syzbot


general protection fault in deadline_write1_next_rq_show

Status: moderation: reported on 2026/06/12 04:03
Subsystems: block
Labels: prio:normal
[Documentation on labels]
Reported-by: syzbot+5d2df22762d003bd81cd@syzkaller.appspotmail.com
First crash: 5d22h, last: 5d22h
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision Error
49157a5a-3eee-40c9-964b-6d6f466bc7b2 assessment-security DenialOfService: ✅ Exploitable: ✅ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ general protection fault in deadline_write1_next_rq_show 2026/06/09 13:03 2026/06/09 13:03 2026/06/09 13:46 c36c07f6c1f2230a36374cbd22235f635e8f9284

Sample crash report:
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000002: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017]
CPU: 0 UID: 0 PID: 7102 Comm: syz.3.245 Tainted: G     U              syzkaller #0 PREEMPT(full) 
Tainted: [U]=USER
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:deadline_write1_next_rq_show+0x57/0x1e0 block/mq-deadline.c:855
Code: 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 8f 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 8b 5b 08 48 8d 7b 10 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 62 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 8b
RSP: 0018:ffffc9000438fa18 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffc900055c9000
RDX: 0000000000000002 RSI: ffffffff84e1e25f RDI: 0000000000000010
RBP: 0000000000000001 R08: 0000000000000007 R09: fffffffffffff000
R10: 0000000000000001 R11: 0000000000000000 R12: dffffc0000000000
R13: 0000000000000000 R14: ffff8880269cd800 R15: ffff888021f70498
FS:  00007f93e1b196c0(0000) GS:ffff88812438e000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2d21eff8 CR3: 0000000078f0a000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 traverse.part.0.constprop.0+0x107/0x650 fs/seq_file.c:112
 traverse fs/seq_file.c:99 [inline]
 seq_read_iter+0x93f/0x1270 fs/seq_file.c:196
 seq_read+0x33b/0x4c0 fs/seq_file.c:163
 full_proxy_read+0x135/0x1a0 fs/debugfs/file.c:378
 vfs_read+0x1e4/0xb30 fs/read_write.c:572
 ksys_pread64 fs/read_write.c:765 [inline]
 __do_sys_pread64 fs/read_write.c:773 [inline]
 __se_sys_pread64 fs/read_write.c:770 [inline]
 __x64_sys_pread64+0x1eb/0x250 fs/read_write.c:770
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x840 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f93e0b9ce59
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:00007f93e1b19028 EFLAGS: 00000246 ORIG_RAX: 0000000000000011
RAX: ffffffffffffffda RBX: 00007f93e0e15fa0 RCX: 00007f93e0b9ce59
RDX: 0000000000000007 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007f93e0c32d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000100 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f93e0e16038 R14: 00007f93e0e15fa0 R15: 00007fffa2b1bed8
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:deadline_write1_next_rq_show+0x57/0x1e0 block/mq-deadline.c:855
Code: 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 8f 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 8b 5b 08 48 8d 7b 10 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 62 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 8b
RSP: 0018:ffffc9000438fa18 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffc900055c9000
RDX: 0000000000000002 RSI: ffffffff84e1e25f RDI: 0000000000000010
RBP: 0000000000000001 R08: 0000000000000007 R09: fffffffffffff000
R10: 0000000000000001 R11: 0000000000000000 R12: dffffc0000000000
R13: 0000000000000000 R14: ffff8880269cd800 R15: ffff888021f70498
FS:  00007f93e1b196c0(0000) GS:ffff88812448e000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f93e0bea540 CR3: 0000000078f0a000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
   0:	48 89 fa             	mov    %rdi,%rdx
   3:	48 c1 ea 03          	shr    $0x3,%rdx
   7:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1)
   b:	0f 85 8f 01 00 00    	jne    0x1a0
  11:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  18:	fc ff df
  1b:	48 8b 5b 08          	mov    0x8(%rbx),%rbx
  1f:	48 8d 7b 10          	lea    0x10(%rbx),%rdi
  23:	48 89 fa             	mov    %rdi,%rdx
  26:	48 c1 ea 03          	shr    $0x3,%rdx
* 2a:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1) <-- trapping instruction
  2e:	0f 85 62 01 00 00    	jne    0x196
  34:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  3b:	fc ff df
  3e:	48                   	rex.W
  3f:	8b                   	.byte 0x8b

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/06/08 04:01 upstream 33d8d8ec31b5 cc095639 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto general protection fault in deadline_write1_next_rq_show
* Struck through repros no longer work on HEAD.