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

#syz upstream


On Fri, Jul 10, 2026 at 10:52 PM syzbot ci
<[email protected]> wrote:
>
> syzbot ci has tested the following series
>
> [v2] Use generic_file_read_iter() in hugetlbfs
> https://lore.kernel.org/all/[email protected]
> * [PATCH v2 01/10] mm: Rename folio_contain_hwpoison_page() to folio_has_hwpoison_page()
> * [PATCH v2 02/10] hugetlb: Mark some function arguments as const
> * [PATCH v2 03/10] filemap: Remove checks in mapping_set_folio_order_range()
> * [PATCH v2 04/10] hugetlb: Set mapping folio order
> * [PATCH v2 05/10] memory-failure: Remove raw_hwp_list_head()
> * [PATCH v2 06/10] memory-failure: Prevent UAF in raw_hwp_page list
> * [PATCH v2 07/10] mm: Handle hugetlb correctly in is_page_hwpoison()
> * [PATCH v2 08/10] filemap: Add hwpoison handling to filemap_read()
> * [PATCH v2 09/10] filemap: Add support for authoritative mappings
> * [PATCH v2 10/10] hugetlb: replace hugetlbfs_read_iter() with generic_file_read_iter()
>
> and found the following issue:
> BUG: unable to handle kernel NULL pointer dereference in filemap_read_folio
>
> Full report is available here:
> https://ci.syzbot.org/series/35ead019-1e81-4d15-8801-8ff11d9c959b
>
> ***
>
> BUG: unable to handle kernel NULL pointer dereference in filemap_read_folio
>
> tree:      mm-new
> URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/akpm/mm.git
> base:      dc59e4fea9d83f03bad6bddf3fa2e52491777482
> 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/fedb89e4-11ba-4995-927f-a51101829a59/config
> syz repro: https://ci.syzbot.org/findings/7a0cb565-4340-4daf-8de2-06f5b1d2af93/syz_repro
>
> BUG: kernel NULL pointer dereference, address: 0000000000000000
> #PF: supervisor instruction fetch in kernel mode
> #PF: error_code(0x0010) - not-present page
> PGD 8000000117bc9067 P4D 8000000117bc9067 PUD 0
> Oops: Oops: 0010 [#1] SMP KASAN PTI
> CPU: 0 UID: 0 PID: 5840 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: 0010:0x0
> Code: Unable to access opcode bytes at 0xffffffffffffffd6.
> RSP: 0018:ffffc900035eebf8 EFLAGS: 00010293
> RAX: ffffffff82063559 RBX: 1ffff920006bdd84 RCX: ffff88810ba18000
> RDX: 0000000000000000 RSI: ffffea0000948000 RDI: ffff88810139d200
> RBP: ffffc900035eecb0 R08: ffffea0000948007 R09: 1ffffd4000129000
> R10: dffffc0000000000 R11: 0000000000000000 R12: 0000000000000000
> R13: 1ffffd4000129000 R14: ffffea0000948000 R15: 1ffffd4000129001
> FS:  00007f2e39ef46c0(0000) GS:ffff88818dc11000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: ffffffffffffffd6 CR3: 000000011578a000 CR4: 00000000000006f0
> Call Trace:
>  <TASK>
>  filemap_read_folio+0x12c/0x3a0 mm/filemap.c:2512
>  filemap_create_folio mm/filemap.c:2650 [inline]
>  filemap_get_pages+0xe9a/0x21e0 mm/filemap.c:2714
>  filemap_read+0x428/0x1700 mm/filemap.c:2841
>  __kernel_read+0x4ca/0x960 fs/read_write.c:532
>  integrity_kernel_read+0x89/0xd0 security/integrity/iint.c:28
>  ima_calc_file_hash_tfm security/integrity/ima/ima_crypto.c:222 [inline]
>  ima_calc_file_hash+0x451/0x890 security/integrity/ima/ima_crypto.c:280
>  ima_collect_measurement+0x51b/0xa00 security/integrity/ima/ima_api.c:300
>  process_measurement+0x1272/0x1c10 security/integrity/ima/ima_main.c:425
>  ima_file_mmap+0x1b0/0x200 security/integrity/ima/ima_main.c:523
>  security_mmap_file+0x773/0xa20 security/security.c:2581
>  vm_mmap_pgoff+0x134/0x4e0 mm/util.c:575
>  ksys_mmap_pgoff+0x57d/0x760 mm/mmap.c:606
>  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: 0033:0x7f2e38f9ce59
> 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:00007f2e39ef4028 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
> RAX: ffffffffffffffda RBX: 00007f2e39215fa0 RCX: 00007f2e38f9ce59
> RDX: 0000000000000007 RSI: 0000000000003000 RDI: 0000200000000000
> RBP: 00007f2e39032e6f R08: ffffffffffffffff R09: 0000000000000000
> R10: 0000000000040033 R11: 0000000000000246 R12: 0000000000000000
> R13: 00007f2e39216038 R14: 00007f2e39215fa0 R15: 00007ffe3450a298
>  </TASK>
> Modules linked in:
> CR2: 0000000000000000
> ---[ end trace 0000000000000000 ]---
> RIP: 0010:0x0
> Code: Unable to access opcode bytes at 0xffffffffffffffd6.
> RSP: 0018:ffffc900035eebf8 EFLAGS: 00010293
> RAX: ffffffff82063559 RBX: 1ffff920006bdd84 RCX: ffff88810ba18000
> RDX: 0000000000000000 RSI: ffffea0000948000 RDI: ffff88810139d200
> RBP: ffffc900035eecb0 R08: ffffea0000948007 R09: 1ffffd4000129000
> R10: dffffc0000000000 R11: 0000000000000000 R12: 0000000000000000
> R13: 1ffffd4000129000 R14: ffffea0000948000 R15: 1ffffd4000129001
> FS:  00007f2e39ef46c0(0000) GS:ffff88818dc11000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: ffffffffffffffd6 CR3: 000000011578a000 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]
>
> ---
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-- 
Ⲡⲟⲓⲙⲏⲛ Ⲅⲉⲱⲣⲅⲓⲟⲥ - Pimyn Girgis
Software Engineer
Kernel Dynamic Analysis
[email protected]