Re: [moderation/CI] Re: mm: fix inode UAF when splitting a file folio past EOF

#syz upstream

On Wed, Jul 15, 2026 at 2:21 AM syzbot ci
<[email protected]> wrote:
>
> syzbot ci has tested the following series
>
> [v2] mm: fix inode UAF when splitting a file folio past EOF
> https://lore.kernel.org/all/[email protected]
> * [PATCH v2 1/5] mm/memory-failure: keep the folio, not the poisoned subpage, locked across split
> * [PATCH v2 2/5] mm/huge_memory: refuse to split a file folio when the anchor is beyond EOF
> * [PATCH v2 3/5] mm/huge_memory: remove unused split_huge_page_to_order()
> * [PATCH v2 4/5] mm/huge_memory: remove unused can_split_folio()
> * [PATCH v2 5/5] mm/huge_memory: fold split_folio_to_list_to_order() into split_folio_to_order()
>
> and found the following issues:
> * kernel BUG in __page_table_check_zero
> * kernel BUG in folio_isolate_lru
> * kernel BUG in memory_failure
>
> Full report is available here:
> https://ci.syzbot.org/series/6cad3430-1f9b-4a56-b60a-ef3ed2833e15
>
> ***
>
> kernel BUG in __page_table_check_zero
>
> tree:      bpf
> URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/bpf/bpf.git
> base:      0e35b9b6ec0ffcc5e23cbdec09f5c622ad532b53
> 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/8d6a621e-aae6-4f99-8e0e-d0e02ddbed71/config
> syz repro: https://ci.syzbot.org/findings/1619ac56-823a-4cc2-975b-bbb1c1742447/syz_repro
>
> Soft offlining pfn 0x120f0e at process virtual address 0x20000010e000
> ------------[ cut here ]------------
> kernel BUG at mm/page_table_check.c:142!
> Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
> CPU: 0 UID: 0 PID: 5870 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:__page_table_check_zero+0x416/0x430 mm/page_table_check.c:142
> Code: f3 ff e9 4e fc ff ff e8 78 70 85 ff 89 ea be 01 00 00 00 48 c7 c7 a0 c4 ac 8e e8 45 29 b7 02 e9 48 fd ff ff e8 5b 70 85 ff 90 <0f> 0b e8 53 70 85 ff 90 0f 0b e8 4b 70 85 ff 90 0f 0b 0f 1f 84 00
> RSP: 0018:ffffc900017e7948 EFLAGS: 00010293
> RAX: ffffffff8240f325 RBX: ffff88810544b4a8 RCX: ffff88810c68bb80
> RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
> RBP: 0000000000000001 R08: ffff88810544b4ab R09: 1ffff11020a89695
> R10: dffffc0000000000 R11: ffffed1020a89696 R12: 0000000000000001
> R13: ffff88810544b460 R14: 0000000000000000 R15: 0000000000000001
> FS:  00007fb17e6b86c0(0000) GS:ffff88818dc0e000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007f2353670000 CR3: 0000000109db2000 CR4: 00000000000006f0
> Call Trace:
>  <TASK>
>  __folio_put+0x4b3/0x590 mm/swap.c:112
>  folio_put include/linux/mm.h:2124 [inline]
>  put_page include/linux/mm.h:2193 [inline]
>  page_handle_poison+0x35d/0x4a0 mm/memory-failure.c:204
>  soft_offline_in_use_page mm/memory-failure.c:2861 [inline]
>  soft_offline_page+0xd1d/0x1560 mm/memory-failure.c:2952
>  madvise_inject_error mm/madvise.c:1476 [inline]
>  madvise_do_behavior+0x319/0x930 mm/madvise.c:1897
>  do_madvise+0x327/0x3a0 mm/madvise.c:2005
>  __do_sys_madvise mm/madvise.c:2014 [inline]
>  __se_sys_madvise mm/madvise.c:2012 [inline]
>  __x64_sys_madvise+0xa6/0xc0 mm/madvise.c:2012
>  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: 0033:0x7fb17d79ce59
> 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:00007fb17e6b8028 EFLAGS: 00000246 ORIG_RAX: 000000000000001c
> RAX: ffffffffffffffda RBX: 00007fb17da15fa0 RCX: 00007fb17d79ce59
> RDX: 0000000000000065 RSI: 0000000000002000 RDI: 000020000010e000
> RBP: 00007fb17d832e6f R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> R13: 00007fb17da16038 R14: 00007fb17da15fa0 R15: 00007ffd7e9be1d8
>  </TASK>
> Modules linked in:
> ---[ end trace 0000000000000000 ]---
> RIP: 0010:__page_table_check_zero+0x416/0x430 mm/page_table_check.c:142
> Code: f3 ff e9 4e fc ff ff e8 78 70 85 ff 89 ea be 01 00 00 00 48 c7 c7 a0 c4 ac 8e e8 45 29 b7 02 e9 48 fd ff ff e8 5b 70 85 ff 90 <0f> 0b e8 53 70 85 ff 90 0f 0b e8 4b 70 85 ff 90 0f 0b 0f 1f 84 00
> RSP: 0018:ffffc900017e7948 EFLAGS: 00010293
> RAX: ffffffff8240f325 RBX: ffff88810544b4a8 RCX: ffff88810c68bb80
> RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
> RBP: 0000000000000001 R08: ffff88810544b4ab R09: 1ffff11020a89695
> R10: dffffc0000000000 R11: ffffed1020a89696 R12: 0000000000000001
> R13: ffff88810544b460 R14: 0000000000000000 R15: 0000000000000001
> FS:  00007fb17e6b86c0(0000) GS:ffff88818dc0e000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007fb17d7ea540 CR3: 0000000109db2000 CR4: 00000000000006f0
>
>
> ***
>
> kernel BUG in folio_isolate_lru
>
> tree:      bpf
> URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/bpf/bpf.git
> base:      0e35b9b6ec0ffcc5e23cbdec09f5c622ad532b53
> 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/8d6a621e-aae6-4f99-8e0e-d0e02ddbed71/config
> syz repro: https://ci.syzbot.org/findings/7857300c-5c56-4b88-9f60-6f1f3603e3f1/syz_repro
>
>  do_madvise+0x327/0x3a0 mm/madvise.c:2005
>  __do_sys_madvise mm/madvise.c:2014 [inline]
>  __se_sys_madvise mm/madvise.c:2012 [inline]
>  __x64_sys_madvise+0xa6/0xc0 mm/madvise.c:2012
>  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
> ------------[ cut here ]------------
> kernel BUG at mm/vmscan.c:1803!
> Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
> CPU: 0 UID: 0 PID: 5810 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:folio_isolate_lru+0x8ad/0x990 mm/vmscan.c:1803
> Code: 38 c1 0f 8c 75 fd ff ff 4c 89 f7 e8 ad 0e 28 00 e9 68 fd ff ff e8 d3 2b ba ff 4c 89 f7 48 c7 c6 20 5f d8 8b e8 84 d9 1b ff 90 <0f> 0b e8 bc 2b ba ff 4c 89 f7 48 c7 c6 60 8e d8 8b e8 6d d9 1b ff
> RSP: 0018:ffffc90003c678d8 EFLAGS: 00010246
> RAX: 2554150cb728ac00 RBX: 0000000000000000 RCX: 0000000000000000
> RDX: 0000000000000006 RSI: ffffffff8dfe9eba RDI: 00000000ffffffff
> RBP: 1ffffd40000f9d26 R08: ffffffff90334ef7 R09: 1ffffffff20669de
> R10: dffffc0000000000 R11: fffffbfff20669df R12: dffffc0000000000
> R13: 0000000000100010 R14: ffffea00007ce900 R15: ffffea00007ce934
> FS:  00007fa1793946c0(0000) GS:ffff88818dc0e000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00005640d3daa058 CR3: 00000001696d8000 CR4: 00000000000006f0
> Call Trace:
>  <TASK>
>  delete_from_lru_cache+0x1a/0x1e0 mm/memory-failure.c:900
>  me_pagecache_clean+0x58/0x230 mm/memory-failure.c:1015
>  page_action mm/memory-failure.c:1298 [inline]
>  identify_page_state+0x13c/0x190 mm/memory-failure.c:1649
>  memory_failure+0x2fff/0x3380 mm/memory-failure.c:2548
>  madvise_inject_error mm/madvise.c:1480 [inline]
>  madvise_do_behavior+0x344/0x930 mm/madvise.c:1897
>  do_madvise+0x327/0x3a0 mm/madvise.c:2005
>  __do_sys_madvise mm/madvise.c:2014 [inline]
>  __se_sys_madvise mm/madvise.c:2012 [inline]
>  __x64_sys_madvise+0xa6/0xc0 mm/madvise.c:2012
>  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: 0033:0x7fa17859ce59
> 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:00007fa179394028 EFLAGS: 00000246 ORIG_RAX: 000000000000001c
> RAX: ffffffffffffffda RBX: 00007fa178815fa0 RCX: 00007fa17859ce59
> RDX: 0000000000000064 RSI: 0000000000002000 RDI: 00002000005a4000
> RBP: 00007fa178632e6f R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> R13: 00007fa178816038 R14: 00007fa178815fa0 R15: 00007fff254e3208
>  </TASK>
> Modules linked in:
> ---[ end trace 0000000000000000 ]---
> RIP: 0010:folio_isolate_lru+0x8ad/0x990 mm/vmscan.c:1803
> Code: 38 c1 0f 8c 75 fd ff ff 4c 89 f7 e8 ad 0e 28 00 e9 68 fd ff ff e8 d3 2b ba ff 4c 89 f7 48 c7 c6 20 5f d8 8b e8 84 d9 1b ff 90 <0f> 0b e8 bc 2b ba ff 4c 89 f7 48 c7 c6 60 8e d8 8b e8 6d d9 1b ff
> RSP: 0018:ffffc90003c678d8 EFLAGS: 00010246
> RAX: 2554150cb728ac00 RBX: 0000000000000000 RCX: 0000000000000000
> RDX: 0000000000000006 RSI: ffffffff8dfe9eba RDI: 00000000ffffffff
> RBP: 1ffffd40000f9d26 R08: ffffffff90334ef7 R09: 1ffffffff20669de
> R10: dffffc0000000000 R11: fffffbfff20669df R12: dffffc0000000000
> R13: 0000000000100010 R14: ffffea00007ce900 R15: ffffea00007ce934
> FS:  00007fa1793946c0(0000) GS:ffff88818dc0e000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00005640d3daa058 CR3: 00000001696d8000 CR4: 00000000000006f0
>
>
> ***
>
> kernel BUG in memory_failure
>
> tree:      bpf
> URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/bpf/bpf.git
> base:      0e35b9b6ec0ffcc5e23cbdec09f5c622ad532b53
> 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/8d6a621e-aae6-4f99-8e0e-d0e02ddbed71/config
> syz repro: https://ci.syzbot.org/findings/6feafe6c-6796-475f-9aca-225a9d35747c/syz_repro
>
>  do_madvise+0x327/0x3a0 mm/madvise.c:2005
>  __do_sys_madvise mm/madvise.c:2014 [inline]
>  __se_sys_madvise mm/madvise.c:2012 [inline]
>  __x64_sys_madvise+0xa6/0xc0 mm/madvise.c:2012
>  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
> ------------[ cut here ]------------
> kernel BUG at mm/memory-failure.c:2483!
> Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
> CPU: 1 UID: 0 PID: 5850 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:memory_failure+0x3373/0x3380 mm/memory-failure.c:2483
> Code: cb 87 ff 48 89 df 48 c7 c6 e0 a2 dd 8b e8 45 79 e9 fe 90 0f 0b e8 7d cb 87 ff 4c 89 f7 48 c7 c6 40 93 dd 8b e8 2e 79 e9 fe 90 <0f> 0b 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90
> RSP: 0018:ffffc900036efa00 EFLAGS: 00010246
> RAX: 9a71b80f9d8a2200 RBX: 0000000000000000 RCX: 0000000000000000
> RDX: 0000000000000006 RSI: ffffffff8dfe9eba RDI: 00000000ffffffff
> RBP: ffffc900036efb90 R08: ffffffff90334ef7 R09: 1ffffffff20669de
> R10: dffffc0000000000 R11: fffffbfff20669df R12: ffffea00045f6ac0
> R13: ffffea00045f0008 R14: ffffea00045f6ac0 R15: 1ffff920006ddf54
> FS:  00007fed60fc56c0(0000) GS:ffff8882a920e000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007f3eee905440 CR3: 0000000165fdc000 CR4: 00000000000006f0
> Call Trace:
>  <TASK>
>  madvise_inject_error mm/madvise.c:1480 [inline]
>  madvise_do_behavior+0x344/0x930 mm/madvise.c:1897
>  do_madvise+0x327/0x3a0 mm/madvise.c:2005
>  __do_sys_madvise mm/madvise.c:2014 [inline]
>  __se_sys_madvise mm/madvise.c:2012 [inline]
>  __x64_sys_madvise+0xa6/0xc0 mm/madvise.c:2012
>  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: 0033:0x7fed6019ce59
> 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:00007fed60fc5028 EFLAGS: 00000246 ORIG_RAX: 000000000000001c
> RAX: ffffffffffffffda RBX: 00007fed60415fa0 RCX: 00007fed6019ce59
> RDX: 0000000000000064 RSI: 0000000000001000 RDI: 0000200000ffe000
> RBP: 00007fed60232e6f R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> R13: 00007fed60416038 R14: 00007fed60415fa0 R15: 00007ffc1c6c3eb8
>  </TASK>
> Modules linked in:
> ---[ end trace 0000000000000000 ]---
> RIP: 0010:memory_failure+0x3373/0x3380 mm/memory-failure.c:2483
> Code: cb 87 ff 48 89 df 48 c7 c6 e0 a2 dd 8b e8 45 79 e9 fe 90 0f 0b e8 7d cb 87 ff 4c 89 f7 48 c7 c6 40 93 dd 8b e8 2e 79 e9 fe 90 <0f> 0b 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90
> RSP: 0018:ffffc900036efa00 EFLAGS: 00010246
> RAX: 9a71b80f9d8a2200 RBX: 0000000000000000 RCX: 0000000000000000
> RDX: 0000000000000006 RSI: ffffffff8dfe9eba RDI: 00000000ffffffff
> RBP: ffffc900036efb90 R08: ffffffff90334ef7 R09: 1ffffffff20669de
> R10: dffffc0000000000 R11: fffffbfff20669df R12: ffffea00045f6ac0
> R13: ffffea00045f0008 R14: ffffea00045f6ac0 R15: 1ffff920006ddf54
> FS:  00007fed60fc56c0(0000) GS:ffff8882a920e000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000001b33863fff CR3: 0000000165fdc000 CR4: 00000000000006f0
>
>
> ***
>
> 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: [email protected]
>
> ---
> This report is generated by a bot. It may contain errors.
> syzbot ci engineers can be reached at [email protected].
>
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