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* [syzbot] [gfs2?] KASAN: slab-use-after-free Write in gfs2_qd_dealloc (3)
@ 2025-05-28 10:08 syzbot
  2025-07-23 20:49 ` syzbot
                   ` (2 more replies)
  0 siblings, 3 replies; 9+ messages in thread
From: syzbot @ 2025-05-28 10:08 UTC (permalink / raw)
  To: agruenba, gfs2, linux-kernel, syzkaller-bugs

Hello,

syzbot found the following issue on:

HEAD commit:    01c6df60d5d4 Add linux-next specific files for 20250411
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=13deaa3f980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=db03cefa26ecf825
dashboard link: https://syzkaller.appspot.com/bug?extid=42a37bf8045847d8f9d2
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/928246b3f3d5/disk-01c6df60.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/79a68c4e1134/vmlinux-01c6df60.xz
kernel image: https://storage.googleapis.com/syzbot-assets/9caf8c293819/bzImage-01c6df60.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+42a37bf8045847d8f9d2@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-use-after-free in instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
BUG: KASAN: slab-use-after-free in atomic_dec_and_test include/linux/atomic/atomic-instrumented.h:1383 [inline]
BUG: KASAN: slab-use-after-free in gfs2_qd_dealloc+0x83/0xf0 fs/gfs2/quota.c:112
Write of size 4 at addr ffff888033e98a80 by task kworker/u8:3/53

CPU: 1 UID: 0 PID: 53 Comm: kworker/u8:3 Not tainted 6.15.0-rc1-next-20250411-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Workqueue: bat_events batadv_tt_purge
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:408 [inline]
 print_report+0x16e/0x5b0 mm/kasan/report.c:521
 kasan_report+0x143/0x180 mm/kasan/report.c:634
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x28f/0x2a0 mm/kasan/generic.c:189
 instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
 atomic_dec_and_test include/linux/atomic/atomic-instrumented.h:1383 [inline]
 gfs2_qd_dealloc+0x83/0xf0 fs/gfs2/quota.c:112
 rcu_do_batch kernel/rcu/tree.c:2546 [inline]
 rcu_core+0xaac/0x17a0 kernel/rcu/tree.c:2802
 handle_softirqs+0x2d6/0x9b0 kernel/softirq.c:579
 do_softirq+0x11f/0x1e0 kernel/softirq.c:480
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x1be/0x200 kernel/softirq.c:407
 spin_unlock_bh include/linux/spinlock.h:396 [inline]
 batadv_tt_local_purge+0x2a0/0x340 net/batman-adv/translation-table.c:1315
 batadv_tt_purge+0x35/0xa40 net/batman-adv/translation-table.c:3509
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xac3/0x18e0 kernel/workqueue.c:3319
 worker_thread+0x870/0xd50 kernel/workqueue.c:3400
 kthread+0x7b7/0x940 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 6071:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
 __kasan_kmalloc+0x9d/0xb0 mm/kasan/common.c:394
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __kmalloc_cache_noprof+0x236/0x370 mm/slub.c:4362
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 init_sbd fs/gfs2/ops_fstype.c:77 [inline]
 gfs2_fill_super+0x13e/0x27b0 fs/gfs2/ops_fstype.c:1140
 get_tree_bdev_flags+0x490/0x5c0 fs/super.c:1686
 gfs2_get_tree+0x54/0x220 fs/gfs2/ops_fstype.c:1330
 vfs_get_tree+0x90/0x2b0 fs/super.c:1809
 do_new_mount+0x2cf/0xb70 fs/namespace.c:3879
 do_mount fs/namespace.c:4219 [inline]
 __do_sys_mount fs/namespace.c:4430 [inline]
 __se_sys_mount+0x38c/0x400 fs/namespace.c:4407
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 6071:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x59/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2389 [inline]
 slab_free mm/slub.c:4646 [inline]
 kfree+0x198/0x430 mm/slub.c:4845
 free_sbd fs/gfs2/ops_fstype.c:69 [inline]
 gfs2_fill_super+0x14bf/0x27b0 fs/gfs2/ops_fstype.c:1313
 get_tree_bdev_flags+0x490/0x5c0 fs/super.c:1686
 gfs2_get_tree+0x54/0x220 fs/gfs2/ops_fstype.c:1330
 vfs_get_tree+0x90/0x2b0 fs/super.c:1809
 do_new_mount+0x2cf/0xb70 fs/namespace.c:3879
 do_mount fs/namespace.c:4219 [inline]
 __do_sys_mount fs/namespace.c:4430 [inline]
 __se_sys_mount+0x38c/0x400 fs/namespace.c:4407
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888033e98000
 which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 2688 bytes inside of
 freed 8192-byte region [ffff888033e98000, ffff888033e9a000)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x33e98
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88801b042280 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000020002 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88801b042280 dead000000000100 dead000000000122
head: 0000000000000000 0000000000020002 00000000f5000000 0000000000000000
head: 00fff00000000003 ffffea0000cfa601 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 5487, tgid 5487 (run-parts), ts 55699630622, free_ts 55641758587
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1f4/0x240 mm/page_alloc.c:1718
 prep_new_page mm/page_alloc.c:1726 [inline]
 get_page_from_freelist+0x360a/0x37a0 mm/page_alloc.c:3700
 __alloc_frozen_pages_noprof+0x211/0x5b0 mm/page_alloc.c:4982
 alloc_pages_mpol+0x339/0x690 mm/mempolicy.c:2301
 alloc_slab_page mm/slub.c:2459 [inline]
 allocate_slab+0x8f/0x3a0 mm/slub.c:2623
 new_slab mm/slub.c:2676 [inline]
 ___slab_alloc+0xc3b/0x1500 mm/slub.c:3862
 __slab_alloc+0x58/0xa0 mm/slub.c:3952
 __slab_alloc_node mm/slub.c:4027 [inline]
 slab_alloc_node mm/slub.c:4188 [inline]
 __kmalloc_cache_noprof+0x26a/0x370 mm/slub.c:4357
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 tomoyo_print_bprm security/tomoyo/audit.c:26 [inline]
 tomoyo_init_log+0x121e/0x2150 security/tomoyo/audit.c:264
 tomoyo_supervisor+0x3c0/0x18b0 security/tomoyo/common.c:2198
 tomoyo_audit_env_log security/tomoyo/environ.c:36 [inline]
 tomoyo_env_perm+0x17b/0x220 security/tomoyo/environ.c:63
 tomoyo_environ security/tomoyo/domain.c:672 [inline]
 tomoyo_find_next_domain+0x1497/0x1dd0 security/tomoyo/domain.c:888
 tomoyo_bprm_check_security+0x11a/0x180 security/tomoyo/tomoyo.c:102
 security_bprm_check+0x86/0x250 security/security.c:1302
 search_binary_handler fs/exec.c:1768 [inline]
 exec_binprm fs/exec.c:1810 [inline]
 bprm_execve+0x903/0x1430 fs/exec.c:1862
 do_execveat_common+0x57c/0x710 fs/exec.c:1968
page last free pid 5485 tgid 5485 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1262 [inline]
 __free_frozen_pages+0xde8/0x10a0 mm/page_alloc.c:2725
 __slab_free+0x2c6/0x390 mm/slub.c:4557
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x23/0x80 mm/kasan/common.c:329
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4151 [inline]
 slab_alloc_node mm/slub.c:4200 [inline]
 __do_kmalloc_node mm/slub.c:4330 [inline]
 __kmalloc_noprof+0x238/0x4d0 mm/slub.c:4343
 kmalloc_noprof include/linux/slab.h:909 [inline]
 tomoyo_add_entry security/tomoyo/common.c:2132 [inline]
 tomoyo_supervisor+0xc94/0x18b0 security/tomoyo/common.c:2204
 tomoyo_audit_path_log security/tomoyo/file.c:168 [inline]
 tomoyo_path_permission+0x243/0x360 security/tomoyo/file.c:587
 tomoyo_check_open_permission+0x309/0x4f0 security/tomoyo/file.c:777
 security_file_open+0xac/0x250 security/security.c:3114
 do_dentry_open+0x320/0x1960 fs/open.c:933
 vfs_open+0x3b/0x370 fs/open.c:1086
 do_open fs/namei.c:3849 [inline]
 path_openat+0x2caf/0x35d0 fs/namei.c:4008
 do_filp_open+0x284/0x4e0 fs/namei.c:4035
 do_sys_openat2+0x12b/0x1d0 fs/open.c:1429
 do_sys_open fs/open.c:1444 [inline]
 __do_sys_openat fs/open.c:1460 [inline]
 __se_sys_openat fs/open.c:1455 [inline]
 __x64_sys_openat+0x249/0x2a0 fs/open.c:1455

Memory state around the buggy address:
 ffff888033e98980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888033e98a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888033e98a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff888033e98b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888033e98b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


---
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^ permalink raw reply	[flat|nested] 9+ messages in thread
[parent not found: <177754835224.2147696.8354228851433174481@gmail.com>]
[parent not found: <177758824329.163667.6298575861470288172@gmail.com>]
end of thread, other threads:[~2026-04-30 23:05 UTC | newest]

Thread overview: 9+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2025-05-28 10:08 [syzbot] [gfs2?] KASAN: slab-use-after-free Write in gfs2_qd_dealloc (3) syzbot
2025-07-23 20:49 ` syzbot
2025-07-24 11:38   ` Andrew Price
2025-07-24 11:57     ` syzbot
2025-07-24 12:11       ` Andrew Price
2026-04-30 11:25 ` Forwarded: " syzbot
2026-04-30 22:30 ` syzbot
     [not found] <177754835224.2147696.8354228851433174481@gmail.com>
2026-04-30 12:51 ` syzbot
     [not found] <177758824329.163667.6298575861470288172@gmail.com>
2026-04-30 23:05 ` syzbot

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