Re: [moderation/CI] Re: iomap: follow the alignment requirement for iomap_dio_hole_iter()

Pimyn Girgis <[email protected]> Fri, 31 Jul 2026 13:39:04 +0200
Newsgroups dev.linux.lists.syzbot
Message-ID <CAJWNTGydQUh=8jg-UbLdc-BT-zF6MWb3N5qLGBeifcSpfcCKUg@mail.gmail.com>
#syz upstream


On Fri, Jul 31, 2026 at 1:38=E2=80=AFPM syzbot ci
<[email protected]> wrote:
>
> syzbot ci has tested the following series
>
> [v1] iomap: follow the alignment requirement for iomap_dio_hole_iter()
> https://lore.kernel.org/all/e69cc8a4a9c3f641b97872b50f04c397880077cd.1785=
[email protected]
> * [PATCH] iomap: follow the alignment requirement for iomap_dio_hole_iter=
()
>
> and found the following issue:
> general protection fault in __iomap_dio_rw
>
> Full report is available here:
> https://ci.syzbot.org/series/81e0fbae-4715-4d62-8e9e-bcd19e46b164
>
> ***
>
> general protection fault in __iomap_dio_rw
>
> tree:      vfs
> URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/vfs/v=
fs.git
> base:      70c2cbf8600c7d3a622b77e31136b83d6ac7d86c
> arch:      amd64
> compiler:  Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~e=
xp1~20260613092250.77), Debian LLD 22.1.8
> config:    https://ci.syzbot.org/builds/8d5fee65-291c-46a2-9f9a-d512f8fad=
82b/config
> syz repro: https://ci.syzbot.org/findings/c9f79a18-3316-44ec-b805-b805b1c=
49325/syz_repro
>
> loop0: rw=3D2049, sector=3D53248, nr_sectors =3D 976 limit=3D40427
> Oops: general protection fault, probably for non-canonical address 0xdfff=
fc0000000003: 0000 [#1] SMP KASAN PTI
> KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f]
> CPU: 0 UID: 0 PID: 5842 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(f=
ull)
> Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.=
16.2-1 04/01/2014
> RIP: 0010:bdev_get_queue include/linux/blkdev.h:1058 [inline]
> RIP: 0010:bdev_logical_block_size include/linux/blkdev.h:1403 [inline]
> RIP: 0010:iomap_dio_alignment fs/iomap/direct-io.c:415 [inline]
> RIP: 0010:iomap_dio_hole_iter fs/iomap/direct-io.c:595 [inline]
> RIP: 0010:iomap_dio_iter fs/iomap/direct-io.c:643 [inline]
> RIP: 0010:__iomap_dio_rw+0x1142/0x2130 fs/iomap/direct-io.c:815
> Code: e2 5a ff 83 e3 08 75 5c e8 ab de 5a ff 48 8b 9c 24 68 01 00 00 48 8=
3 c3 18 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74=
 08 48 89 df e8 d0 75 c8 ff 48 8b 1b b8 58 01 00 00
> RSP: 0018:ffffc90003fef560 EFLAGS: 00010206
> RAX: 0000000000000003 RBX: 0000000000000018 RCX: dffffc0000000000
> RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
> RBP: ffffc90003fef860 R08: ffff8881148d8fff R09: 0000000000000000
> R10: ffff8881148d8000 R11: ffffed102291b200 R12: 1ffff920007fdecc
> R13: 0000000000000000 R14: ffff888166b45340 R15: 0000000000001000
> FS:  00007fd77743d6c0(0000) GS:ffff88818d951000(0000) knlGS:0000000000000=
000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000200000078000 CR3: 000000011606a000 CR4: 00000000000006f0
> Call Trace:
>  <TASK>
>  f2fs_dio_read_iter fs/f2fs/file.c:4887 [inline]
>  f2fs_file_read_iter+0x60b/0x940 fs/f2fs/file.c:4950
>  copy_splice_read+0x5ff/0xaa0 fs/splice.c:362
>  do_splice_read fs/splice.c:979 [inline]
>  splice_direct_to_actor+0x4b6/0xcb0 fs/splice.c:1084
>  do_splice_direct_actor fs/splice.c:1202 [inline]
>  do_splice_direct+0x195/0x290 fs/splice.c:1228
>  do_sendfile+0x52e/0x7c0 fs/read_write.c:1371
>  __do_sys_sendfile64 fs/read_write.c:1432 [inline]
>  __se_sys_sendfile64+0x144/0x1a0 fs/read_write.c:1418
>  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: 0033:0x7fd77659df99
> Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f=
7 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:00007fd77743d028 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
> RAX: ffffffffffffffda RBX: 00007fd776825fa0 RCX: 00007fd77659df99
> RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000004
> RBP: 00007fd776634ec4 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000800000009 R11: 0000000000000246 R12: 0000000000000000
> R13: 00007fd776826038 R14: 00007fd776825fa0 R15: 00007fff168f4a18
>  </TASK>
> Modules linked in:
> ---[ end trace 0000000000000000 ]---
> RIP: 0010:bdev_get_queue include/linux/blkdev.h:1058 [inline]
> RIP: 0010:bdev_logical_block_size include/linux/blkdev.h:1403 [inline]
> RIP: 0010:iomap_dio_alignment fs/iomap/direct-io.c:415 [inline]
> RIP: 0010:iomap_dio_hole_iter fs/iomap/direct-io.c:595 [inline]
> RIP: 0010:iomap_dio_iter fs/iomap/direct-io.c:643 [inline]
> RIP: 0010:__iomap_dio_rw+0x1142/0x2130 fs/iomap/direct-io.c:815
> Code: e2 5a ff 83 e3 08 75 5c e8 ab de 5a ff 48 8b 9c 24 68 01 00 00 48 8=
3 c3 18 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74=
 08 48 89 df e8 d0 75 c8 ff 48 8b 1b b8 58 01 00 00
> RSP: 0018:ffffc90003fef560 EFLAGS: 00010206
> RAX: 0000000000000003 RBX: 0000000000000018 RCX: dffffc0000000000
> RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
> RBP: ffffc90003fef860 R08: ffff8881148d8fff R09: 0000000000000000
> R10: ffff8881148d8000 R11: ffffed102291b200 R12: 1ffff920007fdecc
> R13: 0000000000000000 R14: ffff888166b45340 R15: 0000000000001000
> FS:  00007fd77743d6c0(0000) GS:ffff8882a8f51000(0000) knlGS:0000000000000=
000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007faa8f64dc80 CR3: 000000011606a000 CR4: 00000000000006f0
> ----------------
> Code disassembly (best guess):
>    0:   e2 5a                   loop   0x5c
>    2:   ff 83 e3 08 75 5c       incl   0x5c7508e3(%rbx)
>    8:   e8 ab de 5a ff          call   0xff5adeb8
>    d:   48 8b 9c 24 68 01 00    mov    0x168(%rsp),%rbx
>   14:   00
>   15:   48 83 c3 18             add    $0x18,%rbx
>   19:   48 89 d8                mov    %rbx,%rax
>   1c:   48 c1 e8 03             shr    $0x3,%rax
>   20:   48 b9 00 00 00 00 00    movabs $0xdffffc0000000000,%rcx
>   27:   fc ff df
> * 2a:   80 3c 08 00             cmpb   $0x0,(%rax,%rcx,1) <-- trapping in=
struction
>   2e:   74 08                   je     0x38
>   30:   48 89 df                mov    %rbx,%rdi
>   33:   e8 d0 75 c8 ff          call   0xffc87608
>   38:   48 8b 1b                mov    (%rbx),%rbx
>   3b:   b8 58 01 00 00          mov    $0x158,%eax
>
>
> ***
>
> 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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>
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>
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>
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>
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>
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--=20
=E2=B2=A0=E2=B2=9F=E2=B2=93=E2=B2=99=E2=B2=8F=E2=B2=9B =E2=B2=84=E2=B2=89=
=E2=B2=B1=E2=B2=A3=E2=B2=85=E2=B2=93=E2=B2=9F=E2=B2=A5 - Pimyn Girgis
Software Engineer
Kernel Dynamic Analysis
[email protected]