general protection fault in detach_timer (3)

Status: upstream: reported C repro on 2026/07/31 17:15
Subsystems: edac
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+edc6b57cbed1fb72d0f9@syzkaller.appspotmail.com
First crash: 16d, last: 4d18h
Cause bisection: failed (error log, bisect log)
  
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision
026cb556 assessment-security DenialOfService: ✅ Exploitable: ✅ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ✅ VMHostTrigger: ❌ general protection fault in detach_timer (3) 2026/07/31 01:49 2026/07/31 01:49 2026/07/31 01:57 aaffb173
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [edac?] general protection fault in detach_timer (3) 0 (1) 2026/07/31 17:15
Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream general protection fault in detach_timer (2) kernel 22 16 168d 176d 0/29 auto-obsoleted due to no activity on 2026/05/09 18:57
upstream general protection fault in detach_timer mm tomoyo batman 22 4 1198d 1202d 0/29 auto-obsoleted due to no activity on 2023/08/03 11:53
linux-5.15 KASAN: use-after-free Write in detach_timer origin:lts-only 22 syz, C error 2 213d 247d 0/3 upstream: reported C repro on 2025/12/11 21:59
Last patch testing requests (1)
Created Duration User Patch Repo Result
2026/08/13 05:17 38m tao1.yu@intel.com https://github.com/yutao-intel/linux.git fix-edac report job log log

Sample crash report:
smpboot: CPU 1 is now offline
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 0 UID: 0 PID: 5673 Comm: syz-executor341 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:__hlist_del include/linux/list.h:1029 [inline]
RIP: 0010:detach_timer+0xf9/0x2d0 kernel/time/timer.c:891
Code: 24 08 49 83 c5 08 4d 89 ee 49 c1 ee 03 4c 89 e5 43 80 3c 26 00 74 08 4c 89 ef e8 f2 47 7d 00 4d 8b 65 00 4c 89 e0 48 c1 e8 03 <80> 3c 28 00 74 08 4c 89 e7 e8 c9 48 7d 00 4d 89 3c 24 4d 85 ff 74
RSP: 0018:ffffc900046378b0 EFLAGS: 00010046
RAX: 0000000000000000 RBX: 1ffff110170e4694 RCX: ffff88803856be00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: dffffc0000000000 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: fffffbfff1f5e987 R12: 0000000000000000
R13: ffff8880b87234a8 R14: 1ffff110170e4695 R15: dead000000000122
FS:  00007f9df5c376c0(0000) GS:ffff888125c46000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffe09c7a83c CR3: 000000001147e000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 migrate_timer_list kernel/time/timer.c:2493 [inline]
 timers_dead_cpu+0x32e/0x560 kernel/time/timer.c:2541
 cpuhp_invoke_callback+0x434/0x810 kernel/cpu.c:194
 __cpuhp_invoke_callback_range kernel/cpu.c:972 [inline]
 cpuhp_invoke_callback_range kernel/cpu.c:996 [inline]
 cpuhp_down_callbacks kernel/cpu.c:1386 [inline]
 _cpu_down+0x343/0x840 kernel/cpu.c:1457
 cpu_down_maps_locked kernel/cpu.c:1483 [inline]
 cpu_down kernel/cpu.c:1491 [inline]
 cpu_device_down+0x82/0xc0 kernel/cpu.c:1508
 device_offline+0x2d2/0x3c0 drivers/base/core.c:4279
 online_store+0x123/0x1a0 drivers/base/core.c:2879
 kernfs_fop_write_iter+0x3a5/0x540 fs/kernfs/file.c:345
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x61e/0xbb0 fs/read_write.c:687
 ksys_write+0x156/0x270 fs/read_write.c:739
 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: 0033:0x7f9df5c5f909
Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 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 d0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f9df5c371d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f9df5d11b48 RCX: 00007f9df5c5f909
RDX: 0000000000000002 RSI: 0000200000000180 RDI: 0000000000000003
RBP: 00007f9df5d11b40 R08: 35203a6b63617473 R09: 35203a6b63617473
R10: 35203a6b63617473 R11: 0000000000000246 R12: 00007f9df5cde4d4
R13: 0000200000000700 R14: 0000200000000180 R15: 00002000000001a0
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__hlist_del include/linux/list.h:1029 [inline]
RIP: 0010:detach_timer+0xf9/0x2d0 kernel/time/timer.c:891
Code: 24 08 49 83 c5 08 4d 89 ee 49 c1 ee 03 4c 89 e5 43 80 3c 26 00 74 08 4c 89 ef e8 f2 47 7d 00 4d 8b 65 00 4c 89 e0 48 c1 e8 03 <80> 3c 28 00 74 08 4c 89 e7 e8 c9 48 7d 00 4d 89 3c 24 4d 85 ff 74
RSP: 0018:ffffc900046378b0 EFLAGS: 00010046
RAX: 0000000000000000 RBX: 1ffff110170e4694 RCX: ffff88803856be00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: dffffc0000000000 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: fffffbfff1f5e987 R12: 0000000000000000
R13: ffff8880b87234a8 R14: 1ffff110170e4695 R15: dead000000000122
FS:  00007f9df5c376c0(0000) GS:ffff888125c46000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffe09c7a83c CR3: 000000001147e000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
   0:	24 08                	and    $0x8,%al
   2:	49 83 c5 08          	add    $0x8,%r13
   6:	4d 89 ee             	mov    %r13,%r14
   9:	49 c1 ee 03          	shr    $0x3,%r14
   d:	4c 89 e5             	mov    %r12,%rbp
  10:	43 80 3c 26 00       	cmpb   $0x0,(%r14,%r12,1)
  15:	74 08                	je     0x1f
  17:	4c 89 ef             	mov    %r13,%rdi
  1a:	e8 f2 47 7d 00       	call   0x7d4811
  1f:	4d 8b 65 00          	mov    0x0(%r13),%r12
  23:	4c 89 e0             	mov    %r12,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	80 3c 28 00          	cmpb   $0x0,(%rax,%rbp,1) <-- trapping instruction
  2e:	74 08                	je     0x38
  30:	4c 89 e7             	mov    %r12,%rdi
  33:	e8 c9 48 7d 00       	call   0x7d4901
  38:	4d 89 3c 24          	mov    %r15,(%r12)
  3c:	4d 85 ff             	test   %r15,%r15
  3f:	74                   	.byte 0x74

Crashes (6):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/11 03:29 upstream d58772d8520c 508909ea .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in detach_timer
2026/07/30 15:42 linux-next cc2b5f627e8c 2377cd3d .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce general protection fault in detach_timer
2026/07/30 13:11 linux-next cc2b5f627e8c 2377cd3d .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce general protection fault in detach_timer
2026/07/30 12:21 linux-next cc2b5f627e8c 2377cd3d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce general protection fault in detach_timer
2026/07/30 12:17 linux-next cc2b5f627e8c 2377cd3d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce general protection fault in detach_timer
2026/07/30 11:07 linux-next cc2b5f627e8c 2377cd3d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce general protection fault in detach_timer
* Struck through repros no longer work on HEAD.