syzbot


BUG: unable to handle kernel paging request in can_vma_merge_left

Status: premoderation: reported C repro on 2025/06/21 01:16
Bug presence: origin:lts
[Documentation on labels]
Reported-by: syzbot+7ef7166a40ef1a3533f7@syzkaller.appspotmail.com
First crash: 3d19h, last: 3d18h
Bug presence (2)
Date Name Commit Repro Result
2025/06/22 lts (merge base) 83b4161a63b8 C [report] BUG: unable to handle kernel paging request in can_vma_merge_left
2025/06/22 upstream (ToT) 739a6c93cc75 C Didn't crash

Sample crash report:
Code: 48 83 c4 28 c3 e8 17 1a 00 00 0f 1f 80 00 00 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd3c1c20c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 00007ffd3c1c20d0 RCX: 00007f751e2bf369
RDX: 00007f751e2be6a0 RSI: 00007ffd3c1c20d0 RDI: 0000000000000003
RBP: 0000000000000001 R08: 00007ffd3c1c1e67 R09: 00007f751e320031
R10: 0000000000000001 R11: 0000000000000246 R12: 00007f751e32a618
R13: 00007ffd3c1c22a8 R14: 0000000000000001 R15: 0000000000000001
 </TASK>
BUG: unable to handle page fault for address: fffffffffffffffc
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 72ae067 P4D 72ae067 PUD 72b0067 PMD 0 

Oops: Oops: 0000 [#1] PREEMPT SMP KASAN PTI
CPU: 1 UID: 0 PID: 296 Comm: syz-executor242 Not tainted 6.12.23-syzkaller-gd9fd901baa98 #0 f1acc3ef52b3e732a05c4f7a2560722db90bb473
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:can_vma_merge_left+0x6c/0x4c0 mm/vma.c:296
Code: ff 0f 84 2b 01 00 00 4d 8d 67 08 4c 89 e0 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 80 3c 08 00 74 08 4c 89 e7 e8 d4 28 08 00 <4d> 8b 24 24 4c 89 6d d0 49 83 c5 30 4c 89 e8 48 c1 e8 03 48 b9 00
RSP: 0018:ffffc9000120f8f8 EFLAGS: 00010246

RAX: 1fffffffffffffff RBX: ffffc9000120fa38 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffc9000120fa20
RBP: ffffc9000120f938 R08: ffff88812457e09f R09: 1ffff110248afc13
R10: dffffc0000000000 R11: ffffed10248afc14 R12: fffffffffffffffc
R13: ffffc9000120fa20 R14: 1ffff92000241f47 R15: fffffffffffffff4
FS:  00005555680f7380(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffffffffffffffc CR3: 000000011f4f6000 CR4: 00000000003526b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 vma_merge_existing_range mm/vma.c:703 [inline]
 vma_modify+0x250/0x1430 mm/vma.c:1427
 vma_modify_flags_uffd+0x15a/0x190 mm/vma.c:1508
 userfaultfd_clear_vma+0x1e8/0x260 mm/userfaultfd.c:1894
 userfaultfd_release_all+0x280/0x490 mm/userfaultfd.c:2012
 userfaultfd_release+0xe2/0x1a0 fs/userfaultfd.c:866
 __fput+0x1fb/0xa00 fs/file_table.c:431
 __fput_sync+0x4a/0x70 fs/file_table.c:516
 __do_sys_close fs/open.c:1590 [inline]
 __se_sys_close+0x17b/0x240 fs/open.c:1575
 __x64_sys_close+0x3c/0x60 fs/open.c:1575
 x64_sys_call+0x2560/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:4
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x58/0xf0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f751e2bf369
Code: 48 83 c4 28 c3 e8 17 1a 00 00 0f 1f 80 00 00 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd3c1c20c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 00007ffd3c1c20d0 RCX: 00007f751e2bf369
RDX: 00007f751e2be6a0 RSI: 00007ffd3c1c20d0 RDI: 0000000000000003
RBP: 0000000000000001 R08: 00007ffd3c1c1e67 R09: 00007f751e320031
R10: 0000000000000001 R11: 0000000000000246 R12: 00007f751e32a618
R13: 00007ffd3c1c22a8 R14: 0000000000000001 R15: 0000000000000001
 </TASK>
Modules linked in:
CR2: fffffffffffffffc
---[ end trace 0000000000000000 ]---
RIP: 0010:can_vma_merge_left+0x6c/0x4c0 mm/vma.c:296
Code: ff 0f 84 2b 01 00 00 4d 8d 67 08 4c 89 e0 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 80 3c 08 00 74 08 4c 89 e7 e8 d4 28 08 00 <4d> 8b 24 24 4c 89 6d d0 49 83 c5 30 4c 89 e8 48 c1 e8 03 48 b9 00
RSP: 0018:ffffc9000120f8f8 EFLAGS: 00010246
RAX: 1fffffffffffffff RBX: ffffc9000120fa38 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffc9000120fa20
RBP: ffffc9000120f938 R08: ffff88812457e09f R09: 1ffff110248afc13
R10: dffffc0000000000 R11: ffffed10248afc14 R12: fffffffffffffffc
R13: ffffc9000120fa20 R14: 1ffff92000241f47 R15: fffffffffffffff4
FS:  00005555680f7380(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffffffffffffffc CR3: 000000011f4f6000 CR4: 00000000003526b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	48 83 c4 28          	add    $0x28,%rsp
   4:	c3                   	ret
   5:	e8 17 1a 00 00       	call   0x1a21
   a:	0f 1f 80 00 00 00 00 	nopl   0x0(%rax)
  11:	48 89 f8             	mov    %rdi,%rax
  14:	48 89 f7             	mov    %rsi,%rdi
  17:	48 89 d6             	mov    %rdx,%rsi
  1a:	48 89 ca             	mov    %rcx,%rdx
  1d:	4d 89 c2             	mov    %r8,%r10
  20:	4d 89 c8             	mov    %r9,%r8
  23:	4c 8b 4c 24 08       	mov    0x8(%rsp),%r9
  28:	0f 05                	syscall
* 2a:	48 3d 01 f0 ff ff    	cmp    $0xfffffffffffff001,%rax <-- trapping instruction
  30:	73 01                	jae    0x33
  32:	c3                   	ret
  33:	48 c7 c1 b8 ff ff ff 	mov    $0xffffffffffffffb8,%rcx
  3a:	f7 d8                	neg    %eax
  3c:	64 89 01             	mov    %eax,%fs:(%rcx)
  3f:	48                   	rex.W

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/06/21 02:53 android16-6.12 d9fd901baa98 d6cdfb8a .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust BUG: unable to handle kernel paging request in can_vma_merge_left
2025/06/21 01:15 android16-6.12 6c1c18fcb8b7 804b3919 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust BUG: unable to handle kernel paging request in can_vma_merge_left
2025/06/21 01:15 android16-6.12 6c1c18fcb8b7 804b3919 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust BUG: unable to handle kernel paging request in can_vma_merge_left
* Struck through repros no longer work on HEAD.