syzbot


BUG: unable to handle kernel paging request in page_cache_ra_unbounded

Status: moderation: reported on 2025/07/28 08:58
Subsystems: mm fs
[Documentation on labels]
Reported-by: syzbot+4d1b2237d7fe0258f026@syzkaller.appspotmail.com
First crash: 6d08h, last: 6d08h

Sample crash report:
BUG: unable to handle page fault for address: fffff521017aed95
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 23ffed067 P4D 23ffed067 PUD 0 
Oops: Oops: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 18941 Comm: syz.7.3156 Not tainted 6.16.0-rc7-syzkaller-00018-g01a412d06bc5 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:page_cache_ra_unbounded+0x3b2/0x7d0 mm/readahead.c:287
Code: 89 e0 48 c1 e8 03 42 80 3c 38 00 0f 85 9c 03 00 00 48 8d 7b 29 4d 8b 24 24 48 89 f8 48 89 fa 48 c1 e8 03 49 c1 ec 09 83 e2 07 <42> 0f b6 04 38 41 83 e4 01 38 d0 7f 08 84 c0 0f 85 64 03 00 00 48
RSP: 0018:ffffc9000bd76a38 EFLAGS: 00010202
RAX: 1ffff920017aed96 RBX: ffffc9000bd76c88 RCX: ffffffff81f4b2f7
RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffffc9000bd76cb1
RBP: 0000000000000000 R08: 0000000000000000 R09: fffff94000253ce0
R10: ffffea000129e707 R11: 0000000000000001 R12: 00007ff800000000
R13: 0000000000000001 R14: ffff8880543b1a78 R15: dffffc00ffffffff
FS:  00007f362f0246c0(0000) GS:ffff888124727000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffff521017aed95 CR3: 0000000062c3f000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 do_page_cache_ra mm/readahead.c:327 [inline]
 page_cache_ra_order+0x9c8/0xd00 mm/readahead.c:532
 page_cache_sync_ra+0x4b4/0x9c0 mm/readahead.c:621
 filemap_get_pages+0xb62/0x1c20 mm/filemap.c:2602
 filemap_read+0x3d2/0xe40 mm/filemap.c:2711
 generic_file_read_iter+0x344/0x450 mm/filemap.c:2903
 ntfs_file_read_iter+0x10e/0x1c0 fs/ntfs3/file.c:842
 __kernel_read+0x3f3/0xb60 fs/read_write.c:530
 integrity_kernel_read+0x7e/0xb0 security/integrity/iint.c:28
 ima_calc_file_hash_tfm+0x259/0x350 security/integrity/ima/ima_crypto.c:480
 ima_calc_file_shash security/integrity/ima/ima_crypto.c:511 [inline]
 ima_calc_file_hash+0x1ba/0x490 security/integrity/ima/ima_crypto.c:568
 ima_collect_measurement+0x897/0xa40 security/integrity/ima/ima_api.c:293
 process_measurement+0x11fa/0x23e0 security/integrity/ima/ima_main.c:385
 ima_file_check+0xc5/0x110 security/integrity/ima/ima_main.c:613
 security_file_post_open+0x8e/0x210 security/security.c:3130
 do_open fs/namei.c:3898 [inline]
 path_openat+0x1404/0x2cb0 fs/namei.c:4055
 do_filp_open+0x20b/0x470 fs/namei.c:4082
 do_sys_openat2+0x11b/0x1d0 fs/open.c:1437
 do_sys_open fs/open.c:1452 [inline]
 __do_sys_openat fs/open.c:1468 [inline]
 __se_sys_openat fs/open.c:1463 [inline]
 __x64_sys_openat+0x174/0x210 fs/open.c:1463
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f362e18e9a9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f362f024038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f362e3b6080 RCX: 00007f362e18e9a9
RDX: 0000000000143042 RSI: 0000200000000d80 RDI: ffffffffffffff9c
RBP: 00007f362e210d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007f362e3b6080 R15: 00007fffdf8e1d78
 </TASK>
Modules linked in:
CR2: fffff521017aed95
---[ end trace 0000000000000000 ]---
RIP: 0010:page_cache_ra_unbounded+0x3b2/0x7d0 mm/readahead.c:287
Code: 89 e0 48 c1 e8 03 42 80 3c 38 00 0f 85 9c 03 00 00 48 8d 7b 29 4d 8b 24 24 48 89 f8 48 89 fa 48 c1 e8 03 49 c1 ec 09 83 e2 07 <42> 0f b6 04 38 41 83 e4 01 38 d0 7f 08 84 c0 0f 85 64 03 00 00 48
RSP: 0018:ffffc9000bd76a38 EFLAGS: 00010202
RAX: 1ffff920017aed96 RBX: ffffc9000bd76c88 RCX: ffffffff81f4b2f7
RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffffc9000bd76cb1
RBP: 0000000000000000 R08: 0000000000000000 R09: fffff94000253ce0
R10: ffffea000129e707 R11: 0000000000000001 R12: 00007ff800000000
R13: 0000000000000001 R14: ffff8880543b1a78 R15: dffffc00ffffffff
FS:  00007f362f0246c0(0000) GS:ffff888124727000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffff521017aed95 CR3: 0000000062c3f000 CR4: 0000000000350ef0
----------------
Code disassembly (best guess):
   0:	89 e0                	mov    %esp,%eax
   2:	48 c1 e8 03          	shr    $0x3,%rax
   6:	42 80 3c 38 00       	cmpb   $0x0,(%rax,%r15,1)
   b:	0f 85 9c 03 00 00    	jne    0x3ad
  11:	48 8d 7b 29          	lea    0x29(%rbx),%rdi
  15:	4d 8b 24 24          	mov    (%r12),%r12
  19:	48 89 f8             	mov    %rdi,%rax
  1c:	48 89 fa             	mov    %rdi,%rdx
  1f:	48 c1 e8 03          	shr    $0x3,%rax
  23:	49 c1 ec 09          	shr    $0x9,%r12
  27:	83 e2 07             	and    $0x7,%edx
* 2a:	42 0f b6 04 38       	movzbl (%rax,%r15,1),%eax <-- trapping instruction
  2f:	41 83 e4 01          	and    $0x1,%r12d
  33:	38 d0                	cmp    %dl,%al
  35:	7f 08                	jg     0x3f
  37:	84 c0                	test   %al,%al
  39:	0f 85 64 03 00 00    	jne    0x3a3
  3f:	48                   	rex.W

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/07/24 08:48 upstream 01a412d06bc5 0c1d6ded .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root BUG: unable to handle kernel paging request in page_cache_ra_unbounded
* Struck through repros no longer work on HEAD.