WARNING in cancel_delayed_work_sync (2)

Status: upstream: reported on 2026/08/17 20:47
Subsystems: mmc
Labels: prio:low
[Documentation on labels]
Reported-by: syzbot+c40b1b2a25a7801239d2@syzkaller.appspotmail.com
First crash: 6d20h, last: 2h05m
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision
da352467 assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ✅ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ WARNING in cancel_delayed_work_sync (2) 2026/08/15 01:04 2026/08/15 01:04 2026/08/15 01:41 746171ee
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [mmc?] WARNING in cancel_delayed_work_sync (2) 0 (1) 2026/08/17 20:47
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream WARNING in cancel_delayed_work_sync bluetooth -1 1 1393d 1389d 0/29 closed as dup on 2022/10/31 11:09

Sample crash report:
------------[ cut here ]------------
do not call blocking ops when !TASK_RUNNING; state=1 set at [<ffffffff8953159d>] snd_rawmidi_write+0x44d/0xc60 sound/core/rawmidi.c:1614
WARNING: kernel/sched/core.c:9120 at __might_sleep+0x94/0xc0 kernel/sched/core.c:9120, CPU#1: syz.4.150/6503
Modules linked in:
CPU: 1 UID: 0 PID: 6503 Comm: syz.4.150 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:__might_sleep+0x97/0xc0 kernel/sched/core.c:9120
Code: 8b 94 24 78 18 00 00 48 85 d2 75 14 48 83 c4 08 89 ee 48 89 df 31 d2 5b 5d 41 5c e9 33 fc ff ff 48 8d 3d 7c 75 6f 0f 48 89 d1 <67> 48 0f b9 3a eb db e8 fd 3b a5 00 eb 9f 89 74 24 04 e8 22 3c a5
RSP: 0018:ffffc90000a08be8 EFLAGS: 00010282
RAX: dffffc0000000000 RBX: ffffffff8bede020 RCX: ffffffff8953159d
RDX: ffffffff8953159d RSI: 0000000000000001 RDI: ffffffff91453b80
RBP: 0000000000001187 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff88802f0d4b00
R13: 1ffff9200014118e R14: ffffffff88b96270 R15: 0000000000000001
FS:  00007fa3a79d86c0(0000) GS:ffff888123cdc000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000001e5f CR3: 00000000571e0000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 __cancel_work_sync kernel/workqueue.c:4487 [inline]
 cancel_delayed_work_sync+0xb8/0xf0 kernel/workqueue.c:4568
 mmc_free_host+0x19/0x30 drivers/mmc/core/host.c:700
 vub300_delete drivers/mmc/host/vub300.c:379 [inline]
 kref_put include/linux/kref.h:65 [inline]
 vub300_inactivity_timer_expired drivers/mmc/host/vub300.c:747 [inline]
 vub300_inactivity_timer_expired+0x42f/0x550 drivers/mmc/host/vub300.c:742
 call_timer_fn+0x19a/0x610 kernel/time/timer.c:1748
 expire_timers kernel/time/timer.c:1799 [inline]
 __run_timers+0x757/0xb00 kernel/time/timer.c:2374
 __run_timer_base kernel/time/timer.c:2386 [inline]
 __run_timer_base kernel/time/timer.c:2378 [inline]
 run_timer_base+0x114/0x190 kernel/time/timer.c:2395
 run_timer_softirq+0x1a/0x50 kernel/time/timer.c:2405
 handle_softirqs+0x1ea/0x9b0 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0x162/0x210 kernel/softirq.c:735
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
 sysvec_apic_timer_interrupt+0xa3/0xc0 arch/x86/kernel/apic/apic.c:1062
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:finish_task_switch.isra.0+0x2cd/0x10c0 kernel/sched/core.c:5361
Code: ab 0a 00 00 41 c7 87 20 0e 00 00 00 00 00 00 e9 47 04 00 00 49 8d 7f 48 e8 d0 24 ea 09 e8 eb b0 3c 00 fb 48 8d bb 00 17 00 00 <48> b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 0f b6 04 02 84
RSP: 0018:ffffc9000246f698 EFLAGS: 00000202
RAX: 0000000000017d31 RBX: ffff88802f0d4b00 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8e3a6afe RDI: ffff88802f0d6200
RBP: ffffc9000246f6f0 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: ffffffff81d6123c R12: ffff88801f292580
R13: 0000000000000001 R14: ffffffff91421aa4 R15: ffff8880b853b6c0
 context_switch kernel/sched/core.c:5513 [inline]
 __schedule+0x1264/0x6730 kernel/sched/core.c:7234
 preempt_schedule_common+0x42/0xc0 kernel/sched/core.c:7413
 preempt_schedule_thunk+0x16/0x40 arch/x86/entry/thunk.S:12
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:179 [inline]
 _raw_spin_unlock_irqrestore+0x61/0x80 kernel/locking/spinlock.c:198
 __mod_timer+0x409/0xca0 kernel/time/timer.c:1139
 add_timer+0x62/0x90 kernel/time/timer.c:1249
 schedule_timeout+0x122/0x280 kernel/time/sleep_timeout.c:98
 snd_rawmidi_write+0x492/0xc60 sound/core/rawmidi.c:1616
 do_loop_readv_writev fs/read_write.c:851 [inline]
 do_loop_readv_writev fs/read_write.c:836 [inline]
 vfs_writev+0x5ed/0xdd0 fs/read_write.c:1060
 do_writev+0x28a/0x340 fs/read_write.c:1104
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa3a6b9e0d9
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:00007fa3a79d8028 EFLAGS: 00000246 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 00007fa3a6e25fa0 RCX: 00007fa3a6b9e0d9
RDX: 0000000000000002 RSI: 0000200000000840 RDI: 0000000000000005
RBP: 00007fa3a6c35024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa3a6e26038 R14: 00007fa3a6e25fa0 R15: 00007fff81419d68
 </TASK>
----------------
Code disassembly (best guess):
   0:	8b 94 24 78 18 00 00 	mov    0x1878(%rsp),%edx
   7:	48 85 d2             	test   %rdx,%rdx
   a:	75 14                	jne    0x20
   c:	48 83 c4 08          	add    $0x8,%rsp
  10:	89 ee                	mov    %ebp,%esi
  12:	48 89 df             	mov    %rbx,%rdi
  15:	31 d2                	xor    %edx,%edx
  17:	5b                   	pop    %rbx
  18:	5d                   	pop    %rbp
  19:	41 5c                	pop    %r12
  1b:	e9 33 fc ff ff       	jmp    0xfffffc53
  20:	48 8d 3d 7c 75 6f 0f 	lea    0xf6f757c(%rip),%rdi        # 0xf6f75a3
  27:	48 89 d1             	mov    %rdx,%rcx
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	eb db                	jmp    0xc
  31:	e8 fd 3b a5 00       	call   0xa53c33
  36:	eb 9f                	jmp    0xffffffd7
  38:	89 74 24 04          	mov    %esi,0x4(%rsp)
  3c:	e8                   	.byte 0xe8
  3d:	22                   	.byte 0x22
  3e:	3c a5                	cmp    $0xa5,%al

Crashes (18):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/18 12:26 upstream ff68e5f557f6 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING in cancel_delayed_work_sync
2026/08/17 22:14 upstream 8d3ae59288f1 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING in cancel_delayed_work_sync
2026/08/17 22:12 upstream 8d3ae59288f1 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING in cancel_delayed_work_sync
2026/08/17 22:11 upstream 8d3ae59288f1 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING in cancel_delayed_work_sync
2026/08/16 15:17 upstream 3eb40771c00a 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING in cancel_delayed_work_sync
2026/08/16 11:11 upstream 3eb40771c00a 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING in cancel_delayed_work_sync
2026/08/20 15:08 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing e1e6e541c5c9 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING in cancel_delayed_work_sync
2026/08/20 06:50 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing e1e6e541c5c9 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING in cancel_delayed_work_sync
2026/08/20 06:49 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing e1e6e541c5c9 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING in cancel_delayed_work_sync
2026/08/19 15:56 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing e1e6e541c5c9 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING in cancel_delayed_work_sync
2026/08/18 17:32 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing bdab5605259b 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING in cancel_delayed_work_sync
2026/08/18 01:14 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing bdab5605259b 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING in cancel_delayed_work_sync
2026/08/17 09:59 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing bdab5605259b 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING in cancel_delayed_work_sync
2026/08/16 12:15 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing bdab5605259b 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING in cancel_delayed_work_sync
2026/08/16 05:10 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing bdab5605259b 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING in cancel_delayed_work_sync
2026/08/15 06:06 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing bdab5605259b 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING in cancel_delayed_work_sync
2026/08/14 19:04 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing bdab5605259b 6f9b3e89 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING in cancel_delayed_work_sync
2026/08/13 20:46 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 5d5fd841c346 b13552fe .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING in cancel_delayed_work_sync
* Struck through repros no longer work on HEAD.