syzbot


INFO: task hung in hub_event (3)

Status: upstream: reported on 2023/01/14 20:19
Subsystems: usb
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+a7edecbf389d11a369d4@syzkaller.appspotmail.com
First crash: 1582d, last: 1d00h
✨ AI Jobs (2)
ID Workflow Result Correct Bug Created Started Finished Revision Error
0e6b0195-a08e-4d37-89ff-ee06e80bdfca assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ✅ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ✅ INFO: task hung in hub_event (3) 2026/05/21 01:58 2026/05/21 01:58 2026/05/21 02:26 cf874a1cf36318c06202027159ddac14acf00db7

			
		
790c0256-fbdb-4057-9028-f554675fc392 repro 💥 INFO: task hung in hub_event (3) 2026/03/10 12:21 2026/03/10 12:21 2026/03/10 12:21 5c03941b7fba0fd3b0326afc981322c89fe9ba52+
unexpected git log output: "warning: unable to access '/root/.config/git/attributes': Permission denied\nwarning: unable to access '/root/.config/git/attributes': Permission denied\n9197e5949a41cfb5d4...
truncated to first 200 bytes; open job for full error
Discussions (11)
Title Replies (including bot) Last reply
[syzbot] Monthly usb report (Jun 2026) 0 (1) 2026/06/02 20:32
[syzbot] Monthly usb report (May 2024) 0 (1) 2024/05/10 08:47
[syzbot] Monthly usb report (Apr 2024) 0 (1) 2024/04/08 12:51
[syzbot] Monthly usb report (Mar 2024) 0 (1) 2024/03/08 08:53
[syzbot] Monthly usb report (Feb 2024) 0 (1) 2024/02/05 20:59
[syzbot] Monthly usb report (Jan 2024) 0 (1) 2024/01/05 13:17
[syzbot] Monthly usb report (Dec 2023) 0 (1) 2023/12/05 09:53
[syzbot] Monthly usb report (Nov 2023) 0 (1) 2023/11/03 20:48
[syzbot] Monthly usb report (May 2023) 0 (1) 2023/05/31 12:38
[syzbot] Monthly usb report 12 (17) 2023/04/10 16:42
[syzbot] INFO: task hung in hub_event (3) 0 (1) 2023/01/14 20:19
Similar bugs (12)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in hub_event usb 1 19 2451d 2626d 0/29 auto-closed as invalid on 2020/01/02 20:34
linux-6.6 INFO: task hung in hub_event 1 1 236d 236d 0/2 auto-obsoleted due to no activity on 2026/02/04 22:05
linux-4.14 INFO: task hung in hub_event 1 5 1622d 1644d 0/1 auto-closed as invalid on 2022/05/10 10:19
linux-5.15 INFO: task hung in hub_event (4) 1 3 422d 436d 0/3 auto-obsoleted due to no activity on 2025/08/02 17:03
linux-6.1 INFO: task hung in hub_event (2) 1 1 1004d 1004d 0/3 auto-obsoleted due to no activity on 2023/12/29 05:51
linux-6.1 INFO: task hung in hub_event (4) 1 4 202d 236d 0/3 auto-obsoleted due to no activity on 2026/03/10 11:30
upstream INFO: task hung in hub_event (2) usb 1 27 1621d 1666d 0/29 closed as invalid on 2022/02/08 09:40
linux-5.15 INFO: task hung in hub_event (2) 1 1 910d 910d 0/3 auto-obsoleted due to no activity on 2024/04/01 17:35
linux-6.1 INFO: task hung in hub_event (3) 1 8 439d 442d 0/3 auto-obsoleted due to no activity on 2025/07/16 18:44
linux-5.15 INFO: task hung in hub_event (3) 1 1 699d 699d 0/3 auto-obsoleted due to no activity on 2024/10/29 18:51
linux-5.15 INFO: task hung in hub_event 1 3 1022d 1185d 0/3 auto-obsoleted due to no activity on 2023/12/12 00:26
linux-6.1 INFO: task hung in hub_event 1 2 1167d 1196d 0/3 auto-obsoleted due to no activity on 2023/08/08 09:24

Sample crash report:
INFO: task kworker/1:4:15534 blocked for more than 143 seconds.
      Tainted: G             L      syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:4     state:D stack:21424 pid:15534 tgid:15534 ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: usb_hub_wq hub_event
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5504 [inline]
 __schedule+0x17d9/0x56c0 kernel/sched/core.c:7228
 __schedule_loop kernel/sched/core.c:7307 [inline]
 schedule+0x164/0x360 kernel/sched/core.c:7322
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7379
 __mutex_lock_common kernel/locking/mutex.c:726 [inline]
 __mutex_lock+0x7bf/0x1550 kernel/locking/mutex.c:821
 hub_port_connect drivers/usb/core/hub.c:5465 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5707 [inline]
 port_event drivers/usb/core/hub.c:5871 [inline]
 hub_event+0x20c9/0x4d30 drivers/usb/core/hub.c:5953
 process_one_work kernel/workqueue.c:3322 [inline]
 process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
INFO: lockdep is turned off.
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
 __sys_info lib/sys_info.c:157 [inline]
 sys_info+0x135/0x170 lib/sys_info.c:165
 check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline]
 watchdog+0xfd7/0x1030 kernel/hung_task.c:561
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:64
Code: 7c 7b 02 e9 d3 03 03 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 33 38 1c 00 fb f4 <c3> cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90
RSP: 0018:ffffc90000197e40 EFLAGS: 00000246
RAX: ffff88812535a000 RBX: ffffffff819a7300 RCX: 0000000080000001
RDX: 0000000000000001 RSI: ffffffff8c293c80 RDI: ffffffff819a7300
RBP: ffffc90000197f10 R08: ffff8880b87338db R09: 1ffff110170e671b
R10: dffffc0000000000 R11: ffffed10170e671c R12: 0000000000000000
R13: 1ffff11003b5f000 R14: 1ffff92000032fd0 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff88812535a000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555f2367af38 CR3: 000000000e746000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/kernel/process.c:766 [inline]
 default_idle+0x9/0x20 arch/x86/kernel/process.c:767
 default_idle_call+0x72/0xb0 kernel/sched/idle.c:122
 cpuidle_idle_call kernel/sched/idle.c:199 [inline]
 do_idle+0x2e0/0x540 kernel/sched/idle.c:355
 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:454
 start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:312
 common_startup_64+0x13e/0x157
 </TASK>

Crashes (901):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/06/19 23:39 upstream c98d767b3457 43bfcdb0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in hub_event
2026/06/19 22:54 upstream c98d767b3457 43bfcdb0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: task hung in hub_event
2026/06/18 18:54 upstream 9e7e66334583 a776b0d0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: task hung in hub_event
2026/06/18 17:52 upstream e771677c937d a776b0d0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: task hung in hub_event
2026/06/17 22:51 upstream 9c87e61e3c57 b62b3ded .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: task hung in hub_event
2026/06/17 20:11 upstream 9c87e61e3c57 62cc6db3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in hub_event
2026/06/17 15:27 upstream 9c87e61e3c57 62cc6db3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in hub_event
2026/06/15 23:06 upstream 0e0611827f33 50bb0618 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in hub_event
2026/06/13 14:01 upstream 062871f1371b 1d2f3589 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in hub_event
2026/06/12 11:01 upstream 2b414a95b8f7 e93da63e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in hub_event
2026/06/08 21:28 upstream 4549871118cf 656e94c6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in hub_event
2026/06/07 21:39 upstream 33d8d8ec31b5 cc095639 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in hub_event
2026/06/07 10:08 upstream 979c294509f9 cc095639 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in hub_event
2026/06/04 13:02 upstream ba3e43a9e601 197909be .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in hub_event
2026/06/03 22:25 upstream ba3e43a9e601 234057e5 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in hub_event
2026/05/30 07:49 upstream 9215e74f228f 6b4a8443 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: task hung in hub_event
2026/05/25 09:22 upstream 6a97c4d5262d c69befb3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in hub_event
2026/05/15 13:32 upstream 70eda68668d1 9cd3beaa .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: task hung in hub_event
2026/05/13 15:58 upstream 1d5dcaa3bd65 fec2a7ee .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in hub_event
2026/05/07 16:00 upstream 5862221fdded f250db59 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in hub_event
2026/04/24 17:45 upstream dd6c438c3e64 1c2b9291 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: task hung in hub_event
2026/04/24 16:02 upstream dd6c438c3e64 1c2b9291 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: task hung in hub_event
2026/04/07 06:38 upstream bfe62a454542 4440e7c2 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: task hung in hub_event
2026/04/04 20:50 upstream 7ca6d1cfec80 4440e7c2 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in hub_event
2026/03/30 07:04 upstream f242ac4a0944 356bdfc9 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: task hung in hub_event
2026/03/29 03:59 upstream be762d8b6dd7 356bdfc9 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in hub_event
2026/03/28 15:51 upstream 7df48e363130 356bdfc9 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: task hung in hub_event
2026/03/28 12:24 upstream 7df48e363130 356bdfc9 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in hub_event
2026/03/26 12:28 upstream d2a43e7f89da c6143aac .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in hub_event
2026/03/24 10:50 upstream c369299895a5 baf8bf12 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in hub_event
2026/03/23 08:00 upstream 8d8bd2a5aa98 5b92003d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in hub_event
2026/03/23 01:11 upstream 8d8bd2a5aa98 5b92003d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in hub_event
2026/03/01 07:37 upstream 9197e5949a41 43249bac .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in hub_event
2026/02/26 11:25 upstream d9d32e5bd5a4 e0f78d93 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: task hung in hub_event
2026/02/24 11:15 upstream 7dff99b35460 41d2fa6a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in hub_event
2026/02/23 20:18 upstream 6de23f81a5e0 305c0ec5 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in hub_event
2026/02/16 13:27 upstream 26a4cfaff82a 1e62d198 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: task hung in hub_event
2026/02/16 05:12 upstream bb7a3fc2c976 1e62d198 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in hub_event
2026/06/19 06:56 upstream 8c13415c8a43 d7ffd47b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 INFO: task hung in hub_event
2026/06/19 01:21 upstream 9e7e66334583 a776b0d0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 INFO: task hung in hub_event
2026/06/15 12:11 upstream 8cd9520d35a6 1d2f3589 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 INFO: task hung in hub_event
2026/04/10 15:49 upstream 9a9c8ce300cd 38c8e246 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 INFO: task hung in hub_event
2026/04/04 22:17 upstream 7ca6d1cfec80 4440e7c2 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 INFO: task hung in hub_event
2026/03/16 15:51 upstream f338e7738378 64e21424 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 INFO: task hung in hub_event
2026/03/15 19:27 upstream 267594792a71 ee8d34d6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 INFO: task hung in hub_event
2026/03/05 06:47 upstream ecc64d2dc9ff a9fe5c9e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 INFO: task hung in hub_event
2023/01/14 13:26 upstream 97ec4d559d93 a63719e7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in hub_event
2023/01/10 20:10 upstream 40c18f363a08 1dac8c7a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in hub_event
2022/12/31 00:37 upstream c8451c141e07 ab32d508 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in hub_event
2022/02/19 06:12 upstream 7993e65fdd0f 3cd800e4 .config console log report info ci-upstream-kasan-gce-root INFO: task hung in hub_event
2026/06/18 01:37 linux-next 4fa3f5fabb30 b62b3ded .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: task hung in hub_event
2026/06/17 23:41 linux-next 4fa3f5fabb30 b62b3ded .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: task hung in hub_event
2026/05/12 12:49 linux-next e98d21c170b0 d5b1a17d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce INFO: task hung in hub_event
2026/03/29 15:14 linux-next 3b058d1aeeef 356bdfc9 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: task hung in hub_event
2026/02/07 09:39 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing da87d45b1951 f20fc9f9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in hub_event
2026/05/18 14:33 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 5cbb61bf4168 55156e84 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 INFO: task hung in hub_event
* Struck through repros no longer work on HEAD.