Re: [moderation/CI] Re: Use generic_file_read_iter() in hugetlbfs

Pimyn Girgis <[email protected]> Sat, 25 Jul 2026 07:02:36 +0200
Newsgroups	dev.linux.lists.syzbot
Message-ID	<CAJWNTGyP2dj56Z-rNRJTpA-7ecnnx9OHMw1UeQck_e1g9hbh_w@mail.gmail.com>
#syz upstream


On Sat, Jul 25, 2026 at 1:35 AM syzbot ci
<[email protected]> wrote:
>
> syzbot ci has tested the following series
>
> [v4] Use generic_file_read_iter() in hugetlbfs
> https://lore.kernel.org/all/[email protected]
> * [PATCH v4 01/14] memory-failure: Fix hardware poison check in unpoison_memory() again
> * [PATCH v4 02/14] memory-failure: Test the page is hwpoison before taking the mutex
> * [PATCH v4 03/14] mm: Rename folio_contain_hwpoison_page() to folio_has_hwpoison_page()
> * [PATCH v4 04/14] hugetlb: Mark some function arguments as const
> * [PATCH v4 05/14] guest_memfd: Use folio_has_hwpoisoned_page()
> * [PATCH v4 06/14] memory-failure: Remove raw_hwp_list_head()
> * [PATCH v4 07/14] hugetlb: Use the has_hwpoisoned flag
> * [PATCH v4 08/14] mm: Remove locking mf_mutex in is_raw_hwpoison_page_in_hugepage()
> * [PATCH v4 09/14] mm: Check individual hugetlb pages for poison
> * [PATCH v4 10/14] filemap: Add hwpoison handling to filemap_read()
> * [PATCH v4 11/14] filemap: Remove checks in mapping_set_folio_order_range()
> * [PATCH v4 12/14] hugetlb: Set mapping folio order
> * [PATCH v4 13/14] filemap: Add support for authoritative mappings
> * [PATCH v4 14/14] hugetlb: replace hugetlbfs_read_iter() with generic_file_read_iter()
>
> and found the following issues:
> * WARNING in bio_add_page
> * general protection fault in create_empty_buffers
>
> Full report is available here:
> https://ci.syzbot.org/series/4b3a4f52-06f4-4a41-872f-dde0771be8ef
>
> ***
>
> WARNING in bio_add_page
>
> tree:      mm-new
> URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/akpm/mm.git
> base:      1590cf0329716306e948a8fc29f1d3ee87d3989f
> arch:      amd64
> compiler:  Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
> config:    https://ci.syzbot.org/builds/bb071828-9749-428c-a78c-fc39b0b5caf2/config
> syz repro: https://ci.syzbot.org/findings/38d53450-b153-4f47-8474-be250791ea91/syz_repro
>
> ------------[ cut here ]------------
> len == 0
> WARNING: block/bio.c:1052 at bio_add_page+0x516/0x700 block/bio.c:1052, CPU#0: udevd/5630
> Modules linked in:
> CPU: 0 UID: 0 PID: 5630 Comm: udevd 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:bio_add_page+0x516/0x700 block/bio.c:1052
> Code: 31 ed 44 89 e8 48 83 c4 50 5b 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc e8 86 5e 17 fd 90 0f 0b 90 eb db e8 7b 5e 17 fd 90 <0f> 0b 90 eb d0 e8 70 5e 17 fd 90 0f 0b 90 e9 76 fe ff ff e8 62 5e
> RSP: 0018:ffffc9000487f0f8 EFLAGS: 00010293
> RAX: ffffffff84af2445 RBX: 0000000000000000 RCX: ffff8881108d0000
> RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
> RBP: 1ffff110228761e2 R08: ffff8881143b0f7f R09: 1ffff110228761ef
> R10: dffffc0000000000 R11: ffffed10228761f0 R12: ffff8881143b0f14
> R13: 0000000000000000 R14: dffffc0000000000 R15: 0000000000000000
> FS:  00007faeac7ccc80(0000) GS:ffff88818d945000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000295e815ae000 CR3: 0000000114e0e000 CR4: 00000000000006f0
> Call Trace:
>  <TASK>
>  bio_add_folio+0x64/0x90 block/bio.c:1107
>  do_mpage_readpage+0xd8c/0x1b40 fs/mpage.c:294
>  mpage_readahead+0x3e7/0x800 fs/mpage.c:370
>  read_pages+0x193/0x5a0 mm/readahead.c:174
>  page_cache_ra_unbounded+0x679/0x8f0 mm/readahead.c:315
>  do_page_cache_ra mm/readahead.c:348 [inline]
>  force_page_cache_ra+0x26c/0x2e0 mm/readahead.c:378
>  filemap_get_pages+0x4d9/0x1ef0 mm/filemap.c:2708
>  filemap_read+0x422/0x1630 mm/filemap.c:2841
>  blkdev_read_iter+0x2f1/0x420 block/fops.c:830
>  new_sync_read fs/read_write.c:493 [inline]
>  vfs_read+0x595/0xa80 fs/read_write.c:574
>  ksys_read+0x150/0x270 fs/read_write.c:716
>  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: 0033:0x7faeac316b6a
> Code: 00 3d 00 00 41 00 75 0d 50 48 8d 3d 2d 08 0a 00 e8 ea 7d 01 00 31 c0 e9 07 ff ff ff 64 8b 04 25 18 00 00 00 85 c0 75 1b 0f 05 <48> 3d 00 f0 ff ff 76 6c 48 8b 15 8f a2 0d 00 f7 d8 64 89 02 48 83
> RSP: 002b:00007ffd8d811da8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
> RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007faeac316b6a
> RDX: 0000000000000400 RSI: 0000557e6b670e18 RDI: 0000000000000009
> RBP: 0000000000000400 R08: 0000557e6b670df0 R09: 0000000000000008
> R10: 0000000000000051 R11: 0000000000000246 R12: 0000557e6b670df0
> R13: 0000557e6b670e08 R14: 0000557e6b66e128 R15: 0000557e6b66e0d0
>  </TASK>
>
>
> ***
>
> general protection fault in create_empty_buffers
>
> tree:      mm-new
> URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/akpm/mm.git
> base:      1590cf0329716306e948a8fc29f1d3ee87d3989f
> arch:      amd64
> compiler:  Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
> config:    https://ci.syzbot.org/builds/bb071828-9749-428c-a78c-fc39b0b5caf2/config
> syz repro: https://ci.syzbot.org/findings/2406d176-ea76-40a8-b6bc-41d3e6326388/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: 5932 Comm: udevd 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:create_empty_buffers+0x48/0x520 fs/buffer.c:1672
> Code: 00 00 00 00 fc ff df e8 96 dc 69 ff 48 89 df 4c 89 e6 ba 40 8c 40 00 e8 e6 bc ff ff 49 89 c4 48 89 04 24 4c 89 e0 48 c1 e8 03 <42> 80 3c 30 00 74 08 4c 89 e7 e8 09 bc d7 ff 4d 09 3c 24 49 83 c4
> RSP: 0018:ffffc900034bf570 EFLAGS: 00010246
> RAX: 0000000000000000 RBX: ffffea0005ceb100 RCX: 0000000000000046
> RDX: 0000000000000002 RSI: ffffffff8e4b7f70 RDI: ffff888172cdbb80
> RBP: ffffc900034bf6f0 R08: ffffffff825c6656 R09: 0000000000000000
> R10: 0000000000000000 R11: ffffffff8eb5a120 R12: 0000000000000000
> R13: 1ffffd4000b9d620 R14: dffffc0000000000 R15: 0000000000000000
> FS:  00007fd3c0fc7c80(0000) GS:ffff8882a8f45000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00005567a5ebae48 CR3: 000000017395c000 CR4: 00000000000006f0
> Call Trace:
>  <TASK>
>  block_read_full_folio+0x116/0x810 fs/buffer.c:2381
>  filemap_read_folio+0x12c/0x3a0 mm/filemap.c:2512
>  filemap_update_page mm/filemap.c:2599 [inline]
>  filemap_get_pages+0x1742/0x1ef0 mm/filemap.c:2731
>  filemap_read+0x422/0x1630 mm/filemap.c:2841
>  blkdev_read_iter+0x2f1/0x420 block/fops.c:830
>  new_sync_read fs/read_write.c:493 [inline]
>  vfs_read+0x595/0xa80 fs/read_write.c:574
>  ksys_read+0x150/0x270 fs/read_write.c:716
>  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: 0033:0x7fd3c0b16b6a
> Code: 00 3d 00 00 41 00 75 0d 50 48 8d 3d 2d 08 0a 00 e8 ea 7d 01 00 31 c0 e9 07 ff ff ff 64 8b 04 25 18 00 00 00 85 c0 75 1b 0f 05 <48> 3d 00 f0 ff ff 76 6c 48 8b 15 8f a2 0d 00 f7 d8 64 89 02 48 83
> RSP: 002b:00007ffcab174708 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
> RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fd3c0b16b6a
> RDX: 0000000000000400 RSI: 000055c883b6c638 RDI: 0000000000000009
> RBP: 0000000000000400 R08: 000055c883b6c610 R09: 0000000000000008
> R10: 0000000000000051 R11: 0000000000000246 R12: 000055c883b6c610
> R13: 000055c883b6c628 R14: 000055c883b60b48 R15: 000055c883b60af0
>  </TASK>
> Modules linked in:
> ---[ end trace 0000000000000000 ]---
> RIP: 0010:create_empty_buffers+0x48/0x520 fs/buffer.c:1672
> Code: 00 00 00 00 fc ff df e8 96 dc 69 ff 48 89 df 4c 89 e6 ba 40 8c 40 00 e8 e6 bc ff ff 49 89 c4 48 89 04 24 4c 89 e0 48 c1 e8 03 <42> 80 3c 30 00 74 08 4c 89 e7 e8 09 bc d7 ff 4d 09 3c 24 49 83 c4
> RSP: 0018:ffffc900034bf570 EFLAGS: 00010246
>
> RAX: 0000000000000000 RBX: ffffea0005ceb100 RCX: 0000000000000046
> RDX: 0000000000000002 RSI: ffffffff8e4b7f70 RDI: ffff888172cdbb80
> RBP: ffffc900034bf6f0 R08: ffffffff825c6656 R09: 0000000000000000
> R10: 0000000000000000 R11: ffffffff8eb5a120 R12: 0000000000000000
> R13: 1ffffd4000b9d620 R14: dffffc0000000000 R15: 0000000000000000
> FS:  00007fd3c0fc7c80(0000) GS:ffff8882a8f45000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000001b30763fff CR3: 000000017395c000 CR4: 00000000000006f0
> ----------------
> Code disassembly (best guess), 6 bytes skipped:
>    0:   df e8                   fucomip %st(0),%st
>    2:   96                      xchg   %eax,%esi
>    3:   dc 69 ff                fsubrl -0x1(%rcx)
>    6:   48 89 df                mov    %rbx,%rdi
>    9:   4c 89 e6                mov    %r12,%rsi
>    c:   ba 40 8c 40 00          mov    $0x408c40,%edx
>   11:   e8 e6 bc ff ff          call   0xffffbcfc
>   16:   49 89 c4                mov    %rax,%r12
>   19:   48 89 04 24             mov    %rax,(%rsp)
>   1d:   4c 89 e0                mov    %r12,%rax
>   20:   48 c1 e8 03             shr    $0x3,%rax
> * 24:   42 80 3c 30 00          cmpb   $0x0,(%rax,%r14,1) <-- trapping instruction
>   29:   74 08                   je     0x33
>   2b:   4c 89 e7                mov    %r12,%rdi
>   2e:   e8 09 bc d7 ff          call   0xffd7bc3c
>   33:   4d 09 3c 24             or     %r15,(%r12)
>   37:   49                      rex.WB
>   38:   83                      .byte 0x83
>   39:   c4                      .byte 0xc4
>
>
> ***
>
> 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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-- 
Ⲡⲟⲓⲙⲏⲛ Ⲅⲉⲱⲣⲅⲓⲟⲥ - Pimyn Girgis
Software Engineer
Kernel Dynamic Analysis
[email protected]