syzbot


general protection fault in mpage_readahead

Status: moderation: reported on 2025/10/02 03:39
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+31c428684be9035d5108@syzkaller.appspotmail.com
First crash: 88d, last: 22d

Sample crash report:
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
CPU: 0 UID: 0 PID: 9262 Comm: syz.7.733 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:const_folio_flags include/linux/page-flags.h:351 [inline]
RIP: 0010:folio_test_locked include/linux/page-flags.h:551 [inline]
RIP: 0010:__readahead_folio include/linux/pagemap.h:1428 [inline]
RIP: 0010:readahead_folio include/linux/pagemap.h:1444 [inline]
RIP: 0010:mpage_readahead+0x1bf/0x790 fs/mpage.c:367
Code: 89 e7 e8 84 70 db ff 49 8b 3c 24 48 83 c7 08 4c 89 fe e8 64 a0 f9 08 49 89 c7 48 8d 58 08 48 89 d8 48 c1 e8 03 48 89 44 24 38 <42> 80 3c 28 00 74 08 48 89 df e8 52 70 db ff 4c 8b 33 4c 89 f6 48
RSP: 0018:ffffc900033f7160 EFLAGS: 00010212
RAX: 0000000000000001 RBX: 0000000000000008 RCX: e342025c6ce47a00
RDX: 0000000000000001 RSI: ffffffff8d94db09 RDI: ffff88801e799e80
RBP: ffffc900033f7350 R08: ffff88801e799e80 R09: 0000000000000002
R10: 0000000000000406 R11: 0000000000000002 R12: ffffc900033f75c8
R13: dffffc0000000000 R14: 0000000000000020 R15: 0000000000000000
FS:  00007f58c75926c0(0000) GS:ffff8881260c0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000000 CR3: 0000000057c81000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 read_pages+0x17a/0x580 mm/readahead.c:163
 page_cache_ra_unbounded+0x74e/0x990 mm/readahead.c:302
 do_sync_mmap_readahead+0x25e/0x7a0 mm/filemap.c:-1
 filemap_fault+0x6be/0x1290 mm/filemap.c:3534
 __do_fault+0x138/0x390 mm/memory.c:5281
 do_read_fault mm/memory.c:5716 [inline]
 do_fault mm/memory.c:5850 [inline]
 do_pte_missing mm/memory.c:4362 [inline]
 handle_pte_fault mm/memory.c:6234 [inline]
 __handle_mm_fault+0x3610/0x5420 mm/memory.c:6366
 handle_mm_fault+0x40a/0x8e0 mm/memory.c:6535
 faultin_page mm/gup.c:1126 [inline]
 __get_user_pages+0x165c/0x2a00 mm/gup.c:1428
 populate_vma_page_range+0x29f/0x3a0 mm/gup.c:1860
 __mm_populate+0x24c/0x380 mm/gup.c:1963
 mm_populate include/linux/mm.h:3455 [inline]
 vm_mmap_pgoff+0x387/0x4d0 mm/util.c:586
 ksys_mmap_pgoff+0x51f/0x760 mm/mmap.c:604
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f58c678f749
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:00007f58c7592038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007f58c69e5fa0 RCX: 00007f58c678f749
RDX: 0000000001000002 RSI: 0000000000b36000 RDI: 0000200000000000
RBP: 00007f58c6813f91 R08: 0000000000000006 R09: 000000002c93a000
R10: 0000000000028011 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f58c69e6038 R14: 00007f58c69e5fa0 R15: 00007fffd92ea678
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:const_folio_flags include/linux/page-flags.h:351 [inline]
RIP: 0010:folio_test_locked include/linux/page-flags.h:551 [inline]
RIP: 0010:__readahead_folio include/linux/pagemap.h:1428 [inline]
RIP: 0010:readahead_folio include/linux/pagemap.h:1444 [inline]
RIP: 0010:mpage_readahead+0x1bf/0x790 fs/mpage.c:367
Code: 89 e7 e8 84 70 db ff 49 8b 3c 24 48 83 c7 08 4c 89 fe e8 64 a0 f9 08 49 89 c7 48 8d 58 08 48 89 d8 48 c1 e8 03 48 89 44 24 38 <42> 80 3c 28 00 74 08 48 89 df e8 52 70 db ff 4c 8b 33 4c 89 f6 48
RSP: 0018:ffffc900033f7160 EFLAGS: 00010212
RAX: 0000000000000001 RBX: 0000000000000008 RCX: e342025c6ce47a00
RDX: 0000000000000001 RSI: ffffffff8d94db09 RDI: ffff88801e799e80
RBP: ffffc900033f7350 R08: ffff88801e799e80 R09: 0000000000000002
R10: 0000000000000406 R11: 0000000000000002 R12: ffffc900033f75c8
R13: dffffc0000000000 R14: 0000000000000020 R15: 0000000000000000
FS:  00007f58c75926c0(0000) GS:ffff8881260c0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f68d2b19000 CR3: 0000000057c81000 CR4: 0000000000350ef0
----------------
Code disassembly (best guess):
   0:	89 e7                	mov    %esp,%edi
   2:	e8 84 70 db ff       	call   0xffdb708b
   7:	49 8b 3c 24          	mov    (%r12),%rdi
   b:	48 83 c7 08          	add    $0x8,%rdi
   f:	4c 89 fe             	mov    %r15,%rsi
  12:	e8 64 a0 f9 08       	call   0x8f9a07b
  17:	49 89 c7             	mov    %rax,%r15
  1a:	48 8d 58 08          	lea    0x8(%rax),%rbx
  1e:	48 89 d8             	mov    %rbx,%rax
  21:	48 c1 e8 03          	shr    $0x3,%rax
  25:	48 89 44 24 38       	mov    %rax,0x38(%rsp)
* 2a:	42 80 3c 28 00       	cmpb   $0x0,(%rax,%r13,1) <-- trapping instruction
  2f:	74 08                	je     0x39
  31:	48 89 df             	mov    %rbx,%rdi
  34:	e8 52 70 db ff       	call   0xffdb708b
  39:	4c 8b 33             	mov    (%rbx),%r14
  3c:	4c 89 f6             	mov    %r14,%rsi
  3f:	48                   	rex.W

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/12/03 15:42 upstream 619f4edc8d4f d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root general protection fault in mpage_readahead
2025/10/21 21:33 linux-next fe45352cd106 9832ed61 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root general protection fault in mpage_readahead
2025/09/28 03:37 linux-next 262858079afd 001c9061 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root general protection fault in mpage_readahead
* Struck through repros no longer work on HEAD.