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* [moderation/CI] Re: Implement a new generic pagewalk API
@ 2026-04-12 22:28 syzbot ci
  2026-04-13  7:35 ` Aleksandr Nogikh
  0 siblings, 1 reply; 6+ messages in thread
From: syzbot ci @ 2026-04-12 22:28 UTC (permalink / raw)
  To: syzkaller-upstream-moderation; +Cc: syzbot

syzbot ci has tested the following series

[v1] Implement a new generic pagewalk API
https://lore.kernel.org/all/20260412174244.133715-1-osalvador@suse.de
* [RFC PATCH 1/7] mm: Add softleaf_from_pud
* [RFC PATCH 2/7] mm: Add {pmd,pud}_huge_lock helper
* [RFC PATCH 3/7] mm: Implement folio_pmd_batch
* [RFC PATCH 4/7] mm: Implement pt_range_walk
* [RFC PATCH 5/7] mm: Make /proc/pid/smaps use the new generic pagewalk API
* [RFC PATCH 6/7] mm: Make /proc/pid/numa_maps use the new generic pagewalk API
* [RFC PATCH 7/7] mm: Make /proc/pid/pagemap use the new generic pagewalk API

and found the following issues:
* KASAN: slab-out-of-bounds Write in pagemap_read
* WARNING in pt_range_walk

Full report is available here:
https://ci.syzbot.org/series/1f85248a-1ac0-48e8-8ce3-edb89a6b9ee5

***

KASAN: slab-out-of-bounds Write in pagemap_read

tree:      torvalds
URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux
base:      857fa8f2a5b184c206c703a3d9ce05cea683cfed
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/932ed80d-9fb1-4c99-8096-4b7a9324bb7c/config
syz repro: https://ci.syzbot.org/findings/1083a63d-0470-4ce7-8943-0a60046b9269/syz_repro

==================================================================
BUG: KASAN: slab-out-of-bounds in add_to_pagemap fs/proc/task_mmu.c:1740 [inline]
BUG: KASAN: slab-out-of-bounds in pagemap_read_walk_range fs/proc/task_mmu.c:2736 [inline]
BUG: KASAN: slab-out-of-bounds in pagemap_read+0x19bc/0x21a0 fs/proc/task_mmu.c:2829
Write of size 8 at addr ffff88816d32b000 by task syz.0.17/5958

CPU: 0 UID: 0 PID: 5958 Comm: syz.0.17 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
 add_to_pagemap fs/proc/task_mmu.c:1740 [inline]
 pagemap_read_walk_range fs/proc/task_mmu.c:2736 [inline]
 pagemap_read+0x19bc/0x21a0 fs/proc/task_mmu.c:2829
 vfs_read+0x20c/0xa70 fs/read_write.c:572
 ksys_pread64 fs/read_write.c:765 [inline]
 __do_sys_pread64 fs/read_write.c:773 [inline]
 __se_sys_pread64 fs/read_write.c:770 [inline]
 __x64_sys_pread64+0x199/0x230 fs/read_write.c:770
 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: 0033:0x7fd47239c819
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:00007fd473284028 EFLAGS: 00000246 ORIG_RAX: 0000000000000011
RAX: ffffffffffffffda RBX: 00007fd472615fa0 RCX: 00007fd47239c819
RDX: 0000000000019000 RSI: 0000200000000200 RDI: 0000000000000003
RBP: 00007fd472432c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000001000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd472616038 R14: 00007fd472615fa0 R15: 00007ffe3c81aa88
 </TASK>

Allocated by task 5958:
 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:5339
 kmalloc_noprof include/linux/slab.h:962 [inline]
 kmalloc_array_noprof include/linux/slab.h:1109 [inline]
 pagemap_read+0x287/0x21a0 fs/proc/task_mmu.c:2781
 vfs_read+0x20c/0xa70 fs/read_write.c:572
 ksys_pread64 fs/read_write.c:765 [inline]
 __do_sys_pread64 fs/read_write.c:773 [inline]
 __se_sys_pread64 fs/read_write.c:770 [inline]
 __x64_sys_pread64+0x199/0x230 fs/read_write.c:770
 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 ffff88816d32a000
 which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 0 bytes to the right of
 allocated 4096-byte region [ffff88816d32a000, ffff88816d32b000)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x16d328
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 ffff888100042140 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000040004 00000000f5000000 0000000000000000
head: 057ff00000000040 ffff888100042140 dead000000000100 dead000000000122
head: 0000000000000000 0000000000040004 00000000f5000000 0000000000000000
head: 057ff00000000003 ffffea0005b4ca01 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 1, tgid 1 (swapper/0), ts 20801987900, free_ts 13278585415
 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:3255 [inline]
 allocate_slab+0x77/0x660 mm/slub.c:3444
 new_slab mm/slub.c:3502 [inline]
 refill_objects+0x331/0x3c0 mm/slub.c:7134
 refill_sheaf mm/slub.c:2804 [inline]
 __pcs_replace_empty_main+0x2b9/0x620 mm/slub.c:4578
 alloc_from_pcs mm/slub.c:4681 [inline]
 slab_alloc_node mm/slub.c:4815 [inline]
 __kmalloc_cache_noprof+0x392/0x660 mm/slub.c:5334
 kmalloc_noprof include/linux/slab.h:962 [inline]
 kzalloc_noprof include/linux/slab.h:1200 [inline]
 kobject_uevent_env+0x28c/0x9e0 lib/kobject_uevent.c:540
 driver_register+0x2d4/0x320 drivers/base/driver.c:257
 usb_register_driver+0x1e4/0x390 drivers/usb/core/driver.c:1078
 hid_init+0x39/0x70 drivers/hid/usbhid/hid-core.c:1710
 do_one_initcall+0x250/0x8d0 init/main.c:1382
 do_initcall_level+0x104/0x190 init/main.c:1444
 do_initcalls+0x59/0xa0 init/main.c:1460
 kernel_init_freeable+0x2a6/0x3e0 init/main.c:1692
 kernel_init+0x1d/0x1d0 init/main.c:1582
page last free pid 10 tgid 10 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:3275 [inline]
 process_scheduled_works+0xb02/0x1830 kernel/workqueue.c:3358
 worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439
 kthread+0x388/0x470 kernel/kthread.c:467
 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:
 ffff88816d32af00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88816d32af80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88816d32b000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                   ^
 ffff88816d32b080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88816d32b100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


***

WARNING in pt_range_walk

tree:      torvalds
URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux
base:      857fa8f2a5b184c206c703a3d9ce05cea683cfed
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/932ed80d-9fb1-4c99-8096-4b7a9324bb7c/config
syz repro: https://ci.syzbot.org/findings/e7c203a3-133f-4435-b9ed-ee292b6685fe/syz_repro

------------[ cut here ]------------
next_addr < vma->vm_start || next_addr >= vma->vm_end
WARNING: mm/pagewalk.c:1052 at pt_range_walk+0x145/0x35f0 mm/pagewalk.c:1052, CPU#1: syz.1.18/6005
Modules linked in:
CPU: 1 UID: 0 PID: 6005 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
RIP: 0010:pt_range_walk+0x145/0x35f0 mm/pagewalk.c:1052
Code: df e8 9f 1a 15 00 49 89 dc 48 8b 1b 4c 89 ff 48 89 de e8 7e a5 aa ff 49 39 df 4c 89 b4 24 38 01 00 00 73 14 e8 0c a3 aa ff 90 <0f> 0b 90 41 be 01 00 00 00 e9 e5 21 00 00 49 8d 5c 24 08 48 89 d8
RSP: 0018:ffffc90003a279a0 EFLAGS: 00010293
RAX: ffffffff821b140c RBX: 0000200001000000 RCX: ffff8881027a5700
RDX: 0000000000000000 RSI: 0000200001000000 RDI: 0000200001000000
RBP: ffffc90003a27bb0 R08: 00000000000000ff R09: 0000000000000003
R10: 0000000000000002 R11: 0000000000000000 R12: ffff888105317380
R13: dffffc0000000000 R14: 1ffff92000744f60 R15: 0000200001000000
FS:  00007f0ccbd736c0(0000) GS:ffff8882a9467000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f0ccb04edd5 CR3: 0000000115dba000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 pagemap_scan_walk fs/proc/task_mmu.c:2479 [inline]
 do_pagemap_scan fs/proc/task_mmu.c:2573 [inline]
 do_pagemap_cmd+0xfd5/0x2600 fs/proc/task_mmu.c:2869
 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+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0ccaf9c819
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:00007f0ccbd73028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f0ccb215fa0 RCX: 00007f0ccaf9c819
RDX: 0000200000000100 RSI: 00000000c0606610 RDI: 0000000000000003
RBP: 00007f0ccb032c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0ccb216038 R14: 00007f0ccb215fa0 R15: 00007ffd9c7ebb48
 </TASK>


***

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:
[akpm@linux-foundation.org david@kernel.org david@redhat.com linux-kernel@vger.kernel.org linux-mm@kvack.org lorenzo.stoakes@oracle.com mhocko@suse.com muchun.song@linux.dev osalvador@suse.de vbabka@kernel.org]

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

* Re: [moderation/CI] Re: Implement a new generic pagewalk API
  2026-04-12 22:28 syzbot ci
@ 2026-04-13  7:35 ` Aleksandr Nogikh
  0 siblings, 0 replies; 6+ messages in thread
From: Aleksandr Nogikh @ 2026-04-13  7:35 UTC (permalink / raw)
  To: syzbot ci; +Cc: syzkaller-upstream-moderation, syzbot

#syz upstream

On Mon, Apr 13, 2026 at 12:28 AM syzbot ci
<syzbot+cif2f54dd12749875d@syzkaller.appspotmail.com> wrote:
>
> syzbot ci has tested the following series
>
> [v1] Implement a new generic pagewalk API
> https://lore.kernel.org/all/20260412174244.133715-1-osalvador@suse.de
> * [RFC PATCH 1/7] mm: Add softleaf_from_pud
> * [RFC PATCH 2/7] mm: Add {pmd,pud}_huge_lock helper
> * [RFC PATCH 3/7] mm: Implement folio_pmd_batch
> * [RFC PATCH 4/7] mm: Implement pt_range_walk
> * [RFC PATCH 5/7] mm: Make /proc/pid/smaps use the new generic pagewalk API
> * [RFC PATCH 6/7] mm: Make /proc/pid/numa_maps use the new generic pagewalk API
> * [RFC PATCH 7/7] mm: Make /proc/pid/pagemap use the new generic pagewalk API
>
> and found the following issues:
> * KASAN: slab-out-of-bounds Write in pagemap_read
> * WARNING in pt_range_walk
>
> Full report is available here:
> https://ci.syzbot.org/series/1f85248a-1ac0-48e8-8ce3-edb89a6b9ee5
>
> ***
>
> KASAN: slab-out-of-bounds Write in pagemap_read
>
> tree:      torvalds
> URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux
> base:      857fa8f2a5b184c206c703a3d9ce05cea683cfed
> 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/932ed80d-9fb1-4c99-8096-4b7a9324bb7c/config
> syz repro: https://ci.syzbot.org/findings/1083a63d-0470-4ce7-8943-0a60046b9269/syz_repro
>
> ==================================================================
> BUG: KASAN: slab-out-of-bounds in add_to_pagemap fs/proc/task_mmu.c:1740 [inline]
> BUG: KASAN: slab-out-of-bounds in pagemap_read_walk_range fs/proc/task_mmu.c:2736 [inline]
> BUG: KASAN: slab-out-of-bounds in pagemap_read+0x19bc/0x21a0 fs/proc/task_mmu.c:2829
> Write of size 8 at addr ffff88816d32b000 by task syz.0.17/5958
>
> CPU: 0 UID: 0 PID: 5958 Comm: syz.0.17 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
>  add_to_pagemap fs/proc/task_mmu.c:1740 [inline]
>  pagemap_read_walk_range fs/proc/task_mmu.c:2736 [inline]
>  pagemap_read+0x19bc/0x21a0 fs/proc/task_mmu.c:2829
>  vfs_read+0x20c/0xa70 fs/read_write.c:572
>  ksys_pread64 fs/read_write.c:765 [inline]
>  __do_sys_pread64 fs/read_write.c:773 [inline]
>  __se_sys_pread64 fs/read_write.c:770 [inline]
>  __x64_sys_pread64+0x199/0x230 fs/read_write.c:770
>  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: 0033:0x7fd47239c819
> 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:00007fd473284028 EFLAGS: 00000246 ORIG_RAX: 0000000000000011
> RAX: ffffffffffffffda RBX: 00007fd472615fa0 RCX: 00007fd47239c819
> RDX: 0000000000019000 RSI: 0000200000000200 RDI: 0000000000000003
> RBP: 00007fd472432c91 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000001000000000 R11: 0000000000000246 R12: 0000000000000000
> R13: 00007fd472616038 R14: 00007fd472615fa0 R15: 00007ffe3c81aa88
>  </TASK>
>
> Allocated by task 5958:
>  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:5339
>  kmalloc_noprof include/linux/slab.h:962 [inline]
>  kmalloc_array_noprof include/linux/slab.h:1109 [inline]
>  pagemap_read+0x287/0x21a0 fs/proc/task_mmu.c:2781
>  vfs_read+0x20c/0xa70 fs/read_write.c:572
>  ksys_pread64 fs/read_write.c:765 [inline]
>  __do_sys_pread64 fs/read_write.c:773 [inline]
>  __se_sys_pread64 fs/read_write.c:770 [inline]
>  __x64_sys_pread64+0x199/0x230 fs/read_write.c:770
>  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 ffff88816d32a000
>  which belongs to the cache kmalloc-4k of size 4096
> The buggy address is located 0 bytes to the right of
>  allocated 4096-byte region [ffff88816d32a000, ffff88816d32b000)
>
> The buggy address belongs to the physical page:
> page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x16d328
> 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 ffff888100042140 dead000000000100 dead000000000122
> raw: 0000000000000000 0000000000040004 00000000f5000000 0000000000000000
> head: 057ff00000000040 ffff888100042140 dead000000000100 dead000000000122
> head: 0000000000000000 0000000000040004 00000000f5000000 0000000000000000
> head: 057ff00000000003 ffffea0005b4ca01 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 1, tgid 1 (swapper/0), ts 20801987900, free_ts 13278585415
>  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:3255 [inline]
>  allocate_slab+0x77/0x660 mm/slub.c:3444
>  new_slab mm/slub.c:3502 [inline]
>  refill_objects+0x331/0x3c0 mm/slub.c:7134
>  refill_sheaf mm/slub.c:2804 [inline]
>  __pcs_replace_empty_main+0x2b9/0x620 mm/slub.c:4578
>  alloc_from_pcs mm/slub.c:4681 [inline]
>  slab_alloc_node mm/slub.c:4815 [inline]
>  __kmalloc_cache_noprof+0x392/0x660 mm/slub.c:5334
>  kmalloc_noprof include/linux/slab.h:962 [inline]
>  kzalloc_noprof include/linux/slab.h:1200 [inline]
>  kobject_uevent_env+0x28c/0x9e0 lib/kobject_uevent.c:540
>  driver_register+0x2d4/0x320 drivers/base/driver.c:257
>  usb_register_driver+0x1e4/0x390 drivers/usb/core/driver.c:1078
>  hid_init+0x39/0x70 drivers/hid/usbhid/hid-core.c:1710
>  do_one_initcall+0x250/0x8d0 init/main.c:1382
>  do_initcall_level+0x104/0x190 init/main.c:1444
>  do_initcalls+0x59/0xa0 init/main.c:1460
>  kernel_init_freeable+0x2a6/0x3e0 init/main.c:1692
>  kernel_init+0x1d/0x1d0 init/main.c:1582
> page last free pid 10 tgid 10 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:3275 [inline]
>  process_scheduled_works+0xb02/0x1830 kernel/workqueue.c:3358
>  worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439
>  kthread+0x388/0x470 kernel/kthread.c:467
>  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:
>  ffff88816d32af00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>  ffff88816d32af80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> >ffff88816d32b000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>                    ^
>  ffff88816d32b080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>  ffff88816d32b100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> ==================================================================
>
>
> ***
>
> WARNING in pt_range_walk
>
> tree:      torvalds
> URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux
> base:      857fa8f2a5b184c206c703a3d9ce05cea683cfed
> 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/932ed80d-9fb1-4c99-8096-4b7a9324bb7c/config
> syz repro: https://ci.syzbot.org/findings/e7c203a3-133f-4435-b9ed-ee292b6685fe/syz_repro
>
> ------------[ cut here ]------------
> next_addr < vma->vm_start || next_addr >= vma->vm_end
> WARNING: mm/pagewalk.c:1052 at pt_range_walk+0x145/0x35f0 mm/pagewalk.c:1052, CPU#1: syz.1.18/6005
> Modules linked in:
> CPU: 1 UID: 0 PID: 6005 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
> RIP: 0010:pt_range_walk+0x145/0x35f0 mm/pagewalk.c:1052
> Code: df e8 9f 1a 15 00 49 89 dc 48 8b 1b 4c 89 ff 48 89 de e8 7e a5 aa ff 49 39 df 4c 89 b4 24 38 01 00 00 73 14 e8 0c a3 aa ff 90 <0f> 0b 90 41 be 01 00 00 00 e9 e5 21 00 00 49 8d 5c 24 08 48 89 d8
> RSP: 0018:ffffc90003a279a0 EFLAGS: 00010293
> RAX: ffffffff821b140c RBX: 0000200001000000 RCX: ffff8881027a5700
> RDX: 0000000000000000 RSI: 0000200001000000 RDI: 0000200001000000
> RBP: ffffc90003a27bb0 R08: 00000000000000ff R09: 0000000000000003
> R10: 0000000000000002 R11: 0000000000000000 R12: ffff888105317380
> R13: dffffc0000000000 R14: 1ffff92000744f60 R15: 0000200001000000
> FS:  00007f0ccbd736c0(0000) GS:ffff8882a9467000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007f0ccb04edd5 CR3: 0000000115dba000 CR4: 00000000000006f0
> Call Trace:
>  <TASK>
>  pagemap_scan_walk fs/proc/task_mmu.c:2479 [inline]
>  do_pagemap_scan fs/proc/task_mmu.c:2573 [inline]
>  do_pagemap_cmd+0xfd5/0x2600 fs/proc/task_mmu.c:2869
>  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+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
>  entry_SYSCALL_64_after_hwframe+0x77/0x7f
> RIP: 0033:0x7f0ccaf9c819
> 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:00007f0ccbd73028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
> RAX: ffffffffffffffda RBX: 00007f0ccb215fa0 RCX: 00007f0ccaf9c819
> RDX: 0000200000000100 RSI: 00000000c0606610 RDI: 0000000000000003
> RBP: 00007f0ccb032c91 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> R13: 00007f0ccb216038 R14: 00007f0ccb215fa0 R15: 00007ffd9c7ebb48
>  </TASK>
>
>
> ***
>
> 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:
> [akpm@linux-foundation.org david@kernel.org david@redhat.com linux-kernel@vger.kernel.org linux-mm@kvack.org lorenzo.stoakes@oracle.com mhocko@suse.com muchun.song@linux.dev osalvador@suse.de vbabka@kernel.org]
>
> If the report looks fine to you, reply with:
> #syz upstream
>
> If the report is a false positive, reply with
> #syz invalid
>
> --
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^ permalink raw reply	[flat|nested] 6+ messages in thread

* [moderation/CI] Re: Implement a new generic pagewalk API
@ 2026-04-26 17:13 syzbot ci
  2026-04-26 19:00 ` Aleksandr Nogikh
  0 siblings, 1 reply; 6+ messages in thread
From: syzbot ci @ 2026-04-26 17:13 UTC (permalink / raw)
  To: syzkaller-upstream-moderation; +Cc: syzbot

syzbot ci has tested the following series

[v2] Implement a new generic pagewalk API
https://lore.kernel.org/all/20260426125719.24698-1-osalvador@suse.de
* [RFC PATCH v2 1/7] mm: Add softleaf_from_pud
* [RFC PATCH v2 2/7] mm: Add {pmd,pud}_huge_lock helper
* [RFC PATCH v2 3/7] mm: Implement folio_pmd_batch
* [RFC PATCH v2 4/7] mm: Implement pt_range_walk
* [RFC PATCH v2 5/7] mm: Make /proc/pid/smaps use the new generic pagewalk API
* [RFC PATCH v2 6/7] mm: Make /proc/pid/numa_maps use the new generic pagewalk API
* [RFC PATCH v2 7/7] mm: Make /proc/pid/pagemap use the new generic pagewalk API

and found the following issues:
* KASAN: slab-out-of-bounds Write in pagemap_read
* WARNING in __page_table_check_pmds_set
* WARNING in pt_range_walk
* WARNING: bad unlock balance in pt_range_walk

Full report is available here:
https://ci.syzbot.org/series/409219de-ca42-45a5-9204-0b315095160c

***

KASAN: slab-out-of-bounds Write in pagemap_read

tree:      mm-new
URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/akpm/mm.git
base:      819bd270abf9de3b7f306e233054b85a07c47820
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/0361816f-57b2-43e4-aef2-186d8d35fdc9/config
syz repro: https://ci.syzbot.org/findings/7f740037-7398-46f2-aa01-a57caa186d06/syz_repro

==================================================================
BUG: KASAN: slab-out-of-bounds in add_to_pagemap fs/proc/task_mmu.c:1776 [inline]
BUG: KASAN: slab-out-of-bounds in pagemap_read_walk_range fs/proc/task_mmu.c:2949 [inline]
BUG: KASAN: slab-out-of-bounds in pagemap_read+0x1d60/0x2810 fs/proc/task_mmu.c:3092
Write of size 8 at addr ffff88816f1bd000 by task syz.1.18/5957

CPU: 1 UID: 0 PID: 5957 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 mm/kasan/report.c:378 [inline]
 print_report+0xba/0x230 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 add_to_pagemap fs/proc/task_mmu.c:1776 [inline]
 pagemap_read_walk_range fs/proc/task_mmu.c:2949 [inline]
 pagemap_read+0x1d60/0x2810 fs/proc/task_mmu.c:3092
 vfs_read+0x20c/0xa70 fs/read_write.c:572
 ksys_pread64 fs/read_write.c:765 [inline]
 __do_sys_pread64 fs/read_write.c:773 [inline]
 __se_sys_pread64 fs/read_write.c:770 [inline]
 __x64_sys_pread64+0x199/0x230 fs/read_write.c:770
 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: 0033:0x7f340679cdd9
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:00007f34075d2028 EFLAGS: 00000246 ORIG_RAX: 0000000000000011
RAX: ffffffffffffffda RBX: 00007f3406a15fa0 RCX: 00007f340679cdd9
RDX: 0000000000019020 RSI: 0000200000000200 RDI: 0000000000000003
RBP: 00007f3406832d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000001000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3406a16038 R14: 00007f3406a15fa0 R15: 00007ffdb721f7e8
 </TASK>

Allocated by task 5957:
 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:5339
 kmalloc_noprof include/linux/slab.h:962 [inline]
 kmalloc_array_noprof include/linux/slab.h:1109 [inline]
 pagemap_read+0x27d/0x2810 fs/proc/task_mmu.c:3033
 vfs_read+0x20c/0xa70 fs/read_write.c:572
 ksys_pread64 fs/read_write.c:765 [inline]
 __do_sys_pread64 fs/read_write.c:773 [inline]
 __se_sys_pread64 fs/read_write.c:770 [inline]
 __x64_sys_pread64+0x199/0x230 fs/read_write.c:770
 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 ffff88816f1bc000
 which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 0 bytes to the right of
 allocated 4096-byte region [ffff88816f1bc000, ffff88816f1bd000)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88816f1b8000 pfn:0x16f1b8
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x57ff00000000240(workingset|head|node=1|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 057ff00000000240 ffff888100042140 ffff888160400a08 ffffea0005c6fe10
raw: ffff88816f1b8000 0000000000040003 00000000f5000000 0000000000000000
head: 057ff00000000240 ffff888100042140 ffff888160400a08 ffffea0005c6fe10
head: ffff88816f1b8000 0000000000040003 00000000f5000000 0000000000000000
head: 057ff00000000003 ffffea0005bc6e01 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 5715, tgid 5715 (rm), ts 50636400155, free_ts 46909302793
 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:3255 [inline]
 allocate_slab+0x77/0x660 mm/slub.c:3444
 new_slab mm/slub.c:3502 [inline]
 refill_objects+0x331/0x3c0 mm/slub.c:7134
 refill_sheaf mm/slub.c:2804 [inline]
 __pcs_replace_empty_main+0x2b9/0x620 mm/slub.c:4578
 alloc_from_pcs mm/slub.c:4681 [inline]
 slab_alloc_node mm/slub.c:4815 [inline]
 __do_kmalloc_node mm/slub.c:5218 [inline]
 __kmalloc_noprof+0x474/0x760 mm/slub.c:5231
 kmalloc_noprof include/linux/slab.h:966 [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_unlink+0xaa/0xf0 security/tomoyo/tomoyo.c:162
 security_path_unlink+0x15f/0x330 security/security.c:1457
 filename_unlinkat+0x349/0x610 fs/namei.c:5537
 __do_sys_unlink fs/namei.c:5575 [inline]
 __se_sys_unlink+0x2e/0x140 fs/namei.c:5572
 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 5257 tgid 5257 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:5532
 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:4501 [inline]
 slab_alloc_node mm/slub.c:4830 [inline]
 kmem_cache_alloc_noprof+0x2bc/0x650 mm/slub.c:4837
 alloc_filename fs/namei.c:142 [inline]
 do_getname+0x2e/0x250 fs/namei.c:182
 getname_flags fs/namei.c:225 [inline]
 getname include/linux/fs.h:2512 [inline]
 class_filename_constructor include/linux/fs.h:2539 [inline]
 __do_sys_unlink fs/namei.c:5574 [inline]
 __se_sys_unlink+0x1e/0x140 fs/namei.c:5572
 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:
 ffff88816f1bcf00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88816f1bcf80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88816f1bd000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                   ^
 ffff88816f1bd080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88816f1bd100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


***

WARNING in __page_table_check_pmds_set

tree:      mm-new
URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/akpm/mm.git
base:      819bd270abf9de3b7f306e233054b85a07c47820
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/0361816f-57b2-43e4-aef2-186d8d35fdc9/config
syz repro: https://ci.syzbot.org/findings/f8fe52b4-cef7-4d25-8e60-cbbb1a4f4df5/syz_repro

------------[ cut here ]------------
softleaf_cached_writable(entry)
WARNING: mm/page_table_check.c:227 at page_table_check_pmd_flags mm/page_table_check.c:227 [inline], CPU#1: syz.0.17/6022
WARNING: mm/page_table_check.c:227 at __page_table_check_pmds_set+0x18e/0x340 mm/page_table_check.c:240, CPU#1: syz.0.17/6022
Modules linked in:
CPU: 1 UID: 0 PID: 6022 Comm: syz.0.17 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
RIP: 0010:page_table_check_pmd_flags mm/page_table_check.c:227 [inline]
RIP: 0010:__page_table_check_pmds_set+0x18e/0x340 mm/page_table_check.c:240
Code: 89 fe e8 85 44 89 ff 48 b8 00 00 00 00 00 00 00 94 4c 01 f8 48 c1 e8 3b 0f 94 c0 4d 39 e5 76 0f 84 c0 74 0b e8 83 3f 89 ff 90 <0f> 0b 90 eb 05 e8 78 3f 89 ff 31 ff 89 ee e8 af 43 89 ff 41 89 ef
RSP: 0018:ffffc90003ce7af8 EFLAGS: 00010293
RAX: ffffffff823c4d7d RBX: ffff888111416001 RCX: ffff88816cbd1d00
RDX: 0000000000000000 RSI: 6c00000000000000 RDI: 6c00000000000000
RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000003
R10: 0000000000000002 R11: 0000000000000000 R12: c7fffffffffffffe
R13: dfffffffdc9bfe06 R14: ffff888111416008 R15: 6c00000000000000
FS:  00007ff0386af6c0(0000) GS:ffff8882a9466000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555574a1a9e8 CR3: 00000001063c6000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 page_table_check_pmds_set include/linux/page_table_check.h:92 [inline]
 set_pmd_at arch/x86/include/asm/pgtable.h:1234 [inline]
 make_uffd_wp_pmd fs/proc/task_mmu.c:1903 [inline]
 pagemap_scan_walk fs/proc/task_mmu.c:2631 [inline]
 do_pagemap_scan fs/proc/task_mmu.c:2785 [inline]
 do_pagemap_cmd+0x3bd8/0x4310 fs/proc/task_mmu.c:3131
 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+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff03779cdd9
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:00007ff0386af028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007ff037a16090 RCX: 00007ff03779cdd9
RDX: 00002000000001c0 RSI: 00000000c0606610 RDI: 0000000000000003
RBP: 00007ff037832d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff037a16128 R14: 00007ff037a16090 R15: 00007ffd47ec5488
 </TASK>


***

WARNING in pt_range_walk

tree:      mm-new
URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/akpm/mm.git
base:      819bd270abf9de3b7f306e233054b85a07c47820
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/0361816f-57b2-43e4-aef2-186d8d35fdc9/config
syz repro: https://ci.syzbot.org/findings/02bfe437-a81f-4510-9fff-4b769eb9a0a4/syz_repro

------------[ cut here ]------------
next_addr < vma->vm_start || next_addr >= vma->vm_end
WARNING: mm/pagewalk.c:1052 at pt_range_walk+0x14e/0x35a0 mm/pagewalk.c:1052, CPU#1: syz.2.19/6013
Modules linked in:
CPU: 1 UID: 0 PID: 6013 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
RIP: 0010:pt_range_walk+0x14e/0x35a0 mm/pagewalk.c:1052
Code: 74 08 48 89 df e8 12 1a 15 00 49 89 de 48 8b 1b 48 8b 7c 24 10 48 89 de e8 6f a5 aa ff 48 39 5c 24 10 73 13 e8 03 a3 aa ff 90 <0f> 0b 90 b8 01 00 00 00 e9 88 2b 00 00 49 8d 5e 08 48 89 d8 48 c1
RSP: 0018:ffffc90003d37920 EFLAGS: 00010293
RAX: ffffffff821b11f0 RBX: 0000200000800000 RCX: ffff8881134f5700
RDX: 0000000000000000 RSI: 0000200000800000 RDI: 0000200000800000
RBP: ffffc90003d37b30 R08: 00000000000000ff R09: 1ffff1102dc8b830
R10: dffffc0000000000 R11: ffffed102dc8b831 R12: ffff8881709b1800
R13: dffffc0000000000 R14: ffff8881709b1800 R15: 0000200000800000
FS:  00007f33141ff6c0(0000) GS:ffff8882a9466000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f331344f0d1 CR3: 000000017150e000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 pagemap_scan_walk fs/proc/task_mmu.c:2463 [inline]
 do_pagemap_scan fs/proc/task_mmu.c:2785 [inline]
 do_pagemap_cmd+0x3924/0x4310 fs/proc/task_mmu.c:3131
 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+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f331339cdd9
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:00007f33141ff028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f3313615fa0 RCX: 00007f331339cdd9
RDX: 0000200000000140 RSI: 00000000c0606610 RDI: 0000000000000003
RBP: 00007f3313432d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3313616038 R14: 00007f3313615fa0 R15: 00007fff980e14d8
 </TASK>


***

WARNING: bad unlock balance in pt_range_walk

tree:      mm-new
URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/akpm/mm.git
base:      819bd270abf9de3b7f306e233054b85a07c47820
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/0361816f-57b2-43e4-aef2-186d8d35fdc9/config
syz repro: https://ci.syzbot.org/findings/1e53935d-6673-468b-905d-88da8f1e39f3/syz_repro

loop1: detected capacity change from 0 to 4096
=====================================
WARNING: bad unlock balance detected!
syzkaller #0 Not tainted
-------------------------------------
syz.1.18/5968 is trying to release lock (ptlock_ptr(ptdesc)) at:
[<ffffffff821aeb0a>] spin_unlock include/linux/spinlock.h:389 [inline]
[<ffffffff821aeb0a>] pt_range_walk+0x25a/0x35a0 mm/pagewalk.c:1058
but there are no more locks to release!

other info that might help us debug this:
1 lock held by syz.1.18/5968:
 #0: ffff8881626b0340 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock_killable include/linux/mmap_lock.h:601 [inline]
 #0: ffff8881626b0340 (&mm->mmap_lock){++++}-{4:4}, at: do_pagemap_scan fs/proc/task_mmu.c:2746 [inline]
 #0: ffff8881626b0340 (&mm->mmap_lock){++++}-{4:4}, at: do_pagemap_cmd+0x618/0x4310 fs/proc/task_mmu.c:3131

stack backtrace:
CPU: 1 UID: 0 PID: 5968 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_unlock_imbalance_bug+0xdc/0xf0 kernel/locking/lockdep.c:5298
 __lock_release kernel/locking/lockdep.c:5537 [inline]
 lock_release+0x248/0x3d0 kernel/locking/lockdep.c:5889
 __raw_spin_unlock include/linux/spinlock_api_smp.h:167 [inline]
 _raw_spin_unlock+0x16/0x50 kernel/locking/spinlock.c:186
 spin_unlock include/linux/spinlock.h:389 [inline]
 pt_range_walk+0x25a/0x35a0 mm/pagewalk.c:1058
 pagemap_scan_walk fs/proc/task_mmu.c:2463 [inline]
 do_pagemap_scan fs/proc/task_mmu.c:2785 [inline]
 do_pagemap_cmd+0x3924/0x4310 fs/proc/task_mmu.c:3131
 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+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0ce439cdd9
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:00007f0ce5214028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f0ce4615fa0 RCX: 00007f0ce439cdd9
RDX: 0000200000000140 RSI: 00000000c0606610 RDI: 0000000000000004
RBP: 00007f0ce4432d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0ce4616038 R14: 00007f0ce4615fa0 R15: 00007fffbeb73768
 </TASK>


***

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:
[akpm@linux-foundation.org david@kernel.org david@redhat.com linux-kernel@vger.kernel.org linux-mm@kvack.org lorenzo.stoakes@oracle.com mhocko@suse.com muchun.song@linux.dev osalvador@suse.de vbabka@kernel.org]

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

* Re: [moderation/CI] Re: Implement a new generic pagewalk API
  2026-04-26 17:13 [moderation/CI] Re: Implement a new generic pagewalk API syzbot ci
@ 2026-04-26 19:00 ` Aleksandr Nogikh
  0 siblings, 0 replies; 6+ messages in thread
From: Aleksandr Nogikh @ 2026-04-26 19:00 UTC (permalink / raw)
  To: syzbot ci; +Cc: syzkaller-upstream-moderation, syzbot

#syz upstream

On Sun, Apr 26, 2026 at 7:13 PM syzbot ci
<syzbot+ci373afc5fb5256d32@syzkaller.appspotmail.com> wrote:
>
> syzbot ci has tested the following series
>
> [v2] Implement a new generic pagewalk API
> https://lore.kernel.org/all/20260426125719.24698-1-osalvador@suse.de
> * [RFC PATCH v2 1/7] mm: Add softleaf_from_pud
> * [RFC PATCH v2 2/7] mm: Add {pmd,pud}_huge_lock helper
> * [RFC PATCH v2 3/7] mm: Implement folio_pmd_batch
> * [RFC PATCH v2 4/7] mm: Implement pt_range_walk
> * [RFC PATCH v2 5/7] mm: Make /proc/pid/smaps use the new generic pagewalk API
> * [RFC PATCH v2 6/7] mm: Make /proc/pid/numa_maps use the new generic pagewalk API
> * [RFC PATCH v2 7/7] mm: Make /proc/pid/pagemap use the new generic pagewalk API
>
> and found the following issues:
> * KASAN: slab-out-of-bounds Write in pagemap_read
> * WARNING in __page_table_check_pmds_set
> * WARNING in pt_range_walk
> * WARNING: bad unlock balance in pt_range_walk
>
> Full report is available here:
> https://ci.syzbot.org/series/409219de-ca42-45a5-9204-0b315095160c
>
> ***
>
> KASAN: slab-out-of-bounds Write in pagemap_read
>
> tree:      mm-new
> URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/akpm/mm.git
> base:      819bd270abf9de3b7f306e233054b85a07c47820
> 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/0361816f-57b2-43e4-aef2-186d8d35fdc9/config
> syz repro: https://ci.syzbot.org/findings/7f740037-7398-46f2-aa01-a57caa186d06/syz_repro
>
> ==================================================================
> BUG: KASAN: slab-out-of-bounds in add_to_pagemap fs/proc/task_mmu.c:1776 [inline]
> BUG: KASAN: slab-out-of-bounds in pagemap_read_walk_range fs/proc/task_mmu.c:2949 [inline]
> BUG: KASAN: slab-out-of-bounds in pagemap_read+0x1d60/0x2810 fs/proc/task_mmu.c:3092
> Write of size 8 at addr ffff88816f1bd000 by task syz.1.18/5957
>
> CPU: 1 UID: 0 PID: 5957 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 mm/kasan/report.c:378 [inline]
>  print_report+0xba/0x230 mm/kasan/report.c:482
>  kasan_report+0x117/0x150 mm/kasan/report.c:595
>  add_to_pagemap fs/proc/task_mmu.c:1776 [inline]
>  pagemap_read_walk_range fs/proc/task_mmu.c:2949 [inline]
>  pagemap_read+0x1d60/0x2810 fs/proc/task_mmu.c:3092
>  vfs_read+0x20c/0xa70 fs/read_write.c:572
>  ksys_pread64 fs/read_write.c:765 [inline]
>  __do_sys_pread64 fs/read_write.c:773 [inline]
>  __se_sys_pread64 fs/read_write.c:770 [inline]
>  __x64_sys_pread64+0x199/0x230 fs/read_write.c:770
>  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: 0033:0x7f340679cdd9
> 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:00007f34075d2028 EFLAGS: 00000246 ORIG_RAX: 0000000000000011
> RAX: ffffffffffffffda RBX: 00007f3406a15fa0 RCX: 00007f340679cdd9
> RDX: 0000000000019020 RSI: 0000200000000200 RDI: 0000000000000003
> RBP: 00007f3406832d69 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000001000000000 R11: 0000000000000246 R12: 0000000000000000
> R13: 00007f3406a16038 R14: 00007f3406a15fa0 R15: 00007ffdb721f7e8
>  </TASK>
>
> Allocated by task 5957:
>  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:5339
>  kmalloc_noprof include/linux/slab.h:962 [inline]
>  kmalloc_array_noprof include/linux/slab.h:1109 [inline]
>  pagemap_read+0x27d/0x2810 fs/proc/task_mmu.c:3033
>  vfs_read+0x20c/0xa70 fs/read_write.c:572
>  ksys_pread64 fs/read_write.c:765 [inline]
>  __do_sys_pread64 fs/read_write.c:773 [inline]
>  __se_sys_pread64 fs/read_write.c:770 [inline]
>  __x64_sys_pread64+0x199/0x230 fs/read_write.c:770
>  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 ffff88816f1bc000
>  which belongs to the cache kmalloc-4k of size 4096
> The buggy address is located 0 bytes to the right of
>  allocated 4096-byte region [ffff88816f1bc000, ffff88816f1bd000)
>
> The buggy address belongs to the physical page:
> page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88816f1b8000 pfn:0x16f1b8
> head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
> flags: 0x57ff00000000240(workingset|head|node=1|zone=2|lastcpupid=0x7ff)
> page_type: f5(slab)
> raw: 057ff00000000240 ffff888100042140 ffff888160400a08 ffffea0005c6fe10
> raw: ffff88816f1b8000 0000000000040003 00000000f5000000 0000000000000000
> head: 057ff00000000240 ffff888100042140 ffff888160400a08 ffffea0005c6fe10
> head: ffff88816f1b8000 0000000000040003 00000000f5000000 0000000000000000
> head: 057ff00000000003 ffffea0005bc6e01 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 5715, tgid 5715 (rm), ts 50636400155, free_ts 46909302793
>  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:3255 [inline]
>  allocate_slab+0x77/0x660 mm/slub.c:3444
>  new_slab mm/slub.c:3502 [inline]
>  refill_objects+0x331/0x3c0 mm/slub.c:7134
>  refill_sheaf mm/slub.c:2804 [inline]
>  __pcs_replace_empty_main+0x2b9/0x620 mm/slub.c:4578
>  alloc_from_pcs mm/slub.c:4681 [inline]
>  slab_alloc_node mm/slub.c:4815 [inline]
>  __do_kmalloc_node mm/slub.c:5218 [inline]
>  __kmalloc_noprof+0x474/0x760 mm/slub.c:5231
>  kmalloc_noprof include/linux/slab.h:966 [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_unlink+0xaa/0xf0 security/tomoyo/tomoyo.c:162
>  security_path_unlink+0x15f/0x330 security/security.c:1457
>  filename_unlinkat+0x349/0x610 fs/namei.c:5537
>  __do_sys_unlink fs/namei.c:5575 [inline]
>  __se_sys_unlink+0x2e/0x140 fs/namei.c:5572
>  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 5257 tgid 5257 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:5532
>  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:4501 [inline]
>  slab_alloc_node mm/slub.c:4830 [inline]
>  kmem_cache_alloc_noprof+0x2bc/0x650 mm/slub.c:4837
>  alloc_filename fs/namei.c:142 [inline]
>  do_getname+0x2e/0x250 fs/namei.c:182
>  getname_flags fs/namei.c:225 [inline]
>  getname include/linux/fs.h:2512 [inline]
>  class_filename_constructor include/linux/fs.h:2539 [inline]
>  __do_sys_unlink fs/namei.c:5574 [inline]
>  __se_sys_unlink+0x1e/0x140 fs/namei.c:5572
>  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:
>  ffff88816f1bcf00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>  ffff88816f1bcf80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> >ffff88816f1bd000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>                    ^
>  ffff88816f1bd080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>  ffff88816f1bd100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> ==================================================================
>
>
> ***
>
> WARNING in __page_table_check_pmds_set
>
> tree:      mm-new
> URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/akpm/mm.git
> base:      819bd270abf9de3b7f306e233054b85a07c47820
> 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/0361816f-57b2-43e4-aef2-186d8d35fdc9/config
> syz repro: https://ci.syzbot.org/findings/f8fe52b4-cef7-4d25-8e60-cbbb1a4f4df5/syz_repro
>
> ------------[ cut here ]------------
> softleaf_cached_writable(entry)
> WARNING: mm/page_table_check.c:227 at page_table_check_pmd_flags mm/page_table_check.c:227 [inline], CPU#1: syz.0.17/6022
> WARNING: mm/page_table_check.c:227 at __page_table_check_pmds_set+0x18e/0x340 mm/page_table_check.c:240, CPU#1: syz.0.17/6022
> Modules linked in:
> CPU: 1 UID: 0 PID: 6022 Comm: syz.0.17 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
> RIP: 0010:page_table_check_pmd_flags mm/page_table_check.c:227 [inline]
> RIP: 0010:__page_table_check_pmds_set+0x18e/0x340 mm/page_table_check.c:240
> Code: 89 fe e8 85 44 89 ff 48 b8 00 00 00 00 00 00 00 94 4c 01 f8 48 c1 e8 3b 0f 94 c0 4d 39 e5 76 0f 84 c0 74 0b e8 83 3f 89 ff 90 <0f> 0b 90 eb 05 e8 78 3f 89 ff 31 ff 89 ee e8 af 43 89 ff 41 89 ef
> RSP: 0018:ffffc90003ce7af8 EFLAGS: 00010293
> RAX: ffffffff823c4d7d RBX: ffff888111416001 RCX: ffff88816cbd1d00
> RDX: 0000000000000000 RSI: 6c00000000000000 RDI: 6c00000000000000
> RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000003
> R10: 0000000000000002 R11: 0000000000000000 R12: c7fffffffffffffe
> R13: dfffffffdc9bfe06 R14: ffff888111416008 R15: 6c00000000000000
> FS:  00007ff0386af6c0(0000) GS:ffff8882a9466000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000555574a1a9e8 CR3: 00000001063c6000 CR4: 00000000000006f0
> Call Trace:
>  <TASK>
>  page_table_check_pmds_set include/linux/page_table_check.h:92 [inline]
>  set_pmd_at arch/x86/include/asm/pgtable.h:1234 [inline]
>  make_uffd_wp_pmd fs/proc/task_mmu.c:1903 [inline]
>  pagemap_scan_walk fs/proc/task_mmu.c:2631 [inline]
>  do_pagemap_scan fs/proc/task_mmu.c:2785 [inline]
>  do_pagemap_cmd+0x3bd8/0x4310 fs/proc/task_mmu.c:3131
>  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+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
>  entry_SYSCALL_64_after_hwframe+0x77/0x7f
> RIP: 0033:0x7ff03779cdd9
> 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:00007ff0386af028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
> RAX: ffffffffffffffda RBX: 00007ff037a16090 RCX: 00007ff03779cdd9
> RDX: 00002000000001c0 RSI: 00000000c0606610 RDI: 0000000000000003
> RBP: 00007ff037832d69 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> R13: 00007ff037a16128 R14: 00007ff037a16090 R15: 00007ffd47ec5488
>  </TASK>
>
>
> ***
>
> WARNING in pt_range_walk
>
> tree:      mm-new
> URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/akpm/mm.git
> base:      819bd270abf9de3b7f306e233054b85a07c47820
> 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/0361816f-57b2-43e4-aef2-186d8d35fdc9/config
> syz repro: https://ci.syzbot.org/findings/02bfe437-a81f-4510-9fff-4b769eb9a0a4/syz_repro
>
> ------------[ cut here ]------------
> next_addr < vma->vm_start || next_addr >= vma->vm_end
> WARNING: mm/pagewalk.c:1052 at pt_range_walk+0x14e/0x35a0 mm/pagewalk.c:1052, CPU#1: syz.2.19/6013
> Modules linked in:
> CPU: 1 UID: 0 PID: 6013 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
> RIP: 0010:pt_range_walk+0x14e/0x35a0 mm/pagewalk.c:1052
> Code: 74 08 48 89 df e8 12 1a 15 00 49 89 de 48 8b 1b 48 8b 7c 24 10 48 89 de e8 6f a5 aa ff 48 39 5c 24 10 73 13 e8 03 a3 aa ff 90 <0f> 0b 90 b8 01 00 00 00 e9 88 2b 00 00 49 8d 5e 08 48 89 d8 48 c1
> RSP: 0018:ffffc90003d37920 EFLAGS: 00010293
> RAX: ffffffff821b11f0 RBX: 0000200000800000 RCX: ffff8881134f5700
> RDX: 0000000000000000 RSI: 0000200000800000 RDI: 0000200000800000
> RBP: ffffc90003d37b30 R08: 00000000000000ff R09: 1ffff1102dc8b830
> R10: dffffc0000000000 R11: ffffed102dc8b831 R12: ffff8881709b1800
> R13: dffffc0000000000 R14: ffff8881709b1800 R15: 0000200000800000
> FS:  00007f33141ff6c0(0000) GS:ffff8882a9466000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007f331344f0d1 CR3: 000000017150e000 CR4: 00000000000006f0
> Call Trace:
>  <TASK>
>  pagemap_scan_walk fs/proc/task_mmu.c:2463 [inline]
>  do_pagemap_scan fs/proc/task_mmu.c:2785 [inline]
>  do_pagemap_cmd+0x3924/0x4310 fs/proc/task_mmu.c:3131
>  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+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
>  entry_SYSCALL_64_after_hwframe+0x77/0x7f
> RIP: 0033:0x7f331339cdd9
> 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:00007f33141ff028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
> RAX: ffffffffffffffda RBX: 00007f3313615fa0 RCX: 00007f331339cdd9
> RDX: 0000200000000140 RSI: 00000000c0606610 RDI: 0000000000000003
> RBP: 00007f3313432d69 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> R13: 00007f3313616038 R14: 00007f3313615fa0 R15: 00007fff980e14d8
>  </TASK>
>
>
> ***
>
> WARNING: bad unlock balance in pt_range_walk
>
> tree:      mm-new
> URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/akpm/mm.git
> base:      819bd270abf9de3b7f306e233054b85a07c47820
> 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/0361816f-57b2-43e4-aef2-186d8d35fdc9/config
> syz repro: https://ci.syzbot.org/findings/1e53935d-6673-468b-905d-88da8f1e39f3/syz_repro
>
> loop1: detected capacity change from 0 to 4096
> =====================================
> WARNING: bad unlock balance detected!
> syzkaller #0 Not tainted
> -------------------------------------
> syz.1.18/5968 is trying to release lock (ptlock_ptr(ptdesc)) at:
> [<ffffffff821aeb0a>] spin_unlock include/linux/spinlock.h:389 [inline]
> [<ffffffff821aeb0a>] pt_range_walk+0x25a/0x35a0 mm/pagewalk.c:1058
> but there are no more locks to release!
>
> other info that might help us debug this:
> 1 lock held by syz.1.18/5968:
>  #0: ffff8881626b0340 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock_killable include/linux/mmap_lock.h:601 [inline]
>  #0: ffff8881626b0340 (&mm->mmap_lock){++++}-{4:4}, at: do_pagemap_scan fs/proc/task_mmu.c:2746 [inline]
>  #0: ffff8881626b0340 (&mm->mmap_lock){++++}-{4:4}, at: do_pagemap_cmd+0x618/0x4310 fs/proc/task_mmu.c:3131
>
> stack backtrace:
> CPU: 1 UID: 0 PID: 5968 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_unlock_imbalance_bug+0xdc/0xf0 kernel/locking/lockdep.c:5298
>  __lock_release kernel/locking/lockdep.c:5537 [inline]
>  lock_release+0x248/0x3d0 kernel/locking/lockdep.c:5889
>  __raw_spin_unlock include/linux/spinlock_api_smp.h:167 [inline]
>  _raw_spin_unlock+0x16/0x50 kernel/locking/spinlock.c:186
>  spin_unlock include/linux/spinlock.h:389 [inline]
>  pt_range_walk+0x25a/0x35a0 mm/pagewalk.c:1058
>  pagemap_scan_walk fs/proc/task_mmu.c:2463 [inline]
>  do_pagemap_scan fs/proc/task_mmu.c:2785 [inline]
>  do_pagemap_cmd+0x3924/0x4310 fs/proc/task_mmu.c:3131
>  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+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
>  entry_SYSCALL_64_after_hwframe+0x77/0x7f
> RIP: 0033:0x7f0ce439cdd9
> 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:00007f0ce5214028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
> RAX: ffffffffffffffda RBX: 00007f0ce4615fa0 RCX: 00007f0ce439cdd9
> RDX: 0000200000000140 RSI: 00000000c0606610 RDI: 0000000000000004
> RBP: 00007f0ce4432d69 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> R13: 00007f0ce4616038 R14: 00007f0ce4615fa0 R15: 00007fffbeb73768
>  </TASK>
>
>
> ***
>
> 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:
> [akpm@linux-foundation.org david@kernel.org david@redhat.com linux-kernel@vger.kernel.org linux-mm@kvack.org lorenzo.stoakes@oracle.com mhocko@suse.com muchun.song@linux.dev osalvador@suse.de vbabka@kernel.org]
>
> If the report looks fine to you, reply with:
> #syz upstream
>
> If the report is a false positive, reply with
> #syz invalid
>
> --
> You received this message because you are subscribed to the Google Groups "syzkaller-upstream-moderation" group.
> To unsubscribe from this group and stop receiving emails from it, send an email to syzkaller-upstream-moderation+unsubscribe@googlegroups.com.
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^ permalink raw reply	[flat|nested] 6+ messages in thread

* [moderation/CI] Re: Implement a new generic pagewalk API
@ 2026-05-25 21:29 syzbot ci
  2026-05-26  5:46 ` Aleksandr Nogikh
  0 siblings, 1 reply; 6+ messages in thread
From: syzbot ci @ 2026-05-25 21:29 UTC (permalink / raw)
  To: syzkaller-upstream-moderation; +Cc: syzbot

syzbot ci has tested the following series

[v3] Implement a new generic pagewalk API
https://lore.kernel.org/all/20260525165528.184397-1-osalvador@suse.de
* [RFC PATCH v3 1/8] mm: Add softleaf_from_pud
* [RFC PATCH v3 2/8] mm: Add {pmd,pud}_huge_lock helper
* [RFC PATCH v3 3/8] mm: Implement folio_pmd_batch
* [RFC PATCH v3 4/8] mm: Implement pt_range_walk
* [RFC PATCH v3 5/8] mm: Make /proc/pid/smaps use the new generic pagewalk API
* [RFC PATCH v3 6/8] mm: Make /proc/pid/numa_maps use the new generic pagewalk API
* [RFC PATCH v3 7/8] mm: Make /proc/pid/pagemap use the new generic pagewalk API
* [RFC PATCH v3 8/8] mm: Make /proc/pid/clear_refs use the new generic pagewalk API

and found the following issue:
general protection fault in clear_refs_write

Full report is available here:
https://ci.syzbot.org/series/0beab2d0-9d88-4288-ac81-b294e51c057d

***

general protection fault in clear_refs_write

tree:      mm-new
URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/akpm/mm.git
base:      5200f5f493f79f14bbdc349e402a40dfb32f23c8
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/8f20e88b-808c-4c60-9b8e-0af4c9fce5ff/config
syz repro: https://ci.syzbot.org/findings/634b1f0a-cf64-4607-928a-ef3ad40f765c/syz_repro

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 1 UID: 0 PID: 5863 Comm: syz.0.17 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
RIP: 0010:clear_soft_dirty_pmd fs/proc/task_mmu.c:1545 [inline]
RIP: 0010:clear_refs_pmd_range fs/proc/task_mmu.c:1581 [inline]
RIP: 0010:clear_refs_write+0xaa7/0x1590 fs/proc/task_mmu.c:1721
Code: 44 24 10 4c 8b bc 24 20 02 00 00 83 7c 24 28 04 0f 85 aa 05 00 00 48 8b 9c 24 08 02 00 00 48 89 d8 48 c1 e8 03 48 89 44 24 58 <42> 80 3c 20 00 74 08 48 89 df e8 fa 2c c6 ff 4c 8b 23 4c 89 e6 48
RSP: 0018:ffffc900037bf960 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000005
RDX: ffffffff826b21ce RSI: ffffffff8eb17b50 RDI: 0000000000000001
RBP: ffffc900037bfc10 R08: ffff8881047c0000 R09: 0000000000000002
R10: 0000000000000002 R11: 0000000000000000 R12: dffffc0000000000
R13: fffff520006f7f40 R14: ffff8881141c8308 R15: ffff8881141c8300
FS:  00007ff8ffc1d6c0(0000) GS:ffff8882a928a000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b33e63fff CR3: 000000010476e000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 do_loop_readv_writev fs/read_write.c:852 [inline]
 vfs_writev+0x4bd/0x990 fs/read_write.c:1061
 do_writev+0x154/0x2e0 fs/read_write.c:1105
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff8fed9ce59
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:00007ff8ffc1d028 EFLAGS: 00000246 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 00007ff8ff015fa0 RCX: 00007ff8fed9ce59
RDX: 0000000000000001 RSI: 00002000000000c0 RDI: 0000000000000003
RBP: 00007ff8fee32d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff8ff016038 R14: 00007ff8ff015fa0 R15: 00007fffd02796e8
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:clear_soft_dirty_pmd fs/proc/task_mmu.c:1545 [inline]
RIP: 0010:clear_refs_pmd_range fs/proc/task_mmu.c:1581 [inline]
RIP: 0010:clear_refs_write+0xaa7/0x1590 fs/proc/task_mmu.c:1721
Code: 44 24 10 4c 8b bc 24 20 02 00 00 83 7c 24 28 04 0f 85 aa 05 00 00 48 8b 9c 24 08 02 00 00 48 89 d8 48 c1 e8 03 48 89 44 24 58 <42> 80 3c 20 00 74 08 48 89 df e8 fa 2c c6 ff 4c 8b 23 4c 89 e6 48
RSP: 0018:ffffc900037bf960 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000005
RDX: ffffffff826b21ce RSI: ffffffff8eb17b50 RDI: 0000000000000001
RBP: ffffc900037bfc10 R08: ffff8881047c0000 R09: 0000000000000002
R10: 0000000000000002 R11: 0000000000000000 R12: dffffc0000000000
R13: fffff520006f7f40 R14: ffff8881141c8308 R15: ffff8881141c8300
FS:  00007ff8ffc1d6c0(0000) GS:ffff8882a928a000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b34063fff CR3: 000000010476e000 CR4: 00000000000006f0
----------------
Code disassembly (best guess):
   0:	44 24 10             	rex.R and $0x10,%al
   3:	4c 8b bc 24 20 02 00 	mov    0x220(%rsp),%r15
   a:	00
   b:	83 7c 24 28 04       	cmpl   $0x4,0x28(%rsp)
  10:	0f 85 aa 05 00 00    	jne    0x5c0
  16:	48 8b 9c 24 08 02 00 	mov    0x208(%rsp),%rbx
  1d:	00
  1e:	48 89 d8             	mov    %rbx,%rax
  21:	48 c1 e8 03          	shr    $0x3,%rax
  25:	48 89 44 24 58       	mov    %rax,0x58(%rsp)
* 2a:	42 80 3c 20 00       	cmpb   $0x0,(%rax,%r12,1) <-- trapping instruction
  2f:	74 08                	je     0x39
  31:	48 89 df             	mov    %rbx,%rdi
  34:	e8 fa 2c c6 ff       	call   0xffc62d33
  39:	4c 8b 23             	mov    (%rbx),%r12
  3c:	4c 89 e6             	mov    %r12,%rsi
  3f:	48                   	rex.W


***

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:
[akpm@linux-foundation.org david@kernel.org david@redhat.com linux-kernel@vger.kernel.org linux-mm@kvack.org lorenzo.stoakes@oracle.com mhocko@suse.com muchun.song@linux.dev osalvador@suse.de vbabka@kernel.org]

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

* Re: [moderation/CI] Re: Implement a new generic pagewalk API
  2026-05-25 21:29 syzbot ci
@ 2026-05-26  5:46 ` Aleksandr Nogikh
  0 siblings, 0 replies; 6+ messages in thread
From: Aleksandr Nogikh @ 2026-05-26  5:46 UTC (permalink / raw)
  To: syzbot ci; +Cc: syzkaller-upstream-moderation, syzbot

#syz upstream

On Mon, May 25, 2026 at 11:29 PM syzbot ci
<syzbot+cib37dbe4691931542@syzkaller.appspotmail.com> wrote:
>
> syzbot ci has tested the following series
>
> [v3] Implement a new generic pagewalk API
> https://lore.kernel.org/all/20260525165528.184397-1-osalvador@suse.de
> * [RFC PATCH v3 1/8] mm: Add softleaf_from_pud
> * [RFC PATCH v3 2/8] mm: Add {pmd,pud}_huge_lock helper
> * [RFC PATCH v3 3/8] mm: Implement folio_pmd_batch
> * [RFC PATCH v3 4/8] mm: Implement pt_range_walk
> * [RFC PATCH v3 5/8] mm: Make /proc/pid/smaps use the new generic pagewalk API
> * [RFC PATCH v3 6/8] mm: Make /proc/pid/numa_maps use the new generic pagewalk API
> * [RFC PATCH v3 7/8] mm: Make /proc/pid/pagemap use the new generic pagewalk API
> * [RFC PATCH v3 8/8] mm: Make /proc/pid/clear_refs use the new generic pagewalk API
>
> and found the following issue:
> general protection fault in clear_refs_write
>
> Full report is available here:
> https://ci.syzbot.org/series/0beab2d0-9d88-4288-ac81-b294e51c057d
>
> ***
>
> general protection fault in clear_refs_write
>
> tree:      mm-new
> URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/akpm/mm.git
> base:      5200f5f493f79f14bbdc349e402a40dfb32f23c8
> 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/8f20e88b-808c-4c60-9b8e-0af4c9fce5ff/config
> syz repro: https://ci.syzbot.org/findings/634b1f0a-cf64-4607-928a-ef3ad40f765c/syz_repro
>
> Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN PTI
> KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
> CPU: 1 UID: 0 PID: 5863 Comm: syz.0.17 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
> RIP: 0010:clear_soft_dirty_pmd fs/proc/task_mmu.c:1545 [inline]
> RIP: 0010:clear_refs_pmd_range fs/proc/task_mmu.c:1581 [inline]
> RIP: 0010:clear_refs_write+0xaa7/0x1590 fs/proc/task_mmu.c:1721
> Code: 44 24 10 4c 8b bc 24 20 02 00 00 83 7c 24 28 04 0f 85 aa 05 00 00 48 8b 9c 24 08 02 00 00 48 89 d8 48 c1 e8 03 48 89 44 24 58 <42> 80 3c 20 00 74 08 48 89 df e8 fa 2c c6 ff 4c 8b 23 4c 89 e6 48
> RSP: 0018:ffffc900037bf960 EFLAGS: 00010246
> RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000005
> RDX: ffffffff826b21ce RSI: ffffffff8eb17b50 RDI: 0000000000000001
> RBP: ffffc900037bfc10 R08: ffff8881047c0000 R09: 0000000000000002
> R10: 0000000000000002 R11: 0000000000000000 R12: dffffc0000000000
> R13: fffff520006f7f40 R14: ffff8881141c8308 R15: ffff8881141c8300
> FS:  00007ff8ffc1d6c0(0000) GS:ffff8882a928a000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000001b33e63fff CR3: 000000010476e000 CR4: 00000000000006f0
> Call Trace:
>  <TASK>
>  do_loop_readv_writev fs/read_write.c:852 [inline]
>  vfs_writev+0x4bd/0x990 fs/read_write.c:1061
>  do_writev+0x154/0x2e0 fs/read_write.c:1105
>  do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
>  do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
>  entry_SYSCALL_64_after_hwframe+0x77/0x7f
> RIP: 0033:0x7ff8fed9ce59
> 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:00007ff8ffc1d028 EFLAGS: 00000246 ORIG_RAX: 0000000000000014
> RAX: ffffffffffffffda RBX: 00007ff8ff015fa0 RCX: 00007ff8fed9ce59
> RDX: 0000000000000001 RSI: 00002000000000c0 RDI: 0000000000000003
> RBP: 00007ff8fee32d6f R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> R13: 00007ff8ff016038 R14: 00007ff8ff015fa0 R15: 00007fffd02796e8
>  </TASK>
> Modules linked in:
> ---[ end trace 0000000000000000 ]---
> RIP: 0010:clear_soft_dirty_pmd fs/proc/task_mmu.c:1545 [inline]
> RIP: 0010:clear_refs_pmd_range fs/proc/task_mmu.c:1581 [inline]
> RIP: 0010:clear_refs_write+0xaa7/0x1590 fs/proc/task_mmu.c:1721
> Code: 44 24 10 4c 8b bc 24 20 02 00 00 83 7c 24 28 04 0f 85 aa 05 00 00 48 8b 9c 24 08 02 00 00 48 89 d8 48 c1 e8 03 48 89 44 24 58 <42> 80 3c 20 00 74 08 48 89 df e8 fa 2c c6 ff 4c 8b 23 4c 89 e6 48
> RSP: 0018:ffffc900037bf960 EFLAGS: 00010246
> RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000005
> RDX: ffffffff826b21ce RSI: ffffffff8eb17b50 RDI: 0000000000000001
> RBP: ffffc900037bfc10 R08: ffff8881047c0000 R09: 0000000000000002
> R10: 0000000000000002 R11: 0000000000000000 R12: dffffc0000000000
> R13: fffff520006f7f40 R14: ffff8881141c8308 R15: ffff8881141c8300
> FS:  00007ff8ffc1d6c0(0000) GS:ffff8882a928a000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000001b34063fff CR3: 000000010476e000 CR4: 00000000000006f0
> ----------------
> Code disassembly (best guess):
>    0:   44 24 10                rex.R and $0x10,%al
>    3:   4c 8b bc 24 20 02 00    mov    0x220(%rsp),%r15
>    a:   00
>    b:   83 7c 24 28 04          cmpl   $0x4,0x28(%rsp)
>   10:   0f 85 aa 05 00 00       jne    0x5c0
>   16:   48 8b 9c 24 08 02 00    mov    0x208(%rsp),%rbx
>   1d:   00
>   1e:   48 89 d8                mov    %rbx,%rax
>   21:   48 c1 e8 03             shr    $0x3,%rax
>   25:   48 89 44 24 58          mov    %rax,0x58(%rsp)
> * 2a:   42 80 3c 20 00          cmpb   $0x0,(%rax,%r12,1) <-- trapping instruction
>   2f:   74 08                   je     0x39
>   31:   48 89 df                mov    %rbx,%rdi
>   34:   e8 fa 2c c6 ff          call   0xffc62d33
>   39:   4c 8b 23                mov    (%rbx),%r12
>   3c:   4c 89 e6                mov    %r12,%rsi
>   3f:   48                      rex.W
>
>
> ***
>
> 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:
> [akpm@linux-foundation.org david@kernel.org david@redhat.com linux-kernel@vger.kernel.org linux-mm@kvack.org lorenzo.stoakes@oracle.com mhocko@suse.com muchun.song@linux.dev osalvador@suse.de vbabka@kernel.org]
>
> If the report looks fine to you, reply with:
> #syz upstream
>
> If the report is a false positive, reply with
> #syz invalid
>
> --
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^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2026-05-26  5:47 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2026-04-26 17:13 [moderation/CI] Re: Implement a new generic pagewalk API syzbot ci
2026-04-26 19:00 ` Aleksandr Nogikh
  -- strict thread matches above, loose matches on Subject: below --
2026-05-25 21:29 syzbot ci
2026-05-26  5:46 ` Aleksandr Nogikh
2026-04-12 22:28 syzbot ci
2026-04-13  7:35 ` Aleksandr Nogikh

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