread_stack_node kernel/fork.c:355 [inline]
 dup_task_struct+0x292/0x9e0 kernel/fork.c:924
 copy_process+0x508/0x3cd0 kernel/fork.c:2051
 kernel_clone+0x248/0x8e0 kernel/fork.c:2658
 user_mode_thread+0x110/0x180 kernel/fork.c:2734
 call_usermodehelper_exec_work+0x5c/0x230 kernel/umh.c:171
 process_one_work kernel/workqueue.c:3276 [inline]
 process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Memory state around the buggy address:
 ffff888101388780: 00 00 00 00 00 00 00 04 fc fc fc fc fc fc fc fc
 ffff888101388800: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
>ffff888101388880: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
                            ^
 ffff888101388900: 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc
 ffff888101388980: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
==================================================================


***

KASAN: slab-use-after-free Read in dx_probe

tree:      torvalds
URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux
base:      70b672833f4025341c11b22c7f83778a5cd611bc
arch:      amd64
compiler:  Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
config:    https://ci.syzbot.org/builds/7b860156-1ca9-441f-b899-ebfb5a09620d/config
syz repro: https://ci.syzbot.org/findings/5524eff5-62fb-4cff-8d4e-7e3750aa921b/syz_repro

EXT4-fs (loop2): mounted filesystem 00000000-0000-0000-0000-000000000000 ro without journal. Quota mode: none.
==================================================================
BUG: KASAN: slab-use-after-free in ext4_dir_entry_is_tail fs/ext4/ext4.h:4001 [inline]
BUG: KASAN: slab-use-after-free in ext4_dirent_get_data_len fs/ext4/ext4.h:4024 [inline]
BUG: KASAN: slab-use-after-free in ext4_dir_entry_len fs/ext4/ext4.h:4060 [inline]
BUG: KASAN: slab-use-after-free in dx_root_limit fs/ext4/namei.c:583 [inline]
BUG: KASAN: slab-use-after-free in dx_probe+0x1ac9/0x1d90 fs/ext4/namei.c:861
Read of size 4 at addr ffff888109c42c10 by task syz.2.20/5984

CPU: 0 UID: 0 PID: 5984 Comm: syz.2.20 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xba/0x230 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 ext4_dir_entry_is_tail fs/ext4/ext4.h:4001 [inline]
 ext4_dirent_get_data_len fs/ext4/ext4.h:4024 [inline]
 ext4_dir_entry_len fs/ext4/ext4.h:4060 [inline]
 dx_root_limit fs/ext4/namei.c:583 [inline]
 dx_probe+0x1ac9/0x1d90 fs/ext4/namei.c:861
 ext4_dx_find_entry fs/ext4/namei.c:1812 [inline]
 __ext4_find_entry+0x5a9/0x2140 fs/ext4/namei.c:1652
 ext4_lookup_entry fs/ext4/namei.c:1794 [inline]
 ext4_lookup+0x17b/0x710 fs/ext4/namei.c:1860
 lookup_open fs/namei.c:4456 [inline]
 open_last_lookups fs/namei.c:4583 [inline]
 path_openat+0x11ac/0x3860 fs/namei.c:4827
 do_file_open+0x23e/0x4a0 fs/namei.c:4859
 do_sys_openat2+0x113/0x200 fs/open.c:1366
 do_sys_open fs/open.c:1372 [inline]
 __do_sys_openat fs/open.c:1388 [inline]
 __se_sys_openat fs/open.c:1383 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1383
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb97dd9c819
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fb97ec96028 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fb97e015fa0 RCX: 00007fb97dd9c819
RDX: 0000000000042041 RSI: 0000200000000700 RDI: ffffffffffffff9c
RBP: 00007fb97de32c91 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000001d R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb97e016038 R14: 00007fb97e015fa0 R15: 00007fffcac5f5a8
 </TASK>

Allocated by task 5828:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __do_kmalloc_node mm/slub.c:5260 [inline]
 __kmalloc_noprof+0x35c/0x760 mm/slub.c:5272
 kmalloc_noprof include/linux/slab.h:954 [inline]
 tomoyo_realpath_from_path+0xe3/0x5d0 security/tomoyo/realpath.c:251
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_path_perm+0x283/0x560 security/tomoyo/file.c:827
 tomoyo_path_symlink+0xab/0xf0 security/tomoyo/tomoyo.c:212
 security_path_symlink+0x16f/0x360 security/security.c:1477
 filename_symlinkat+0x134/0x410 fs/namei.c:5638
 __do_sys_symlink fs/namei.c:5667 [inline]
 __se_sys_symlink+0x4d/0x2b0 fs/namei.c:5663
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 5828:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2685 [inline]
 slab_free mm/slub.c:6165 [inline]
 kfree+0x1c1/0x630 mm/slub.c:6483
 tomoyo_realpath_from_path+0x598/0x5d0 security/tomoyo/realpath.c:286
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_path_perm+0x283/0x560 security/tomoyo/file.c:827
 tomoyo_path_symlink+0xab/0xf0 security/tomoyo/tomoyo.c:212
 security_path_symlink+0x16f/0x360 security/security.c:1477
 filename_symlinkat+0x134/0x410 fs/namei.c:5638
 __do_sys_symlink fs/namei.c:5667 [inline]
 __se_sys_symlink+0x4d/0x2b0 fs/namei.c:5663
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888109c42000
 which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 3088 bytes inside of
 freed 4096-byte region [ffff888109c42000, ffff888109c43000)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x109c40
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x17ff00000000040(head|node=0|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 017ff00000000040 ffff888100042140 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800040004 00000000f5000000 0000000000000000
head: 017ff00000000040 ffff888100042140 dead000000000100 dead000000000122
head: 0000000000000000 0000000800040004 00000000f5000000 0000000000000000
head: 017ff00000000003 ffffea0004271001 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd2040(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5828, tgid 5828 (udevd), ts 67573015608, free_ts 47549723112
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x231/0x280 mm/page_alloc.c:1889
 prep_new_page mm/page_alloc.c:1897 [inline]
 get_page_from_freelist+0x24dc/0x2580 mm/page_alloc.c:3962
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5250
 alloc_slab_page mm/slub.c:3292 [inline]
 allocate_slab+0x77/0x660 mm/slub.c:3481
 new_slab mm/slub.c:3539 [inline]
 refill_objects+0x331/0x3c0 mm/slub.c:7175
 refill_sheaf mm/slub.c:2812 [inline]
 __pcs_replace_empty_main+0x2e6/0x730 mm/slub.c:4615
 alloc_from_pcs mm/slub.c:4717 [inline]
 slab_alloc_node mm/slub.c:4851 [inline]
 __do_kmalloc_node mm/slub.c:5259 [inline]
 __kmalloc_noprof+0x474/0x760 mm/slub.c:5272
 kmalloc_noprof include/linux/slab.h:954 [inline]
 tomoyo_realpath_from_path+0xe3/0x5d0 security/tomoyo/realpath.c:251
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_path_perm+0x283/0x560 security/tomoyo/file.c:827
 tomoyo_path_symlink+0xab/0xf0 security/tomoyo/tomoyo.c:212
 security_path_symlink+0x16f/0x360 security/security.c:1477
 filename_symlinkat+0x134/0x410 fs/namei.c:5638
 __do_sys_symlink fs/namei.c:5667 [inline]
 __se_sys_symlink+0x4d/0x2b0 fs/namei.c:5663
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 5718 tgid 5718 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1433 [inline]
 __free_frozen_pages+0xc2b/0xdb0 mm/page_alloc.c:2978
 __slab_free+0x263/0x2b0 mm/slub.c:5573
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x97/0x100 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4538 [inline]
 slab_alloc_node mm/slub.c:4866 [inline]
 kmem_cache_alloc_noprof+0x2bc/0x650 mm/slub.c:4873
 alloc_filename fs/namei.c:142 [inline]
 do_getname+0x2e/0x250 fs/namei.c:182
 getname include/linux/fs.h:2512 [inline]
 getname_maybe_null include/linux/fs.h:2519 [inline]
 class_filename_maybe_null_constructor include/linux/fs.h:2543 [inline]
 vfs_fstatat+0x45/0x170 fs/stat.c:368
 __do_sys_newfstatat fs/stat.c:538 [inline]
 __se_sys_newfstatat fs/stat.c:532 [inline]
 __x64_sys_newfstatat+0x151/0x200 fs/stat.c:532
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff888109c42b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888109c42b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888109c42c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                         ^
 ffff888109c42c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888109c42d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


***

KASAN: use-after-free Read in __ext4_check_dir_entry

tree:      torvalds
URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux
base:      70b672833f4025341c11b22c7f83778a5cd611bc
arch:      amd64
compiler:  Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
config:    https://ci.syzbot.org/builds/7b860156-1ca9-441f-b899-ebfb5a09620d/config
syz repro: https://ci.syzbot.org/findings/21333690-a422-407b-92c7-9247a0075b74/syz_repro

loop1: lost filesystem error report for type 5 error -117
EXT4-fs (loop1): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: none.
==================================================================
BUG: KASAN: use-after-free in ext4_dirent_get_data_len fs/ext4/ext4.h:4040 [inline]
BUG: KASAN: use-after-free in ext4_dir_entry_len fs/ext4/ext4.h:4060 [inline]
BUG: KASAN: use-after-free in __ext4_check_dir_entry+0x527/0xa70 fs/ext4/dir.c:96
Read of size 1 at addr ffff88810da3609c by task syz.1.20/5966

CPU: 0 UID: 0 PID: 5966 Comm: syz.1.20 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xba/0x230 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 ext4_dirent_get_data_len fs/ext4/ext4.h:4040 [inline]
 ext4_dir_entry_len fs/ext4/ext4.h:4060 [inline]
 __ext4_check_dir_entry+0x527/0xa70 fs/ext4/dir.c:96
 ext4_inlinedir_to_tree+0x6be/0xbf0 fs/ext4/inline.c:1322
 ext4_htree_fill_tree+0x50b/0x1230 fs/ext4/namei.c:1184
 ext4_dx_readdir fs/ext4/dir.c:600 [inline]
 ext4_readdir+0x2f7b/0x3870 fs/ext4/dir.c:146
 iterate_dir+0x399/0x570 fs/readdir.c:108
 __do_sys_getdents64 fs/readdir.c:412 [inline]
 __se_sys_getdents64+0xf1/0x280 fs/readdir.c:397
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb82a19c819
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fb82b01a028 EFLAGS: 00000246 ORIG_RAX: 00000000000000d9
RAX: ffffffffffffffda RBX: 00007fb82a415fa0 RCX: 00007fb82a19c819
RDX: 000000000000ff80 RSI: 9999999999999999 RDI: 0000000000000004
RBP: 00007fb82a232c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb82a416038 R14: 00007fb82a415fa0 R15: 00007ffdc30464e8
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88810da36000 pfn:0x10da36
flags: 0x17ff00000000000(node=0|zone=2|lastcpupid=0x7ff)
page_type: f0(buddy)
raw: 017ff00000000000 ffffea0004364708 ffffea000436a7c8 0000000000000000
raw: ffff88810da36000 0000000000000000 00000000f0000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2c00(GFP_NOIO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 15037633903, free_ts 26770192426
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x231/0x280 mm/page_alloc.c:1889
 prep_new_page mm/page_alloc.c:1897 [inline]
 get_page_from_freelist+0x24dc/0x2580 mm/page_alloc.c:3962
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5250
 alloc_slab_page mm/slub.c:3292 [inline]
 allocate_slab+0x77/0x660 mm/slub.c:3481
 new_slab mm/slub.c:3539 [inline]
 refill_objects+0x331/0x3c0 mm/slub.c:7175
 refill_sheaf mm/slub.c:2812 [inline]
 __pcs_replace_empty_main+0x2e6/0x730 mm/slub.c:4615
 alloc_from_pcs mm/slub.c:4717 [inline]
 slab_alloc_node mm/slub.c:4851 [inline]
 __do_kmalloc_node mm/slub.c:5259 [inline]
 __kmalloc_noprof+0x474/0x760 mm/slub.c:5272
 kmalloc_noprof include/linux/slab.h:954 [inline]
 usb_alloc_urb+0x46/0x150 drivers/usb/core/urb.c:75
 usb_internal_control_msg drivers/usb/core/message.c:110 [inline]
 usb_control_msg+0x118/0x3e0 drivers/usb/core/message.c:167
 usb_get_descriptor+0xb1/0x3e0 drivers/usb/core/message.c:852
 usb_get_configuration+0x3b9/0x54f0 drivers/usb/core/config.c:986
 usb_enumerate_device drivers/usb/core/hub.c:2527 [inline]
 usb_new_device+0x145/0x16f0 drivers/usb/core/hub.c:2665
 register_root_hub+0x270/0x5f0 drivers/usb/core/hcd.c:990
 usb_add_hcd+0xba1/0x10b0 drivers/usb/core/hcd.c:2987
 vhci_hcd_probe+0x1fa/0x3e0 drivers/usb/usbip/vhci_hcd.c:1401
 platform_probe+0xf9/0x190 drivers/base/platform.c:1418
page last free pid 5262 tgid 5262 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1433 [inline]
 __free_frozen_pages+0xc2b/0xdb0 mm/page_alloc.c:2978
 __slab_free+0x263/0x2b0 mm/slub.c:5573
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x97/0x100 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4538 [inline]
 slab_alloc_node mm/slub.c:4866 [inline]
 kmem_cache_alloc_noprof+0x2bc/0x650 mm/slub.c:4873
 alloc_empty_file+0x55/0x1d0 fs/file_table.c:237
 path_openat+0x10f/0x3860 fs/namei.c:4816
 do_file_open+0x23e/0x4a0 fs/namei.c:4859
 do_sys_openat2+0x113/0x200 fs/open.c:1366
 do_sys_open fs/open.c:1372 [inline]
 __do_sys_openat fs/open.c:1388 [inline]
 __se_sys_openat fs/open.c:1383 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1383
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff88810da35f80: 00 00 00 00 00 00 00 04 fc fc fc fc fc fc fc fc
 ffff88810da36000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88810da36080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                            ^
 ffff88810da36100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88810da36180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================


***

If these findings have caused you to resend the series or submit a
separate fix, please add the following tag to your commit message:
  Tested-by: syzbot@syzkaller.appspotmail.com

---
This report is generated by a bot. It may contain errors.
syzbot ci engineers can be reached at syzkaller@googlegroups.com.

To test a patch for this bug, please reply with `#syz test`
(should be on a separate line).

The patch should be attached to the email.
Note: arguments like custom git repos and branches are not supported.

The email will later be sent to:
[adilger.kernel@dilger.ca adilger@dilger.ca artem.blagodarenko@gmail.com linux-ext4@vger.kernel.org pravin.shelar@sun.com]

If the report looks fine to you, reply with:
#syz upstream

If the report is a false positive, reply with
#syz invalid


^ permalink raw reply	[flat|nested] 6+ messages in thread
* [moderation/CI] Re: Data in direntry (dirdata) feature
@ 2026-06-11 10:19 syzbot ci
  2026-06-11 10:27 ` Aleksandr Nogikh
  0 siblings, 1 reply; 6+ messages in thread
From: syzbot ci @ 2026-06-11 10:19 UTC (permalink / raw)
  To: syzkaller-upstream-moderation; +Cc: syzbot

syzbot ci has tested the following series

[v2] Data in direntry (dirdata) feature
https://lore.kernel.org/all/20260610152417.13576-1-ablagodarenko@thelustrecollective.com
* [PATCH v2 01/10] ext4: replace ext4_dir_entry with ext4_dir_entry_2
* [PATCH v2 02/10] ext4: add ext4_dir_entry_is_tail()
* [PATCH v2 03/10] ext4: refactor dx_root to support variable dirent sizes
* [PATCH v2 04/10] ext4: add dirdata format definitions and access helpers
* [PATCH v2 05/10] ext4: preserve dirdata bits in get_dtype()
* [PATCH v2 06/10] ext4: add ext4_dir_entry_len() and harden dirdata parsing
* [PATCH v2 07/10] ext4: rename ext4_dir_rec_len() and clarify dirdata usage
* [PATCH v2 08/10] ext4: dirdata feature
* [PATCH v2 09/10] ext4: add dirdata set/get helpers
* [PATCH v2 10/10] ext4: Add EXT4_IOC_SET_LUFID ioctl for setting LUFID on directory entries

and found the following issues:
* KASAN: slab-out-of-bounds Read in __ext4_check_dir_entry
* KASAN: slab-out-of-bounds Read in ext4_inlinedir_to_tree
* KASAN: slab-use-after-free Read in __ext4_check_dir_entry
* KASAN: slab-use-after-free Read in ext4_inlinedir_to_tree
* KASAN: use-after-free Read in __ext4_check_dir_entry

Full report is available here:
https://ci.syzbot.org/series/5bf0e2fa-2e68-4532-8396-4568879b2788

***

KASAN: slab-out-of-bounds Read in __ext4_check_dir_entry

tree:      torvalds
URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux
base:      9716c086c8e8b141d35aa61f2e96a2e83de212a7
arch:      amd64
compiler:  Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
config:    https://ci.syzbot.org/builds/ddf6ee7c-dfa8-4383-b004-10140edc081c/config
syz repro: https://ci.syzbot.org/findings/b0854918-13f9-49dd-ab30-12154f0debe2/syz_repro

loop0: lost filesystem error report for type 5 error -117
EXT4-fs (loop0): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: none.
==================================================================
BUG: KASAN: slab-out-of-bounds in ext4_dirent_get_data_len fs/ext4/ext4.h:4069 [inline]
BUG: KASAN: slab-out-of-bounds in ext4_dir_entry_len fs/ext4/ext4.h:4096 [inline]
BUG: KASAN: slab-out-of-bounds in __ext4_check_dir_entry+0x65a/0xc40 fs/ext4/dir.c:96
Read of size 1 at addr ffff8881022db7f5 by task syz.0.23/5815

CPU: 1 UID: 0 PID: 5815 Comm: syz.0.23 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description+0x55/0x1e0 mm/kasan/report.c:378
 print_report+0x58/0x70 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 ext4_dirent_get_data_len fs/ext4/ext4.h:4069 [inline]
 ext4_dir_entry_len fs/ext4/ext4.h:4096 [inline]
 __ext4_check_dir_entry+0x65a/0xc40 fs/ext4/dir.c:96
 ext4_check_all_de+0x66/0x150 fs/ext4/dir.c:657
 ext4_convert_inline_data_nolock+0x1b7/0x990 fs/ext4/inline.c:1121
 ext4_try_add_inline_entry+0x604/0x8e0 fs/ext4/inline.c:1247
 __ext4_add_entry+0x390/0x1f40 fs/ext4/namei.c:2529
 ext4_add_entry fs/ext4/namei.c:2613 [inline]
 ext4_mkdir+0x5e5/0xce0 fs/ext4/namei.c:3175
 vfs_mkdir+0x413/0x630 fs/namei.c:5271
 filename_mkdirat+0x285/0x510 fs/namei.c:5304
 __do_sys_mkdirat fs/namei.c:5325 [inline]
 __se_sys_mkdirat+0x35/0x150 fs/namei.c:5322
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f669359bcc7
Code: 00 66 90 48 89 f2 b9 00 01 00 00 48 89 fe bf 9c ff ff ff e9 db f7 ff ff 66 2e 0f 1f 84 00 00 00 00 00 90 b8 02 01 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd42381d38 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007ffd42381dc0 RCX: 00007f669359bcc7
RDX: 00000000000001ff RSI: 0000200000001200 RDI: 00000000ffffff9c
RBP: 00002000000024c0 R08: 0000200000000240 R09: 0000000000000000
R10: 00002000000024c0 R11: 0000000000000246 R12: 0000200000001200
R13: 00007ffd42381d80 R14: 0000000000000000 R15: 0000000000000000
 </TASK>

Allocated by task 5066:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __kmalloc_cache_noprof+0x31c/0x660 mm/slub.c:5420
 kmalloc_noprof include/linux/slab.h:950 [inline]
 kzalloc_noprof include/linux/slab.h:1188 [inline]
 kernfs_get_open_node fs/kernfs/file.c:543 [inline]
 kernfs_fop_open+0x862/0xda0 fs/kernfs/file.c:718
 do_dentry_open+0x822/0x13a0 fs/open.c:947
 vfs_open+0x3b/0x340 fs/open.c:1079
 do_open fs/namei.c:4699 [inline]
 path_openat+0x2e08/0x3860 fs/namei.c:4858
 do_file_open+0x23e/0x4a0 fs/namei.c:4887
 do_sys_openat2+0x113/0x200 fs/open.c:1364
 do_sys_open fs/open.c:1370 [inline]
 __do_sys_openat fs/open.c:1386 [inline]
 __se_sys_openat fs/open.c:1381 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1381
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Last potentially related work creation:
 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57
 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556
 kvfree_call_rcu+0x100/0x430 mm/slab_common.c:1970
 kernfs_unlink_open_file+0x3fe/0x4b0 fs/kernfs/file.c:604
 kernfs_fop_release+0x2eb/0x440 fs/kernfs/file.c:783
 __fput+0x44f/0xa60 fs/file_table.c:510
 fput_close_sync+0x11f/0x240 fs/file_table.c:615
 __do_sys_close fs/open.c:1507 [inline]
 __se_sys_close fs/open.c:1492 [inline]
 __x64_sys_close+0x7e/0x110 fs/open.c:1492
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff8881022db700
 which belongs to the cache kmalloc-128 of size 128
The buggy address is located 117 bytes to the right of
 allocated 128-byte region [ffff8881022db700, ffff8881022db780)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1022db
flags: 0x17ff00000000000(node=0|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 017ff00000000000 ffff888100041a00 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800100010 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2000(__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 0, tgid 0 (swapper/0), ts 2408938923, free_ts 0
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x22d/0x280 mm/page_alloc.c:1853
 prep_new_page mm/page_alloc.c:1861 [inline]
 get_page_from_freelist+0x2593/0x2610 mm/page_alloc.c:3941
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5221
 alloc_slab_page mm/slub.c:3278 [inline]
 allocate_slab+0x77/0x660 mm/slub.c:3467
 new_slab mm/slub.c:3525 [inline]
 refill_objects+0x339/0x3d0 mm/slub.c:7272
 refill_sheaf mm/slub.c:2816 [inline]
 __pcs_replace_empty_main+0x321/0x720 mm/slub.c:4652
 alloc_from_pcs mm/slub.c:4750 [inline]
 slab_alloc_node mm/slub.c:4884 [inline]
 __do_kmalloc_node mm/slub.c:5295 [inline]
 __kmalloc_noprof+0x474/0x760 mm/slub.c:5308
 kmalloc_noprof include/linux/slab.h:954 [inline]
 kzalloc_noprof include/linux/slab.h:1188 [inline]
 __alloc_empty_sheaf mm/slub.c:2768 [inline]
 alloc_empty_sheaf mm/slub.c:2783 [inline]
 __pcs_replace_empty_main+0x2df/0x720 mm/slub.c:4647
 alloc_from_pcs mm/slub.c:4750 [inline]
 slab_alloc_node mm/slub.c:4884 [inline]
 kmem_cache_alloc_noprof+0x37d/0x650 mm/slub.c:4906
 dup_fd+0x55/0xb40 fs/file.c:390
 copy_files+0xc8/0x120 kernel/fork.c:1639
 copy_process+0x1d94/0x4440 kernel/fork.c:2252
 kernel_clone+0x2d7/0x940 kernel/fork.c:2722
 user_mode_thread+0x110/0x180 kernel/fork.c:2798
 rest_init+0x23/0x300 init/main.c:727
 start_kernel+0x38a/0x3e0 init/main.c:1220
page_owner free stack trace missing

Memory state around the buggy address:
 ffff8881022db680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8881022db700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8881022db780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                                                             ^
 ffff8881022db800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8881022db880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


***

KASAN: slab-out-of-bounds Read in ext4_inlinedir_to_tree

tree:      torvalds
URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux
base:      9716c086c8e8b141d35aa61f2e96a2e83de212a7
arch:      amd64
compiler:  Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
config:    https://ci.syzbot.org/builds/ddf6ee7c-dfa8-4383-b004-10140edc081c/config
syz repro: https://ci.syzbot.org/findings/2dff870b-f382-4c93-8d8d-b2291d921224/syz_repro

loop1: lost filesystem error report for type 5 error -117
EXT4-fs (loop1): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: none.
==================================================================
BUG: KASAN: slab-out-of-bounds in ext4_dir_entry_len fs/ext4/ext4.h:4095 [inline]
BUG: KASAN: slab-out-of-bounds in ext4_inlinedir_to_tree+0xda5/0x10d0 fs/ext4/inline.c:1335
Read of size 2 at addr ffff888115a3183c by task syz.1.18/5839

CPU: 1 UID: 0 PID: 5839 Comm: syz.1.18 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description+0x55/0x1e0 mm/kasan/report.c:378
 print_report+0x58/0x70 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 ext4_dir_entry_len fs/ext4/ext4.h:4095 [inline]
 ext4_inlinedir_to_tree+0xda5/0x10d0 fs/ext4/inline.c:1335
 ext4_htree_fill_tree+0x517/0x1230 fs/ext4/namei.c:1182
 ext4_dx_readdir fs/ext4/dir.c:600 [inline]
 ext4_readdir+0x2db4/0x3640 fs/ext4/dir.c:146
 iterate_dir+0x399/0x570 fs/readdir.c:110
 __do_sys_getdents64 fs/readdir.c:399 [inline]
 __se_sys_getdents64+0xf1/0x280 fs/readdir.c:384
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3e02b9ce59
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f3e03ad5028 EFLAGS: 00000246 ORIG_RAX: 00000000000000d9
RAX: ffffffffffffffda RBX: 00007f3e02e15fa0 RCX: 00007f3e02b9ce59
RDX: 0000000000001000 RSI: 0000200000000f80 RDI: 0000000000000004
RBP: 00007f3e02c32d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3e02e16038 R14: 00007f3e02e15fa0 R15: 00007ffcaa902298
 </TASK>

Allocated by task 5839:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __do_kmalloc_node mm/slub.c:5296 [inline]
 __kmalloc_noprof+0x35c/0x760 mm/slub.c:5308
 kmalloc_noprof include/linux/slab.h:954 [inline]
 ext4_inlinedir_to_tree+0x312/0x10d0 fs/ext4/inline.c:1292
 ext4_htree_fill_tree+0x517/0x1230 fs/ext4/namei.c:1182
 ext4_dx_readdir fs/ext4/dir.c:600 [inline]
 ext4_readdir+0x2db4/0x3640 fs/ext4/dir.c:146
 iterate_dir+0x399/0x570 fs/readdir.c:110
 __do_sys_getdents64 fs/readdir.c:399 [inline]
 __se_sys_getdents64+0xf1/0x280 fs/readdir.c:384
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888115a31800
 which belongs to the cache kmalloc-64 of size 64
The buggy address is located 0 bytes to the right of
 allocated 60-byte region [ffff888115a31800, ffff888115a3183c)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x115a31
flags: 0x17ff00000000000(node=0|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 017ff00000000000 ffff8881000418c0 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800200020 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2c40(GFP_NOFS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5051, tgid 5051 (acpid), ts 27203740677, free_ts 27201732767
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x22d/0x280 mm/page_alloc.c:1853
 prep_new_page mm/page_alloc.c:1861 [inline]
 get_page_from_freelist+0x2593/0x2610 mm/page_alloc.c:3941
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5221
 alloc_slab_page mm/slub.c:3278 [inline]
 allocate_slab+0x77/0x660 mm/slub.c:3467
 new_slab mm/slub.c:3525 [inline]
 refill_objects+0x339/0x3d0 mm/slub.c:7272
 refill_sheaf mm/slub.c:2816 [inline]
 __pcs_replace_empty_main+0x321/0x720 mm/slub.c:4652
 alloc_from_pcs mm/slub.c:4750 [inline]
 slab_alloc_node mm/slub.c:4884 [inline]
 __do_kmalloc_node mm/slub.c:5295 [inline]
 __kmalloc_noprof+0x474/0x760 mm/slub.c:5308
 kmalloc_noprof include/linux/slab.h:954 [inline]
 kzalloc_noprof include/linux/slab.h:1188 [inline]
 tomoyo_get_name+0x20c/0x590 security/tomoyo/memory.c:173
 tomoyo_parse_name_union+0xd9/0x130 security/tomoyo/util.c:260
 tomoyo_update_path_acl security/tomoyo/file.c:399 [inline]
 tomoyo_write_file+0x3a6/0xc50 security/tomoyo/file.c:1027
 tomoyo_write_domain2 security/tomoyo/common.c:1160 [inline]
 tomoyo_add_entry security/tomoyo/common.c:2177 [inline]
 tomoyo_supervisor+0x1208/0x1570 security/tomoyo/common.c:2238
 tomoyo_audit_path_log security/tomoyo/file.c:169 [inline]
 tomoyo_path_permission+0x25a/0x380 security/tomoyo/file.c:592
 tomoyo_check_open_permission+0x2b2/0x470 security/tomoyo/file.c:782
 security_file_open+0xa9/0x240 security/security.c:2739
 do_dentry_open+0x4a8/0x13a0 fs/open.c:924
 vfs_open+0x3b/0x340 fs/open.c:1079
page last free pid 15 tgid 15 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1397 [inline]
 __free_frozen_pages+0xc1c/0xd30 mm/page_alloc.c:2938
 __tlb_remove_table_free mm/mmu_gather.c:228 [inline]
 tlb_remove_table_rcu+0x85/0x100 mm/mmu_gather.c:291
 rcu_do_batch kernel/rcu/tree.c:2617 [inline]
 rcu_core+0x7cd/0x1070 kernel/rcu/tree.c:2869
 handle_softirqs+0x22a/0x840 kernel/softirq.c:622
 run_ksoftirqd+0x36/0x60 kernel/softirq.c:1076
 smpboot_thread_fn+0x541/0xa50 kernel/smpboot.c:160
 kthread+0x389/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Memory state around the buggy address:
 ffff888115a31700: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff888115a31780: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc
>ffff888115a31800: 00 00 00 00 00 00 00 04 fc fc fc fc fc fc fc fc
                                        ^
 ffff888115a31880: 00 00 00 00 00 00 02 fc fc fc fc fc fc fc fc fc
 ffff888115a31900: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
==================================================================


***

KASAN: slab-use-after-free Read in __ext4_check_dir_entry

tree:      torvalds
URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux
base:      9716c086c8e8b141d35aa61f2e96a2e83de212a7
arch:      amd64
compiler:  Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
config:    https://ci.syzbot.org/builds/ddf6ee7c-dfa8-4383-b004-10140edc081c/config
syz repro: https://ci.syzbot.org/findings/f1d48ea1-6e87-4d64-9c13-8bf8aed109fc/syz_repro

loop0: lost filesystem error report for type 5 error -117
EXT4-fs (loop0): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: none.
==================================================================
BUG: KASAN: slab-use-after-free in ext4_dirent_get_data_len fs/ext4/ext4.h:4069 [inline]
BUG: KASAN: slab-use-after-free in ext4_dir_entry_len fs/ext4/ext4.h:4096 [inline]
BUG: KASAN: slab-use-after-free in __ext4_check_dir_entry+0x65a/0xc40 fs/ext4/dir.c:96
Read of size 1 at addr ffff888114d8c045 by task syz.0.20/5821

CPU: 1 UID: 0 PID: 5821 Comm: syz.0.20 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description+0x55/0x1e0 mm/kasan/report.c:378
 print_report+0x58/0x70 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 ext4_dirent_get_data_len fs/ext4/ext4.h:4069 [inline]
 ext4_dir_entry_len fs/ext4/ext4.h:4096 [inline]
 __ext4_check_dir_entry+0x65a/0xc40 fs/ext4/dir.c:96
 ext4_find_dest_de+0x136/0x770 fs/ext4/namei.c:2203
 ext4_add_dirent_to_inline+0xcf/0x430 fs/ext4/inline.c:984
 ext4_try_add_inline_entry+0x235/0x8e0 fs/ext4/inline.c:1213
 __ext4_add_entry+0x390/0x1f40 fs/ext4/namei.c:2529
 ext4_add_entry fs/ext4/namei.c:2613 [inline]
 ext4_add_nondir+0x111/0x310 fs/ext4/namei.c:2936
 ext4_create+0x2e9/0x470 fs/ext4/namei.c:2982
 lookup_open fs/namei.c:4511 [inline]
 open_last_lookups fs/namei.c:4611 [inline]
 path_openat+0x1395/0x3860 fs/namei.c:4855
 do_file_open+0x23e/0x4a0 fs/namei.c:4887
 do_sys_openat2+0x113/0x200 fs/open.c:1364
 do_sys_open fs/open.c:1370 [inline]
 __do_sys_openat fs/open.c:1386 [inline]
 __se_sys_openat fs/open.c:1381 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1381
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f922219ce59
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f9223137028 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f9222415fa0 RCX: 00007f922219ce59
RDX: 0000000000042042 RSI: 0000200000000080 RDI: 0000000000000004
RBP: 00007f9222232d6f R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000014a R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9222416038 R14: 00007f9222415fa0 R15: 00007ffd01a2d448
 </TASK>

Allocated by task 5484:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 unpoison_slab_object mm/kasan/common.c:340 [inline]
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4570 [inline]
 slab_alloc_node mm/slub.c:4899 [inline]
 kmem_cache_alloc_node_noprof+0x384/0x690 mm/slub.c:4951
 kmalloc_reserve net/core/skbuff.c:613 [inline]
 __alloc_skb+0x27d/0x7d0 net/core/skbuff.c:713
 alloc_skb include/linux/skbuff.h:1385 [inline]
 nlmsg_new include/net/netlink.h:1055 [inline]
 mpls_netconf_notify_devconf+0x46/0x100 net/mpls/af_mpls.c:1217
 mpls_dev_notify+0xb2d/0xd10 net/mpls/af_mpls.c:1691
 notifier_call_chain+0x1ad/0x3d0 kernel/notifier.c:85
 call_netdevice_notifiers_extack net/core/dev.c:2287 [inline]
 call_netdevice_notifiers net/core/dev.c:2301 [inline]
 unregister_netdevice_many_notify+0x17a5/0x22c0 net/core/dev.c:12421
 ops_exit_rtnl_list net/core/net_namespace.c:187 [inline]
 ops_undo_list+0x3d3/0x940 net/core/net_namespace.c:248
 cleanup_net+0x56b/0x800 net/core/net_namespace.c:702
 process_one_work kernel/workqueue.c:3314 [inline]
 process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3397
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3478
 kthread+0x389/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Freed by task 5484:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2689 [inline]
 slab_free mm/slub.c:6251 [inline]
 kfree+0x1c5/0x640 mm/slub.c:6566
 skb_kfree_head net/core/skbuff.c:1075 [inline]
 skb_free_head net/core/skbuff.c:1087 [inline]
 skb_release_data+0x828/0xa60 net/core/skbuff.c:1114
 skb_release_all net/core/skbuff.c:1189 [inline]
 __kfree_skb+0x5d/0x210 net/core/skbuff.c:1203
 netlink_broadcast_filtered+0xe18/0xf20 net/netlink/af_netlink.c:1540
 nlmsg_multicast_filtered include/net/netlink.h:1165 [inline]
 nlmsg_multicast include/net/netlink.h:1184 [inline]
 nlmsg_notify+0xf0/0x1a0 net/netlink/af_netlink.c:2598
 mpls_dev_notify+0xb2d/0xd10 net/mpls/af_mpls.c:1691
 notifier_call_chain+0x1ad/0x3d0 kernel/notifier.c:85
 call_netdevice_notifiers_extack net/core/dev.c:2287 [inline]
 call_netdevice_notifiers net/core/dev.c:2301 [inline]
 unregister_netdevice_many_notify+0x17a5/0x22c0 net/core/dev.c:12421
 ops_exit_rtnl_list net/core/net_namespace.c:187 [inline]
 ops_undo_list+0x3d3/0x940 net/core/net_namespace.c:248
 cleanup_net+0x56b/0x800 net/core/net_namespace.c:702
 process_one_work kernel/workqueue.c:3314 [inline]
 process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3397
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3478
 kthread+0x389/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

The buggy address belongs to the object at ffff888114d8c000
 which belongs to the cache skbuff_small_head of size 704
The buggy address is located 69 bytes inside of
 freed 704-byte region [ffff888114d8c000, ffff888114d8c2c0)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x114d8c
head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x17ff00000000040(head|node=0|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 017ff00000000040 ffff888160416b40 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800120012 00000000f5000000 0000000000000000
head: 017ff00000000040 ffff888160416b40 dead000000000100 dead000000000122
head: 0000000000000000 0000000800120012 00000000f5000000 0000000000000000
head: 017ff00000000002 ffffffffffffff01 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000004
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5484, tgid 5484 (kworker/u8:2), ts 72573003529, free_ts 72546506446
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x22d/0x280 mm/page_alloc.c:1853
 prep_new_page mm/page_alloc.c:1861 [inline]
 get_page_from_freelist+0x2593/0x2610 mm/page_alloc.c:3941
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5221
 alloc_slab_page mm/slub.c:3278 [inline]
 allocate_slab+0x77/0x660 mm/slub.c:3467
 new_slab mm/slub.c:3525 [inline]
 refill_objects+0x339/0x3d0 mm/slub.c:7272
 refill_sheaf mm/slub.c:2816 [inline]
 __pcs_replace_empty_main+0x321/0x720 mm/slub.c:4652
 alloc_from_pcs mm/slub.c:4750 [inline]
 slab_alloc_node mm/slub.c:4884 [inline]
 kmem_cache_alloc_node_noprof+0x441/0x690 mm/slub.c:4951
 kmalloc_reserve net/core/skbuff.c:613 [inline]
 __alloc_skb+0x27d/0x7d0 net/core/skbuff.c:713
 alloc_skb include/linux/skbuff.h:1385 [inline]
 nlmsg_new include/net/netlink.h:1055 [inline]
 mpls_netconf_notify_devconf+0x46/0x100 net/mpls/af_mpls.c:1217
 mpls_dev_notify+0xb2d/0xd10 net/mpls/af_mpls.c:1691
 notifier_call_chain+0x1ad/0x3d0 kernel/notifier.c:85
 call_netdevice_notifiers_extack net/core/dev.c:2287 [inline]
 call_netdevice_notifiers net/core/dev.c:2301 [inline]
 unregister_netdevice_many_notify+0x17a5/0x22c0 net/core/dev.c:12421
 ops_exit_rtnl_list net/core/net_namespace.c:187 [inline]
 ops_undo_list+0x3d3/0x940 net/core/net_namespace.c:248
 cleanup_net+0x56b/0x800 net/core/net_namespace.c:702
 process_one_work kernel/workqueue.c:3314 [inline]
 process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3397
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3478
page last free pid 5484 tgid 5484 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1397 [inline]
 __free_frozen_pages+0xc1c/0xd30 mm/page_alloc.c:2938
 stack_depot_save_flags+0x40e/0x810 lib/stackdepot.c:735
 kasan_save_stack mm/kasan/common.c:58 [inline]
 kasan_save_track+0x4f/0x80 mm/kasan/common.c:78
 unpoison_slab_object mm/kasan/common.c:340 [inline]
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4570 [inline]
 slab_alloc_node mm/slub.c:4899 [inline]
 kmem_cache_alloc_noprof+0x2bc/0x650 mm/slub.c:4906
 kmem_alloc_batch lib/debugobjects.c:371 [inline]
 fill_pool+0x156/0x580 lib/debugobjects.c:420
 debug_objects_fill_pool lib/debugobjects.c:752 [inline]
 debug_object_activate+0x4a3/0x580 lib/debugobjects.c:841
 debug_rcu_head_queue kernel/rcu/rcu.h:236 [inline]
 __call_rcu_common kernel/rcu/tree.c:3116 [inline]
 call_rcu+0x43/0x890 kernel/rcu/tree.c:3251
 kernfs_put+0x259/0x520 fs/kernfs/dir.c:618
 kernfs_remove_by_name_ns+0xc8/0x140 fs/kernfs/dir.c:1799
 device_remove_class_symlinks+0x178/0x190 drivers/base/core.c:3479
 device_del+0x400/0x8f0 drivers/base/core.c:3881
 unregister_netdevice_many_notify+0x1d5f/0x22c0 net/core/dev.c:12456
 ops_exit_rtnl_list net/core/net_namespace.c:187 [inline]
 ops_undo_list+0x3d3/0x940 net/core/net_namespace.c:248
 cleanup_net+0x56b/0x800 net/core/net_namespace.c:702
 process_one_work kernel/workqueue.c:3314 [inline]
 process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3397

Memory state around the buggy address:
 ffff888114d8bf00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888114d8bf80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888114d8c000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                           ^
 ffff888114d8c080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888114d8c100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


***

KASAN: slab-use-after-free Read in ext4_inlinedir_to_tree

tree:      torvalds
URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux
base:      9716c086c8e8b141d35aa61f2e96a2e83de212a7
arch:      amd64
compiler:  Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
config:    https://ci.syzbot.org/builds/ddf6ee7c-dfa8-4383-b004-10140edc081c/config
syz repro: https://ci.syzbot.org/findings/f42da242-e16e-4f10-bf25-0bd7e192d989/syz_repro

loop0: lost filesystem error report for type 5 error -117
EXT4-fs (loop0): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: none.
==================================================================
BUG: KASAN: slab-use-after-free in ext4_dirent_get_data_len fs/ext4/ext4.h:4069 [inline]
BUG: KASAN: slab-use-after-free in ext4_dir_entry_len fs/ext4/ext4.h:4096 [inline]
BUG: KASAN: slab-use-after-free in ext4_inlinedir_to_tree+0x94c/0x10d0 fs/ext4/inline.c:1335
Read of size 1 at addr ffff88816fee8825 by task syz.0.20/5867

CPU: 1 UID: 0 PID: 5867 Comm: syz.0.20 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description+0x55/0x1e0 mm/kasan/report.c:378
 print_report+0x58/0x70 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 ext4_dirent_get_data_len fs/ext4/ext4.h:4069 [inline]
 ext4_dir_entry_len fs/ext4/ext4.h:4096 [inline]
 ext4_inlinedir_to_tree+0x94c/0x10d0 fs/ext4/inline.c:1335
 ext4_htree_fill_tree+0x517/0x1230 fs/ext4/namei.c:1182
 ext4_dx_readdir fs/ext4/dir.c:600 [inline]
 ext4_readdir+0x2db4/0x3640 fs/ext4/dir.c:146
 iterate_dir+0x399/0x570 fs/readdir.c:110
 __do_sys_getdents fs/readdir.c:319 [inline]
 __se_sys_getdents+0xf1/0x270 fs/readdir.c:304
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f010ad9ce59
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f010bc0f028 EFLAGS: 00000246 ORIG_RAX: 000000000000004e
RAX: ffffffffffffffda RBX: 00007f010b015fa0 RCX: 00007f010ad9ce59
RDX: 0000000000000054 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00007f010ae32d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f010b016038 R14: 00007f010b015fa0 R15: 00007ffd93577348
 </TASK>

Allocated by task 5064:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __do_kmalloc_node mm/slub.c:5296 [inline]
 __kmalloc_noprof+0x35c/0x760 mm/slub.c:5308
 kmalloc_noprof include/linux/slab.h:954 [inline]
 kzalloc_noprof include/linux/slab.h:1188 [inline]
 tomoyo_encode2 security/tomoyo/realpath.c:45 [inline]
 tomoyo_encode+0x28b/0x550 security/tomoyo/realpath.c:80
 tomoyo_realpath_from_path+0x58d/0x5d0 security/tomoyo/realpath.c:283
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_path_perm+0x283/0x560 security/tomoyo/file.c:827
 security_inode_getattr+0x12b/0x310 security/security.c:1895
 vfs_getattr fs/stat.c:259 [inline]
 vfs_fstat fs/stat.c:281 [inline]
 vfs_fstatat+0xb4/0x170 fs/stat.c:371
 __do_sys_newfstatat fs/stat.c:538 [inline]
 __se_sys_newfstatat fs/stat.c:532 [inline]
 __x64_sys_newfstatat+0x151/0x200 fs/stat.c:532
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 5064:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2689 [inline]
 slab_free mm/slub.c:6251 [inline]
 kfree+0x1c5/0x640 mm/slub.c:6566
 tomoyo_path_perm+0x403/0x560 security/tomoyo/file.c:847
 security_inode_getattr+0x12b/0x310 security/security.c:1895
 vfs_getattr fs/stat.c:259 [inline]
 vfs_fstat fs/stat.c:281 [inline]
 vfs_fstatat+0xb4/0x170 fs/stat.c:371
 __do_sys_newfstatat fs/stat.c:538 [inline]
 __se_sys_newfstatat fs/stat.c:532 [inline]
 __x64_sys_newfstatat+0x151/0x200 fs/stat.c:532
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88816fee8800
 which belongs to the cache kmalloc-64 of size 64
The buggy address is located 37 bytes inside of
 freed 64-byte region [ffff88816fee8800, ffff88816fee8840)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x16fee8
flags: 0x57ff00000000000(node=1|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 057ff00000000000 ffff8881000418c0 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800200020 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 21294026082, free_ts 0
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x22d/0x280 mm/page_alloc.c:1853
 prep_new_page mm/page_alloc.c:1861 [inline]
 get_page_from_freelist+0x2593/0x2610 mm/page_alloc.c:3941
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5221
 alloc_slab_page mm/slub.c:3278 [inline]
 allocate_slab+0x77/0x660 mm/slub.c:3467
 new_slab mm/slub.c:3525 [inline]
 refill_objects+0x339/0x3d0 mm/slub.c:7272
 refill_sheaf mm/slub.c:2816 [inline]
 __pcs_replace_empty_main+0x321/0x720 mm/slub.c:4652
 alloc_from_pcs mm/slub.c:4750 [inline]
 slab_alloc_node mm/slub.c:4884 [inline]
 __do_kmalloc_node mm/slub.c:5295 [inline]
 __kmalloc_noprof+0x474/0x760 mm/slub.c:5308
 kmalloc_noprof include/linux/slab.h:954 [inline]
 kzalloc_noprof include/linux/slab.h:1188 [inline]
 handler_new_ref+0x261/0x9c0 drivers/media/v4l2-core/v4l2-ctrls-core.c:1882
 v4l2_ctrl_add_handler+0x19f/0x290 drivers/media/v4l2-core/v4l2-ctrls-core.c:2443
 vivid_create_controls+0x332d/0x3bd0 drivers/media/test-drivers/vivid/vivid-ctrls.c:2072
 vivid_create_instance drivers/media/test-drivers/vivid/vivid-core.c:1933 [inline]
 vivid_probe+0x4261/0x72b0 drivers/media/test-drivers/vivid/vivid-core.c:2095
 platform_probe+0xf9/0x190 drivers/base/platform.c:1432
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x267/0xaf0 drivers/base/dd.c:709
 __driver_probe_device+0x1ef/0x380 drivers/base/dd.c:871
 driver_probe_device+0x4f/0x240 drivers/base/dd.c:901
 __driver_attach+0x34c/0x640 drivers/base/dd.c:1295
page_owner free stack trace missing

Memory state around the buggy address:
 ffff88816fee8700: 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc
 ffff88816fee8780: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
>ffff88816fee8800: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
                               ^
 ffff88816fee8880: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff88816fee8900: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
==================================================================


***

KASAN: use-after-free Read in __ext4_check_dir_entry

tree:      torvalds
URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux
base:      9716c086c8e8b141d35aa61f2e96a2e83de212a7
arch:      amd64
compiler:  Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
config:    https://ci.syzbot.org/builds/ddf6ee7c-dfa8-4383-b004-10140edc081c/config
syz repro: https://ci.syzbot.org/findings/57c0b75a-8922-4dc1-9a20-ca947564792b/syz_repro

==================================================================
BUG: KASAN: use-after-free in ext4_dirent_get_data_len fs/ext4/ext4.h:4069 [inline]
BUG: KASAN: use-after-free in ext4_dir_entry_len fs/ext4/ext4.h:4096 [inline]
BUG: KASAN: use-after-free in __ext4_check_dir_entry+0x65a/0xc40 fs/ext4/dir.c:96
Read of size 1 at addr ffff88816be85045 by task syz.2.21/5880

CPU: 1 UID: 0 PID: 5880 Comm: syz.2.21 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description+0x55/0x1e0 mm/kasan/report.c:378
 print_report+0x58/0x70 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 ext4_dirent_get_data_len fs/ext4/ext4.h:4069 [inline]
 ext4_dir_entry_len fs/ext4/ext4.h:4096 [inline]
 __ext4_check_dir_entry+0x65a/0xc40 fs/ext4/dir.c:96
 ext4_find_dest_de+0x136/0x770 fs/ext4/namei.c:2203
 ext4_add_dirent_to_inline+0xcf/0x430 fs/ext4/inline.c:984
 ext4_try_add_inline_entry+0x235/0x8e0 fs/ext4/inline.c:1213
 __ext4_add_entry+0x390/0x1f40 fs/ext4/namei.c:2529
 ext4_add_entry fs/ext4/namei.c:2613 [inline]
 ext4_add_nondir+0x111/0x310 fs/ext4/namei.c:2936
 ext4_create+0x2e9/0x470 fs/ext4/namei.c:2982
 lookup_open fs/namei.c:4511 [inline]
 open_last_lookups fs/namei.c:4611 [inline]
 path_openat+0x1395/0x3860 fs/namei.c:4855
 do_file_open+0x23e/0x4a0 fs/namei.c:4887
 do_sys_openat2+0x113/0x200 fs/open.c:1364
 do_sys_open fs/open.c:1370 [inline]
 __do_sys_openat fs/open.c:1386 [inline]
 __se_sys_openat fs/open.c:1381 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1381
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5713b9ce59
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff672b25f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f5713e15fa0 RCX: 00007f5713b9ce59
RDX: 0000000000042042 RSI: 0000200000000080 RDI: 0000000000000004
RBP: 00007f5713c32d6f R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000014a R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5713e15fac R14: 00007f5713e15fa0 R15: 00007f5713e15fa0
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x16be85
flags: 0x57ff00000000000(node=1|zone=2|lastcpupid=0x7ff)
page_type: f0(buddy)
raw: 057ff00000000000 ffffea0005afa0c8 ffffea0005afa1c8 0000000000000000
raw: 0000000000000000 0000000000000000 00000000f0000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 0, migratetype Unmovable, gfp_mask 0xcc0(GFP_KERNEL), pid 5630, tgid 5630 (syz-executor), ts 67290853657, free_ts 69321168948
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x22d/0x280 mm/page_alloc.c:1853
 prep_new_page mm/page_alloc.c:1861 [inline]
 get_page_from_freelist+0x2593/0x2610 mm/page_alloc.c:3941
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5221
 __alloc_pages_noprof+0x10/0x100 mm/page_alloc.c:5255
 alloc_pages_bulk_noprof+0x5ff/0x7c0 mm/page_alloc.c:5175
 ___alloc_pages_bulk mm/kasan/shadow.c:345 [inline]
 __kasan_populate_vmalloc_do mm/kasan/shadow.c:370 [inline]
 __kasan_populate_vmalloc+0xc1/0x1d0 mm/kasan/shadow.c:424
 kasan_populate_vmalloc include/linux/kasan.h:580 [inline]
 alloc_vmap_area+0xd47/0x1480 mm/vmalloc.c:2123
 __get_vm_area_node+0x1f8/0x300 mm/vmalloc.c:3226
 __vmalloc_node_range_noprof+0x36a/0x1750 mm/vmalloc.c:4024
 vmalloc_user_noprof+0xad/0xe0 mm/vmalloc.c:4218
 kcov_ioctl+0x55/0x620 kernel/kcov.c:726
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 5693 tgid 5693 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1397 [inline]
 __free_frozen_pages+0xc1c/0xd30 mm/page_alloc.c:2938
 kasan_depopulate_vmalloc_pte+0x6d/0x90 mm/kasan/shadow.c:484
 apply_to_pte_range mm/memory.c:3338 [inline]
 apply_to_pmd_range mm/memory.c:3382 [inline]
 apply_to_pud_range mm/memory.c:3418 [inline]
 apply_to_p4d_range mm/memory.c:3454 [inline]
 __apply_to_page_range+0xbdc/0x1420 mm/memory.c:3490
 __kasan_release_vmalloc+0xa2/0xd0 mm/kasan/shadow.c:602
 kasan_release_vmalloc include/linux/kasan.h:593 [inline]
 kasan_release_vmalloc_node mm/vmalloc.c:2284 [inline]
 purge_vmap_node+0x220/0x960 mm/vmalloc.c:2306
 __purge_vmap_area_lazy+0x779/0xb40 mm/vmalloc.c:2396
 drain_vmap_area_work+0x27/0x40 mm/vmalloc.c:2430
 process_one_work kernel/workqueue.c:3314 [inline]
 process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3397
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3478
 kthread+0x389/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Memory state around the buggy address:
 ffff88816be84f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88816be84f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88816be85000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                           ^
 ffff88816be85080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88816be85100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================


***

If these findings have caused you to resend the series or submit a
separate fix, please add the following tag to your commit message:
  Tested-by: syzbot@syzkaller.appspotmail.com

---
This report is generated by a bot. It may contain errors.
syzbot ci engineers can be reached at syzkaller@googlegroups.com.

To test a patch for this bug, please reply with `#syz test`
(should be on a separate line).

The patch should be attached to the email.
Note: arguments like custom git repos and branches are not supported.

The email will later be sent to:
[adilger.kernel@dilger.ca adilger@dilger.ca adilger@diliger.ca artem.blagodarenko@gmail.com linux-ext4@vger.kernel.org pravin.shelar@sun.com]

If the report looks fine to you, reply with:
#syz upstream

If the report is a false positive, reply with
#syz invalid


^ permalink raw reply	[flat|nested] 6+ messages in thread
* [moderation/CI] Re: Data in direntry (dirdata) feature
@ 2026-06-19 23:25 syzbot ci
  2026-06-20  6:53 ` Aleksandr Nogikh
  0 siblings, 1 reply; 6+ messages in thread
From: syzbot ci @ 2026-06-19 23:25 UTC (permalink / raw)
  To: syzkaller-upstream-moderation; +Cc: syzbot

syzbot ci has tested the following series

[v3] Data in direntry (dirdata) feature
https://lore.kernel.org/all/20260619191022.27008-1-ablagodarenko@thelustrecollective.com
* [PATCH v3 01/10] ext4: replace ext4_dir_entry with ext4_dir_entry_2
* [PATCH v3 02/10] ext4: add ext4_dir_entry_is_tail()
* [PATCH v3 03/10] ext4: refactor dx_root to support variable dirent sizes
* [PATCH v3 04/10] ext4: add dirdata format definitions and access helpers
* [PATCH v3 05/10] ext4: preserve dirdata bits in get_dtype()
* [PATCH v3 06/10] ext4: add ext4_dir_entry_len() and harden dirdata parsing
* [PATCH v3 07/10] ext4: rename ext4_dir_rec_len() and clarify dirdata usage
* [PATCH v3 08/10] ext4: dirdata feature
* [PATCH v3 09/10] ext4: add dirdata set/get helpers
* [PATCH v3 10/10] ext4: Add EXT4_IOC_SET_LUFID ioctl for setting LUFID on directory entries

and found the following issues:
* KASAN: slab-out-of-bounds Read in __ext4_check_dir_entry
* KASAN: slab-out-of-bounds Read in ext4_inlinedir_to_tree
* KASAN: slab-use-after-free Read in __ext4_check_dir_entry
* KASAN: slab-use-after-free Read in ext4_inlinedir_to_tree
* KASAN: use-after-free Read in __ext4_check_dir_entry

Full report is available here:
https://ci.syzbot.org/series/a3c6e513-a6eb-4583-86f6-89176398b397

***

KASAN: slab-out-of-bounds Read in __ext4_check_dir_entry

tree:      torvalds
URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux
base:      08c7183f5b9ffe4408e74fff848a4cc2105361d4
arch:      amd64
compiler:  Debian clang version 22.1.6 (++20260514074242+fc4aad7b5db3-1~exp1~20260514074407.73), Debian LLD 22.1.6
config:    https://ci.syzbot.org/builds/0efdb868-daeb-4649-9bcb-5af41d993e73/config
syz repro: https://ci.syzbot.org/findings/ec557d64-7b60-46c9-a0eb-feaa7a3eb2cd/syz_repro

loop0: lost filesystem error report for type 5 error -117
EXT4-fs (loop0): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: none.
==================================================================
BUG: KASAN: slab-out-of-bounds in ext4_dirent_get_data_len fs/ext4/ext4.h:4156 [inline]
BUG: KASAN: slab-out-of-bounds in ext4_dir_entry_len fs/ext4/ext4.h:4183 [inline]
BUG: KASAN: slab-out-of-bounds in __ext4_check_dir_entry+0x659/0xbe0 fs/ext4/dir.c:96
Read of size 1 at addr ffff88816e86bcd9 by task syz.0.21/5783

CPU: 1 UID: 0 PID: 5783 Comm: syz.0.21 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description+0x55/0x1e0 mm/kasan/report.c:378
 print_report+0x58/0x70 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 ext4_dirent_get_data_len fs/ext4/ext4.h:4156 [inline]
 ext4_dir_entry_len fs/ext4/ext4.h:4183 [inline]
 __ext4_check_dir_entry+0x659/0xbe0 fs/ext4/dir.c:96
 ext4_check_all_de+0x6a/0x140 fs/ext4/dir.c:657
 ext4_convert_inline_data_nolock+0x1b7/0x980 fs/ext4/inline.c:1121
 ext4_try_add_inline_entry+0x5cc/0x8a0 fs/ext4/inline.c:1247
 __ext4_add_entry+0x385/0x3470 fs/ext4/namei.c:2552
 ext4_add_entry fs/ext4/namei.c:2636 [inline]
 ext4_mkdir+0x5f3/0xd30 fs/ext4/namei.c:3203
 vfs_mkdir+0x406/0x620 fs/namei.c:5272
 filename_mkdirat+0x285/0x510 fs/namei.c:5305
 __do_sys_mkdirat fs/namei.c:5326 [inline]
 __se_sys_mkdirat+0x35/0x150 fs/namei.c:5323
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb4c839ce59
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd4b254a88 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007fb4c8615fa0 RCX: 00007fb4c839ce59
RDX: 0000000000000037 RSI: 0000200000000380 RDI: 0000000000000004
RBP: 00007fb4c8432e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb4c8615fac R14: 00007fb4c8615fa0 R15: 00007fb4c8615fa0
 </TASK>

Allocated by task 5056:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __kmalloc_cache_noprof+0x318/0x660 mm/slub.c:5451
 _kmalloc_noprof include/linux/slab.h:969 [inline]
 _kzalloc_noprof include/linux/slab.h:1286 [inline]
 kernfs_get_open_node fs/kernfs/file.c:536 [inline]
 kernfs_fop_open+0x7e6/0xce0 fs/kernfs/file.c:711
 do_dentry_open+0x816/0x1380 fs/open.c:947
 vfs_open+0x3b/0x340 fs/open.c:1079
 do_open fs/namei.c:4700 [inline]
 path_openat+0x2e44/0x3830 fs/namei.c:4859
 do_file_open+0x23e/0x4a0 fs/namei.c:4888
 do_sys_openat2+0x115/0x200 fs/open.c:1395
 do_sys_open fs/open.c:1401 [inline]
 __do_sys_openat fs/open.c:1417 [inline]
 __se_sys_openat fs/open.c:1412 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1412
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88816e86bc00
 which belongs to the cache kmalloc-128 of size 128
The buggy address is located 89 bytes to the right of
 allocated 128-byte region [ffff88816e86bc00, ffff88816e86bc80)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88816e86bf00 pfn:0x16e86b
flags: 0x57ff00000000200(workingset|node=1|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 057ff00000000200 ffff888100041a00 ffff888160400648 ffff888160400648
raw: ffff88816e86bf00 000000080010000f 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5056, tgid 5056 (udevd), ts 53238350188, free_ts 53091667410
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x22d/0x280 mm/page_alloc.c:1853
 prep_new_page mm/page_alloc.c:1861 [inline]
 get_page_from_freelist+0x24ae/0x2530 mm/page_alloc.c:3941
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5221
 alloc_slab_page mm/slub.c:3289 [inline]
 allocate_slab+0x74/0x5d0 mm/slub.c:3404
 new_slab mm/slub.c:3447 [inline]
 refill_objects+0x328/0x3c0 mm/slub.c:7241
 refill_sheaf mm/slub.c:2827 [inline]
 __pcs_replace_empty_main+0x2e0/0x6b0 mm/slub.c:4692
 alloc_from_pcs mm/slub.c:4790 [inline]
 slab_alloc_node mm/slub.c:4924 [inline]
 __kmalloc_cache_noprof+0x388/0x660 mm/slub.c:5446
 _kmalloc_noprof include/linux/slab.h:969 [inline]
 _kzalloc_noprof include/linux/slab.h:1286 [inline]
 kernfs_get_open_node fs/kernfs/file.c:536 [inline]
 kernfs_fop_open+0x7e6/0xce0 fs/kernfs/file.c:711
 do_dentry_open+0x816/0x1380 fs/open.c:947
 vfs_open+0x3b/0x340 fs/open.c:1079
 do_open fs/namei.c:4700 [inline]
 path_openat+0x2e44/0x3830 fs/namei.c:4859
 do_file_open+0x23e/0x4a0 fs/namei.c:4888
 do_sys_openat2+0x115/0x200 fs/open.c:1395
 do_sys_open fs/open.c:1401 [inline]
 __do_sys_openat fs/open.c:1417 [inline]
 __se_sys_openat fs/open.c:1412 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1412
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 23 tgid 23 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1397 [inline]
 __free_frozen_pages+0xc0d/0xd20 mm/page_alloc.c:2938
 __tlb_remove_table_free mm/mmu_gather.c:228 [inline]
 tlb_remove_table_rcu+0x85/0x100 mm/mmu_gather.c:291
 rcu_do_batch kernel/rcu/tree.c:2645 [inline]
 rcu_core+0x78b/0x10a0 kernel/rcu/tree.c:2897
 handle_softirqs+0x225/0x840 kernel/softirq.c:622
 run_ksoftirqd+0x36/0x60 kernel/softirq.c:1076
 smpboot_thread_fn+0x57c/0xa80 kernel/smpboot.c:160
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Memory state around the buggy address:
 ffff88816e86bb80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88816e86bc00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88816e86bc80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                                                    ^
 ffff88816e86bd00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88816e86bd80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


***

KASAN: slab-out-of-bounds Read in ext4_inlinedir_to_tree

tree:      torvalds
URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux
base:      08c7183f5b9ffe4408e74fff848a4cc2105361d4
arch:      amd64
compiler:  Debian clang version 22.1.6 (++20260514074242+fc4aad7b5db3-1~exp1~20260514074407.73), Debian LLD 22.1.6
config:    https://ci.syzbot.org/builds/0efdb868-daeb-4649-9bcb-5af41d993e73/config
syz repro: https://ci.syzbot.org/findings/bb78d414-4cff-400b-aaf6-76d450b12cda/syz_repro

==================================================================
BUG: KASAN: slab-out-of-bounds in ext4_dir_entry_len fs/ext4/ext4.h:4182 [inline]
BUG: KASAN: slab-out-of-bounds in ext4_inlinedir_to_tree+0xd95/0x10a0 fs/ext4/inline.c:1335
Read of size 2 at addr ffff88816f219a3c by task syz.1.18/5830

CPU: 1 UID: 0 PID: 5830 Comm: syz.1.18 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description+0x55/0x1e0 mm/kasan/report.c:378
 print_report+0x58/0x70 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 ext4_dir_entry_len fs/ext4/ext4.h:4182 [inline]
 ext4_inlinedir_to_tree+0xd95/0x10a0 fs/ext4/inline.c:1335
 ext4_htree_fill_tree+0x4c9/0x2480 fs/ext4/namei.c:1195
 ext4_dx_readdir fs/ext4/dir.c:600 [inline]
 ext4_readdir+0x2e2a/0x3720 fs/ext4/dir.c:146
 iterate_dir+0x2e2/0x4d0 fs/readdir.c:110
 __do_sys_getdents fs/readdir.c:319 [inline]
 __se_sys_getdents+0xf1/0x270 fs/readdir.c:304
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe51459ce59
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fe515527028 EFLAGS: 00000246 ORIG_RAX: 000000000000004e
RAX: ffffffffffffffda RBX: 00007fe514815fa0 RCX: 00007fe51459ce59
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000006
RBP: 00007fe514632e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe514816038 R14: 00007fe514815fa0 R15: 00007fffd9b381d8
 </TASK>

Allocated by task 5830:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __do_kmalloc_node mm/slub.c:5334 [inline]
 __kmalloc_noprof+0x358/0x750 mm/slub.c:5347
 _kmalloc_noprof include/linux/slab.h:973 [inline]
 ext4_inlinedir_to_tree+0x2ec/0x10a0 fs/ext4/inline.c:1292
 ext4_htree_fill_tree+0x4c9/0x2480 fs/ext4/namei.c:1195
 ext4_dx_readdir fs/ext4/dir.c:600 [inline]
 ext4_readdir+0x2e2a/0x3720 fs/ext4/dir.c:146
 iterate_dir+0x2e2/0x4d0 fs/readdir.c:110
 __do_sys_getdents fs/readdir.c:319 [inline]
 __se_sys_getdents+0xf1/0x270 fs/readdir.c:304
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88816f219a00
 which belongs to the cache kmalloc-64 of size 64
The buggy address is located 0 bytes to the right of
 allocated 60-byte region [ffff88816f219a00, ffff88816f219a3c)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x16f219
flags: 0x57ff00000000000(node=1|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 057ff00000000000 ffff8881000418c0 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800200020 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 10138712683, free_ts 10137977139
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x22d/0x280 mm/page_alloc.c:1853
 prep_new_page mm/page_alloc.c:1861 [inline]
 get_page_from_freelist+0x24ae/0x2530 mm/page_alloc.c:3941
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5221
 alloc_slab_page mm/slub.c:3289 [inline]
 allocate_slab+0x74/0x5d0 mm/slub.c:3404
 new_slab mm/slub.c:3447 [inline]
 refill_objects+0x328/0x3c0 mm/slub.c:7241
 refill_sheaf mm/slub.c:2827 [inline]
 __pcs_replace_empty_main+0x2e0/0x6b0 mm/slub.c:4692
 alloc_from_pcs mm/slub.c:4790 [inline]
 slab_alloc_node mm/slub.c:4924 [inline]
 __do_kmalloc_node mm/slub.c:5333 [inline]
 __kmalloc_noprof+0x464/0x750 mm/slub.c:5347
 _kmalloc_noprof include/linux/slab.h:973 [inline]
 _kzalloc_noprof include/linux/slab.h:1286 [inline]
 kobject_get_path+0xc5/0x2f0 lib/kobject.c:161
 kobject_uevent_env+0x29e/0x9e0 lib/kobject_uevent.c:548
 device_add+0x544/0xb80 drivers/base/core.c:3738
 scsi_add_host_with_dma+0x5db/0xd00 drivers/scsi/hosts.c:287
 ata_scsi_add_hosts+0x29b/0x4b0 drivers/ata/libata-scsi.c:4659
 ata_host_register+0x1c5/0x7d0 drivers/ata/libata-core.c:6131
 ata_host_activate+0x33c/0x3c0 drivers/ata/libata-core.c:6234
 ahci_init_one+0x1afa/0x22b0 drivers/ata/ahci.c:3090
 local_pci_probe drivers/pci/pci-driver.c:332 [inline]
 pci_call_probe drivers/pci/pci-driver.c:394 [inline]
 __pci_device_probe drivers/pci/pci-driver.c:455 [inline]
 pci_device_probe+0x431/0xc90 drivers/pci/pci-driver.c:489
page last free pid 36 tgid 36 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1397 [inline]
 __free_frozen_pages+0xc0d/0xd20 mm/page_alloc.c:2938
 __kasan_populate_vmalloc_do mm/kasan/shadow.c:393 [inline]
 __kasan_populate_vmalloc+0x1a8/0x1c0 mm/kasan/shadow.c:424
 kasan_populate_vmalloc include/linux/kasan.h:580 [inline]
 alloc_vmap_area+0xd1a/0x1420 mm/vmalloc.c:2123
 __get_vm_area_node+0x1f2/0x300 mm/vmalloc.c:3226
 __vmalloc_node_range_noprof+0x358/0x1730 mm/vmalloc.c:4024
 __vmalloc_node_noprof+0xc2/0x100 mm/vmalloc.c:4124
 alloc_thread_stack_node kernel/fork.c:358 [inline]
 dup_task_struct+0x28e/0x850 kernel/fork.c:928
 copy_process+0x81b/0x42e0 kernel/fork.c:2109
 kernel_clone+0x2d7/0x940 kernel/fork.c:2745
 user_mode_thread+0x110/0x180 kernel/fork.c:2821
 call_usermodehelper_exec_work+0x5c/0x230 kernel/umh.c:171
 process_one_work kernel/workqueue.c:3322 [inline]
 process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Memory state around the buggy address:
 ffff88816f219900: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
 ffff88816f219980: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
>ffff88816f219a00: 00 00 00 00 00 00 00 04 fc fc fc fc fc fc fc fc
                                        ^
 ffff88816f219a80: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff88816f219b00: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
==================================================================


***

KASAN: slab-use-after-free Read in __ext4_check_dir_entry

tree:      torvalds
URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux
base:      08c7183f5b9ffe4408e74fff848a4cc2105361d4
arch:      amd64
compiler:  Debian clang version 22.1.6 (++20260514074242+fc4aad7b5db3-1~exp1~20260514074407.73), Debian LLD 22.1.6
config:    https://ci.syzbot.org/builds/0efdb868-daeb-4649-9bcb-5af41d993e73/config
syz repro: https://ci.syzbot.org/findings/f322e293-7a3f-469a-ae1f-677c84eb4c0f/syz_repro

==================================================================
BUG: KASAN: slab-use-after-free in ext4_dirent_get_data_len fs/ext4/ext4.h:4156 [inline]
BUG: KASAN: slab-use-after-free in ext4_dir_entry_len fs/ext4/ext4.h:4183 [inline]
BUG: KASAN: slab-use-after-free in __ext4_check_dir_entry+0x659/0xbe0 fs/ext4/dir.c:96
Read of size 1 at addr ffff888103e89c1d by task syz.2.19/5867

CPU: 0 UID: 0 PID: 5867 Comm: syz.2.19 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description+0x55/0x1e0 mm/kasan/report.c:378
 print_report+0x58/0x70 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 ext4_dirent_get_data_len fs/ext4/ext4.h:4156 [inline]
 ext4_dir_entry_len fs/ext4/ext4.h:4183 [inline]
 __ext4_check_dir_entry+0x659/0xbe0 fs/ext4/dir.c:96
 ext4_check_all_de+0x6a/0x140 fs/ext4/dir.c:657
 ext4_convert_inline_data_nolock+0x1b7/0x980 fs/ext4/inline.c:1121
 ext4_try_add_inline_entry+0x5cc/0x8a0 fs/ext4/inline.c:1247
 __ext4_add_entry+0x385/0x3470 fs/ext4/namei.c:2552
 ext4_add_entry fs/ext4/namei.c:2636 [inline]
 ext4_mkdir+0x5f3/0xd30 fs/ext4/namei.c:3203
 vfs_mkdir+0x406/0x620 fs/namei.c:5272
 filename_mkdirat+0x285/0x510 fs/namei.c:5305
 __do_sys_mkdirat fs/namei.c:5326 [inline]
 __se_sys_mkdirat+0x35/0x150 fs/namei.c:5323
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb01d39ce59
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fb01e269028 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007fb01d615fa0 RCX: 00007fb01d39ce59
RDX: 0000000000000037 RSI: 0000200000000380 RDI: 0000000000000004
RBP: 00007fb01d432e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb01d616038 R14: 00007fb01d615fa0 R15: 00007ffdec822cc8
 </TASK>

Allocated by task 5630:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __kmalloc_cache_noprof+0x318/0x660 mm/slub.c:5451
 _kmalloc_noprof include/linux/slab.h:969 [inline]
 __hw_addr_create+0x62/0x240 net/core/dev_addr_lists.c:69
 __hw_addr_add_ex+0x1ce/0x520 net/core/dev_addr_lists.c:127
 __hw_addr_add net/core/dev_addr_lists.c:144 [inline]
 dev_addr_init+0x15a/0x240 net/core/dev_addr_lists.c:696
 alloc_netdev_mqs+0x2b4/0x1270 net/core/dev.c:12064
 __ip_tunnel_create+0x348/0x560 net/ipv4/ip_tunnel.c:255
 ip_tunnel_init_net+0x2ea/0x810 net/ipv4/ip_tunnel.c:1150
 ops_init+0x35d/0x5d0 net/core/net_namespace.c:137
 setup_net+0x118/0x350 net/core/net_namespace.c:446
 copy_net_ns+0x4f9/0x720 net/core/net_namespace.c:579
 create_new_namespaces+0x3f0/0x6b0 kernel/nsproxy.c:132
 unshare_nsproxy_namespaces+0x149/0x190 kernel/nsproxy.c:234
 ksys_unshare+0x57d/0xa00 kernel/fork.c:3266
 __do_sys_unshare kernel/fork.c:3340 [inline]
 __se_sys_unshare kernel/fork.c:3338 [inline]
 __x64_sys_unshare+0x38/0x50 kernel/fork.c:3338
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 68:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2700 [inline]
 slab_free_freelist_hook mm/slub.c:2729 [inline]
 slab_free_bulk mm/slub.c:6344 [inline]
 kmem_cache_free_bulk+0x30f/0x1180 mm/slub.c:7076
 kfree_bulk include/linux/slab.h:891 [inline]
 kvfree_rcu_bulk+0xc6/0x190 mm/slab_common.c:1502
 kvfree_rcu_drain_ready mm/slab_common.c:1704 [inline]
 kfree_rcu_monitor+0x21a/0x2b0 mm/slab_common.c:1777
 process_one_work kernel/workqueue.c:3322 [inline]
 process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Last potentially related work creation:
 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57
 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556
 kvfree_call_rcu+0x100/0x430 mm/slab_common.c:1970
 __hw_addr_flush net/core/dev_addr_lists.c:500 [inline]
 dev_addr_flush+0x16c/0x210 net/core/dev_addr_lists.c:673
 free_netdev+0x26c/0x6e0 net/core/dev.c:12209
 netdev_run_todo+0xf3d/0x10d0 net/core/dev.c:11743
 ops_exit_rtnl_list net/core/net_namespace.c:189 [inline]
 ops_undo_list+0x396/0x8d0 net/core/net_namespace.c:248
 cleanup_net+0x572/0x810 net/core/net_namespace.c:702
 process_one_work kernel/workqueue.c:3322 [inline]
 process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

The buggy address belongs to the object at ffff888103e89c00
 which belongs to the cache kmalloc-128 of size 128
The buggy address is located 29 bytes inside of
 freed 128-byte region [ffff888103e89c00, ffff888103e89c80)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x103e89
flags: 0x17ff00000000000(node=0|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 017ff00000000000 ffff888100041a00 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800100010 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 2773920656, free_ts 0
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x22d/0x280 mm/page_alloc.c:1853
 prep_new_page mm/page_alloc.c:1861 [inline]
 get_page_from_freelist+0x24ae/0x2530 mm/page_alloc.c:3941
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5221
 alloc_slab_page mm/slub.c:3289 [inline]
 allocate_slab+0x74/0x5d0 mm/slub.c:3404
 new_slab mm/slub.c:3447 [inline]
 refill_objects+0x328/0x3c0 mm/slub.c:7241
 refill_sheaf mm/slub.c:2827 [inline]
 __pcs_replace_empty_main+0x2e0/0x6b0 mm/slub.c:4692
 alloc_from_pcs mm/slub.c:4790 [inline]
 slab_alloc_node mm/slub.c:4924 [inline]
 __do_kmalloc_node mm/slub.c:5333 [inline]
 __kmalloc_noprof+0x464/0x750 mm/slub.c:5347
 _kmalloc_noprof include/linux/slab.h:973 [inline]
 _kzalloc_noprof include/linux/slab.h:1286 [inline]
 __alloc_empty_sheaf+0x24/0x40 mm/slub.c:2774
 alloc_empty_sheaf mm/slub.c:2794 [inline]
 __pcs_replace_empty_main+0x447/0x6b0 mm/slub.c:4687
 alloc_from_pcs mm/slub.c:4790 [inline]
 slab_alloc_node mm/slub.c:4924 [inline]
 kmem_cache_alloc_lru_noprof+0x372/0x640 mm/slub.c:4958
 alloc_inode+0x6a/0x1b0 fs/inode.c:341
 new_inode+0x1f/0x170 fs/inode.c:1177
 debugfs_get_inode fs/debugfs/inode.c:72 [inline]
 debugfs_create_dir+0x68/0x350 fs/debugfs/inode.c:578
 blk_dev_init+0xdf/0x150 block/blk-core.c:1333
 genhd_device_init+0x1c/0x50 block/genhd.c:1002
 do_one_initcall+0x250/0x870 init/main.c:1347
page_owner free stack trace missing

Memory state around the buggy address:
 ffff888103e89b00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888103e89b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888103e89c00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff888103e89c80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888103e89d00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


***

KASAN: slab-use-after-free Read in ext4_inlinedir_to_tree

tree:      torvalds
URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux
base:      08c7183f5b9ffe4408e74fff848a4cc2105361d4
arch:      amd64
compiler:  Debian clang version 22.1.6 (++20260514074242+fc4aad7b5db3-1~exp1~20260514074407.73), Debian LLD 22.1.6
config:    https://ci.syzbot.org/builds/0efdb868-daeb-4649-9bcb-5af41d993e73/config
syz repro: https://ci.syzbot.org/findings/b1e2a550-a6c3-410a-ae53-ca1e5366cc94/syz_repro

loop0: lost filesystem error report for type 5 error -117
EXT4-fs (loop0): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: none.
==================================================================
BUG: KASAN: slab-use-after-free in ext4_dirent_get_data_len fs/ext4/ext4.h:4156 [inline]
BUG: KASAN: slab-use-after-free in ext4_dir_entry_len fs/ext4/ext4.h:4183 [inline]
BUG: KASAN: slab-use-after-free in ext4_inlinedir_to_tree+0x8f0/0x10a0 fs/ext4/inline.c:1335
Read of size 1 at addr ffff888111d0149d by task syz.0.19/5801

CPU: 1 UID: 0 PID: 5801 Comm: syz.0.19 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description+0x55/0x1e0 mm/kasan/report.c:378
 print_report+0x58/0x70 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 ext4_dirent_get_data_len fs/ext4/ext4.h:4156 [inline]
 ext4_dir_entry_len fs/ext4/ext4.h:4183 [inline]
 ext4_inlinedir_to_tree+0x8f0/0x10a0 fs/ext4/inline.c:1335
 ext4_htree_fill_tree+0x4c9/0x2480 fs/ext4/namei.c:1195
 ext4_dx_readdir fs/ext4/dir.c:600 [inline]
 ext4_readdir+0x2e2a/0x3720 fs/ext4/dir.c:146
 iterate_dir+0x2e2/0x4d0 fs/readdir.c:110
 __do_sys_getdents fs/readdir.c:319 [inline]
 __se_sys_getdents+0xf1/0x270 fs/readdir.c:304
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f6e8459ce59
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffef0bce788 EFLAGS: 00000246 ORIG_RAX: 000000000000004e
RAX: ffffffffffffffda RBX: 00007f6e84815fa0 RCX: 00007f6e8459ce59
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00007f6e84632e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6e84815fac R14: 00007f6e84815fa0 R15: 00007f6e84815fa0
 </TASK>

Allocated by task 5738:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __kmalloc_cache_noprof+0x318/0x660 mm/slub.c:5451
 _kmalloc_noprof include/linux/slab.h:969 [inline]
 __kthread_create_on_node+0x115/0x3d0 kernel/kthread.c:483
 kthread_create_on_node+0xeb/0x140 kernel/kthread.c:559
 napi_kthread_create net/core/dev.c:1656 [inline]
 netif_napi_add_weight_locked+0x699/0x940 net/core/dev.c:7594
 netif_napi_add_weight include/linux/netdevice.h:2870 [inline]
 netif_napi_add include/linux/netdevice.h:2887 [inline]
 wg_peer_create+0x52d/0x860 drivers/net/wireguard/peer.c:57
 set_peer drivers/net/wireguard/netlink.c:392 [inline]
 wg_set_device_doit+0xf3a/0x2120 drivers/net/wireguard/netlink.c:569
 genl_family_rcv_msg_doit+0x233/0x340 net/netlink/genetlink.c:1114
 genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline]
 genl_rcv_msg+0x614/0x7a0 net/netlink/genetlink.c:1209
 netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2556
 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218
 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
 netlink_unicast+0x7bb/0x940 net/netlink/af_netlink.c:1345
 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1900
 sock_sendmsg_nosec+0x13a/0x180 net/socket.c:775
 __sock_sendmsg net/socket.c:790 [inline]
 __sys_sendto+0x408/0x5a0 net/socket.c:2252
 __do_sys_sendto net/socket.c:2259 [inline]
 __se_sys_sendto net/socket.c:2255 [inline]
 __x64_sys_sendto+0xde/0x100 net/socket.c:2255
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 5738:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2700 [inline]
 slab_free mm/slub.c:6310 [inline]
 kfree+0x1c5/0x640 mm/slub.c:6625
 __kthread_create_on_node+0x2fe/0x3d0 kernel/kthread.c:523
 kthread_create_on_node+0xeb/0x140 kernel/kthread.c:559
 napi_kthread_create net/core/dev.c:1656 [inline]
 netif_napi_add_weight_locked+0x699/0x940 net/core/dev.c:7594
 netif_napi_add_weight include/linux/netdevice.h:2870 [inline]
 netif_napi_add include/linux/netdevice.h:2887 [inline]
 wg_peer_create+0x52d/0x860 drivers/net/wireguard/peer.c:57
 set_peer drivers/net/wireguard/netlink.c:392 [inline]
 wg_set_device_doit+0xf3a/0x2120 drivers/net/wireguard/netlink.c:569
 genl_family_rcv_msg_doit+0x233/0x340 net/netlink/genetlink.c:1114
 genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline]
 genl_rcv_msg+0x614/0x7a0 net/netlink/genetlink.c:1209
 netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2556
 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218
 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
 netlink_unicast+0x7bb/0x940 net/netlink/af_netlink.c:1345
 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1900
 sock_sendmsg_nosec+0x13a/0x180 net/socket.c:775
 __sock_sendmsg net/socket.c:790 [inline]
 __sys_sendto+0x408/0x5a0 net/socket.c:2252
 __do_sys_sendto net/socket.c:2259 [inline]
 __se_sys_sendto net/socket.c:2255 [inline]
 __x64_sys_sendto+0xde/0x100 net/socket.c:2255
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888111d01480
 which belongs to the cache kmalloc-64 of size 64
The buggy address is located 29 bytes inside of
 freed 64-byte region [ffff888111d01480, ffff888111d014c0)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x111d01
flags: 0x17ff00000000000(node=0|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 017ff00000000000 ffff8881000418c0 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800200020 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1113, tgid 1113 (kworker/u9:4), ts 18841797934, free_ts 18841792693
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x22d/0x280 mm/page_alloc.c:1853
 prep_new_page mm/page_alloc.c:1861 [inline]
 get_page_from_freelist+0x24ae/0x2530 mm/page_alloc.c:3941
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5221
 alloc_slab_page mm/slub.c:3289 [inline]
 allocate_slab+0x74/0x5d0 mm/slub.c:3404
 new_slab mm/slub.c:3447 [inline]
 refill_objects+0x328/0x3c0 mm/slub.c:7241
 refill_sheaf mm/slub.c:2827 [inline]
 __pcs_replace_empty_main+0x2e0/0x6b0 mm/slub.c:4692
 alloc_from_pcs mm/slub.c:4790 [inline]
 slab_alloc_node mm/slub.c:4924 [inline]
 __do_kmalloc_node mm/slub.c:5333 [inline]
 __kmalloc_node_noprof+0x56a/0x7b0 mm/slub.c:5340
 _kmalloc_node_noprof include/linux/slab.h:1174 [inline]
 __vmalloc_area_node mm/vmalloc.c:3857 [inline]
 __vmalloc_node_range_noprof+0x5d9/0x1730 mm/vmalloc.c:4064
 __vmalloc_node_noprof+0xc2/0x100 mm/vmalloc.c:4124
 alloc_thread_stack_node kernel/fork.c:358 [inline]
 dup_task_struct+0x28e/0x850 kernel/fork.c:928
 copy_process+0x81b/0x42e0 kernel/fork.c:2109
 kernel_clone+0x2d7/0x940 kernel/fork.c:2745
 user_mode_thread+0x110/0x180 kernel/fork.c:2821
 call_usermodehelper_exec_work+0x5c/0x230 kernel/umh.c:171
 process_one_work kernel/workqueue.c:3322 [inline]
 process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486
page last free pid 1113 tgid 1113 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1397 [inline]
 __free_frozen_pages+0xc0d/0xd20 mm/page_alloc.c:2938
 __kasan_populate_vmalloc_do mm/kasan/shadow.c:393 [inline]
 __kasan_populate_vmalloc+0x1a8/0x1c0 mm/kasan/shadow.c:424
 kasan_populate_vmalloc include/linux/kasan.h:580 [inline]
 alloc_vmap_area+0xd1a/0x1420 mm/vmalloc.c:2123
 __get_vm_area_node+0x1f2/0x300 mm/vmalloc.c:3226
 __vmalloc_node_range_noprof+0x358/0x1730 mm/vmalloc.c:4024
 __vmalloc_node_noprof+0xc2/0x100 mm/vmalloc.c:4124
 alloc_thread_stack_node kernel/fork.c:358 [inline]
 dup_task_struct+0x28e/0x850 kernel/fork.c:928
 copy_process+0x81b/0x42e0 kernel/fork.c:2109
 kernel_clone+0x2d7/0x940 kernel/fork.c:2745
 user_mode_thread+0x110/0x180 kernel/fork.c:2821
 call_usermodehelper_exec_work+0x5c/0x230 kernel/umh.c:171
 process_one_work kernel/workqueue.c:3322 [inline]
 process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Memory state around the buggy address:
 ffff888111d01380: 00 00 00 00 00 00 00 04 fc fc fc fc fc fc fc fc
 ffff888111d01400: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
>ffff888111d01480: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
                            ^
 ffff888111d01500: 00 00 00 00 00 00 02 fc fc fc fc fc fc fc fc fc
 ffff888111d01580: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
==================================================================


***

KASAN: use-after-free Read in __ext4_check_dir_entry

tree:      torvalds
URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux
base:      08c7183f5b9ffe4408e74fff848a4cc2105361d4
arch:      amd64
compiler:  Debian clang version 22.1.6 (++20260514074242+fc4aad7b5db3-1~exp1~20260514074407.73), Debian LLD 22.1.6
config:    https://ci.syzbot.org/builds/0efdb868-daeb-4649-9bcb-5af41d993e73/config
syz repro: https://ci.syzbot.org/findings/07c4f835-36f6-4535-a165-aa25c5af571c/syz_repro

EXT4-fs error (device loop2): ext4_inlinedir_to_tree:1343: inode #21: block 10: comm syz.2.19: path /: bad entry in directory: directory entry overrun - offset=20, inode=0, rec_len=1024, size=60 fake=0
==================================================================
BUG: KASAN: use-after-free in ext4_dirent_get_data_len fs/ext4/ext4.h:4156 [inline]
BUG: KASAN: use-after-free in ext4_dir_entry_len fs/ext4/ext4.h:4183 [inline]
BUG: KASAN: use-after-free in __ext4_check_dir_entry+0x659/0xbe0 fs/ext4/dir.c:96
Read of size 1 at addr ffff888112785045 by task syz.2.19/5869

CPU: 0 UID: 0 PID: 5869 Comm: syz.2.19 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description+0x55/0x1e0 mm/kasan/report.c:378
 print_report+0x58/0x70 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 ext4_dirent_get_data_len fs/ext4/ext4.h:4156 [inline]
 ext4_dir_entry_len fs/ext4/ext4.h:4183 [inline]
 __ext4_check_dir_entry+0x659/0xbe0 fs/ext4/dir.c:96
 ext4_find_dest_de+0x14e/0x6e0 fs/ext4/namei.c:2221
 ext4_add_dirent_to_inline+0xcc/0x410 fs/ext4/inline.c:984
 ext4_try_add_inline_entry+0x21e/0x8a0 fs/ext4/inline.c:1213
 __ext4_add_entry+0x385/0x3470 fs/ext4/namei.c:2552
 __ext4_link+0x498/0x720 fs/ext4/namei.c:3649
 ext4_link+0x1dc/0x2b0 fs/ext4/namei.c:3689
 vfs_link+0x491/0x650 fs/namei.c:5787
 ovl_do_link fs/overlayfs/overlayfs.h:233 [inline]
 ovl_copy_up_tmpfile fs/overlayfs/copy_up.c:891 [inline]
 ovl_do_copy_up fs/overlayfs/copy_up.c:986 [inline]
 ovl_copy_up_one fs/overlayfs/copy_up.c:1189 [inline]
 ovl_copy_up_flags+0x1c52/0x3930 fs/overlayfs/copy_up.c:1243
 ovl_open+0x13f/0x300 fs/overlayfs/file.c:211
 do_dentry_open+0x816/0x1380 fs/open.c:947
 vfs_open+0x3b/0x340 fs/open.c:1079
 dentry_open+0x61/0xa0 fs/open.c:1102
 ima_calc_file_hash+0x15f/0x890 security/integrity/ima/ima_crypto.c:269
 ima_collect_measurement+0x51b/0xa00 security/integrity/ima/ima_api.c:300
 process_measurement+0x1272/0x1c10 security/integrity/ima/ima_main.c:425
 ima_file_check+0xe1/0x130 security/integrity/ima/ima_main.c:685
 security_file_post_open+0xb3/0x260 security/security.c:2755
 do_open fs/namei.c:4702 [inline]
 path_openat+0x2e90/0x3830 fs/namei.c:4859
 do_file_open+0x23e/0x4a0 fs/namei.c:4888
 do_sys_openat2+0x115/0x200 fs/open.c:1395
 do_sys_open fs/open.c:1401 [inline]
 __do_sys_openat fs/open.c:1417 [inline]
 __se_sys_openat fs/open.c:1412 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1412
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fae54f9ce59
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fae55ddb028 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fae55215fa0 RCX: 00007fae54f9ce59
RDX: 000000000000003f RSI: 0000200000000380 RDI: ffffffffffffff9c
RBP: 00007fae55032e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000186 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fae55216038 R14: 00007fae55215fa0 R15: 00007ffedd6a9a88
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x112785
flags: 0x17ff00000000000(node=0|zone=2|lastcpupid=0x7ff)
page_type: f0(buddy)
raw: 017ff00000000000 ffffea000449e048 ffffea000449e2c8 0000000000000000
raw: 0000000000000000 0000000000000000 00000000f0000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 0, migratetype Unmovable, gfp_mask 0xcc0(GFP_KERNEL), pid 26, tgid 26 (kworker/u9:0), ts 18747225753, free_ts 49527089310
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x22d/0x280 mm/page_alloc.c:1853
 prep_new_page mm/page_alloc.c:1861 [inline]
 get_page_from_freelist+0x24ae/0x2530 mm/page_alloc.c:3941
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5221
 __alloc_pages_noprof+0x10/0x100 mm/page_alloc.c:5255
 alloc_pages_bulk_noprof+0x5ff/0x7c0 mm/page_alloc.c:5175
 ___alloc_pages_bulk mm/kasan/shadow.c:345 [inline]
 __kasan_populate_vmalloc_do mm/kasan/shadow.c:370 [inline]
 __kasan_populate_vmalloc+0xb7/0x1c0 mm/kasan/shadow.c:424
 kasan_populate_vmalloc include/linux/kasan.h:580 [inline]
 alloc_vmap_area+0xd1a/0x1420 mm/vmalloc.c:2123
 __get_vm_area_node+0x1f2/0x300 mm/vmalloc.c:3226
 __vmalloc_node_range_noprof+0x358/0x1730 mm/vmalloc.c:4024
 __vmalloc_node_noprof+0xc2/0x100 mm/vmalloc.c:4124
 alloc_thread_stack_node kernel/fork.c:358 [inline]
 dup_task_struct+0x28e/0x850 kernel/fork.c:928
 copy_process+0x81b/0x42e0 kernel/fork.c:2109
 kernel_clone+0x2d7/0x940 kernel/fork.c:2745
 user_mode_thread+0x110/0x180 kernel/fork.c:2821
 call_usermodehelper_exec_work+0x5c/0x230 kernel/umh.c:171
 process_one_work kernel/workqueue.c:3322 [inline]
 process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405
page last free pid 5625 tgid 5625 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1397 [inline]
 __free_frozen_pages+0xc0d/0xd20 mm/page_alloc.c:2938
 kasan_depopulate_vmalloc_pte+0x6d/0x90 mm/kasan/shadow.c:484
 apply_to_pte_range mm/memory.c:3338 [inline]
 apply_to_pmd_range mm/memory.c:3382 [inline]
 apply_to_pud_range mm/memory.c:3418 [inline]
 apply_to_p4d_range mm/memory.c:3454 [inline]
 __apply_to_page_range+0xbd8/0x1420 mm/memory.c:3490
 __kasan_release_vmalloc+0xa2/0xd0 mm/kasan/shadow.c:602
 kasan_release_vmalloc include/linux/kasan.h:593 [inline]
 kasan_release_vmalloc_node mm/vmalloc.c:2284 [inline]
 purge_vmap_node+0x220/0x960 mm/vmalloc.c:2306
 __purge_vmap_area_lazy+0x783/0xb40 mm/vmalloc.c:2396
 drain_vmap_area_work+0x27/0x40 mm/vmalloc.c:2430
 process_one_work kernel/workqueue.c:3322 [inline]
 process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Memory state around the buggy address:
 ffff888112784f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888112784f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888112785000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                           ^
 ffff888112785080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888112785100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================


***

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2026-04-18  2:04 [moderation/CI] Re: Data in direntry (dirdata) feature syzbot ci
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