INFO: task hung in rescuer_thread (3)

Status: upstream: reported syz repro on 2026/02/09 00:19
Subsystems: kernel
Labels: prio:normal
[Documentation on labels]
Reported-by: syzbot+1d6360305e34d30ab396@syzkaller.appspotmail.com
First crash: 285d, last: 24d
Cause bisection: failed (error log, bisect log)
  
Fix bisection: failed (error log, bisect log)
  
▶ ▼ ✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision
26fb86c7 assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ✅ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ INFO: task hung in rescuer_thread (3) 2026/05/24 14:39 2026/05/24 14:39 2026/05/24 15:41 c69befb3
▶ ▼ Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [kernel?] INFO: task hung in rescuer_thread (3) 0 (1) 2026/02/09 00:19
▶ ▼ Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in rescuer_thread kernel 1 19 602d 900d 0/29 auto-obsoleted due to no activity on 2025/05/29 04:51
upstream INFO: task hung in rescuer_thread (2) riscv 1 3 424d 446d 0/29 auto-obsoleted due to no activity on 2025/11/23 15:57
▶ ▼ Last patch testing requests (5)
Created Duration User Patch Repo Result
2026/10/20 21:17 26m retest repro net-next no crash job log log
2026/08/10 14:08 0m retest repro net-next error
2026/05/26 00:27 1h21m retest repro net-next log
2026/02/19 00:37 42m retest repro net-next report log
2026/02/19 00:10 57m retest repro net-next report log

Sample crash report:
INFO: task kworker/R-wg-cr:16282 blocked for more than 145 seconds.
      Tainted: G             L      syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/R-wg-cr state:D stack:28200 pid:16282 tgid:16282 ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue:  0x0 (wg-crypt-wg2)
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5533 [inline]
 __schedule+0x17db/0x58f0 kernel/sched/core.c:7284
 __schedule_loop kernel/sched/core.c:7361 [inline]
 schedule+0x164/0x2b0 kernel/sched/core.c:7376
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7433
 __mutex_lock_common kernel/locking/mutex.c:726 [inline]
 __mutex_lock+0x7c1/0x1550 kernel/locking/mutex.c:821
 worker_detach_from_pool kernel/workqueue.c:2844 [inline]
 rescuer_thread+0xc0b/0x10e0 kernel/workqueue.c:3731
 kthread+0x38b/0x480 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: task kworker/R-wg-cr:19904 blocked for more than 145 seconds.
      Tainted: G             L      syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/R-wg-cr state:D stack:27584 pid:19904 tgid:19904 ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue:  0x0 (wg-crypt-wg0)
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5533 [inline]
 __schedule+0x17db/0x58f0 kernel/sched/core.c:7284
 __schedule_loop kernel/sched/core.c:7361 [inline]
 schedule+0x164/0x2b0 kernel/sched/core.c:7376
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7433
 __mutex_lock_common kernel/locking/mutex.c:726 [inline]
 __mutex_lock+0x7c1/0x1550 kernel/locking/mutex.c:821
 worker_detach_from_pool kernel/workqueue.c:2844 [inline]
 rescuer_thread+0xc0b/0x10e0 kernel/workqueue.c:3731
 kthread+0x38b/0x480 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: task kworker/R-wg-cr:19907 blocked for more than 145 seconds.
      Tainted: G             L      syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/R-wg-cr state:D stack:27528 pid:19907 tgid:19907 ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue:  0x0 (wg-crypt-wg2)
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5533 [inline]
 __schedule+0x17db/0x58f0 kernel/sched/core.c:7284
 __schedule_loop kernel/sched/core.c:7361 [inline]
 schedule+0x164/0x2b0 kernel/sched/core.c:7376
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7433
 __mutex_lock_common kernel/locking/mutex.c:726 [inline]
 __mutex_lock+0x7c1/0x1550 kernel/locking/mutex.c:821
 worker_detach_from_pool kernel/workqueue.c:2844 [inline]
 rescuer_thread+0xc0b/0x10e0 kernel/workqueue.c:3731
 kthread+0x38b/0x480 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: task kworker/R-wg-cr:20418 blocked for more than 145 seconds.
      Tainted: G             L      syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/R-wg-cr state:D stack:30040 pid:20418 tgid:20418 ppid:2      task_flags:0x4208060 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5533 [inline]
 __schedule+0x17db/0x58f0 kernel/sched/core.c:7284
 __schedule_loop kernel/sched/core.c:7361 [inline]
 schedule+0x164/0x2b0 kernel/sched/core.c:7376
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7433
 __mutex_lock_common kernel/locking/mutex.c:726 [inline]
 __mutex_lock+0x7c1/0x1550 kernel/locking/mutex.c:821
 worker_attach_to_pool+0x31/0x390 kernel/workqueue.c:2786
 rescuer_thread+0x336/0x10e0 kernel/workqueue.c:3696
 kthread+0x38b/0x480 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>

Showing all locks held in the system:
locks held by kworker/R-kvfre/6: 1, on CPU#0:
 #0: ffffffff8ebf92a0 (wq_pool_attach_mutex){+.+.}-{4:4}, at: worker_attach_to_pool+0x31/0x390 kernel/workqueue.c:2786
locks held by kworker/0:0/9: 3, last CPU#0:
 #0: ffff8880259b6940 ((wq_completion)wg-kex-wg2#34){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #0: ffff8880259b6940 ((wq_completion)wg-kex-wg2#34){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffff8880259b6940 ((wq_completion)wg-kex-wg2#34){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
 #0: ffff8880259b6940 ((wq_completion)wg-kex-wg2#34){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
 #1: ffffc900000e7c40 ((work_completion)(&({ do { const void *__vpp_verify = (typeof((worker) + 0))((void *)0); (void)__vpp_verify; } while (0); ((typeof((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker)))))((unsigned long)((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker)))) + (((__per_cpu_offset[(cpu)]))))); })->work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #1: ffffc900000e7c40 ((work_completion)(&({ do { const void *__vpp_verify = (typeof((worker) + 0))((void *)0); (void)__vpp_verify; } while (0); ((typeof((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker)))))((unsigned long)((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker)))) + (((__per_cpu_offset[(cpu)]))))); })->work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #1: ffffc900000e7c40 ((work_completion)(&({ do { const void *__vpp_verify = (typeof((worker) + 0))((void *)0); (void)__vpp_verify; } while (0); ((typeof((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker)))))((unsigned long)((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker)))) + (((__per_cpu_offset[(cpu)]))))); })->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
 #1: ffffc900000e7c40 ((work_completion)(&({ do { const void *__vpp_verify = (typeof((worker) + 0))((void *)0); (void)__vpp_verify; } while (0); ((typeof((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker)))))((unsigned long)((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker)))) + (((__per_cpu_offset[(cpu)]))))); })->work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
 #2: ffff888025e5c888 (&handshake->lock){++++}-{4:4}, at: wg_noise_handshake_begin_session+0x36/0xbf0 drivers/net/wireguard/noise.c:822
locks held by kworker/u8:0/12: 4, on CPU#0:
 #0: ffff88807aec6940 ((wq_completion)wg-kex-wg2#33){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #0: ffff88807aec6940 ((wq_completion)wg-kex-wg2#33){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffff88807aec6940 ((wq_completion)wg-kex-wg2#33){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
 #0: ffff88807aec6940 ((wq_completion)wg-kex-wg2#33){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
 #1: ffffc90000117c40 ((work_completion)(&peer->transmit_handshake_work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #1: ffffc90000117c40 ((work_completion)(&peer->transmit_handshake_work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #1: ffffc90000117c40 ((work_completion)(&peer->transmit_handshake_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
 #1: ffffc90000117c40 ((work_completion)(&peer->transmit_handshake_work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
 #2: ffff88805ba95440 (&wg->static_identity.lock){++++}-{4:4}, at: wg_noise_handshake_create_initiation+0x12e/0x810 drivers/net/wireguard/noise.c:529
 #3: ffff888025e5c888 (&handshake->lock){++++}-{4:4}, at: wg_noise_handshake_create_initiation+0x13f/0x810 drivers/net/wireguard/noise.c:530
locks held by kworker/R-mm_pe/14: 1, on CPU#0:
 #0: ffffffff8ebf92a0 (wq_pool_attach_mutex){+.+.}-{4:4}, at: worker_detach_from_pool kernel/workqueue.c:2844 [inline]
 #0: ffffffff8ebf92a0 (wq_pool_attach_mutex){+.+.}-{4:4}, at: rescuer_thread+0xc0b/0x10e0 kernel/workqueue.c:3731
locks held by pr/ttyS0/16: 1, last CPU#0:
 #0: ffffffff8ec364d8 (console_srcu){....}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:314 [inline]
 #0: ffffffff8ec364d8 (console_srcu){....}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:439 [inline]
 #0: ffffffff8ec364d8 (console_srcu){....}-{0:0}, at: console_srcu_read_lock+0x30/0x60 kernel/printk/printk.c:291
locks held by kworker/1:1/30: 3, last CPU#1:

Crashes (13):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/29 14:27 upstream 72d3fcf802c4 7bf4ea23 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: task hung in rescuer_thread
2026/06/13 11:11 upstream 062871f1371b 1d2f3589 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in rescuer_thread
2026/01/10 22:13 upstream b6151c4e60e5 d1b870e1 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: task hung in rescuer_thread
2026/09/23 16:31 net 9c572a83037a abce1216 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in rescuer_thread
2026/08/26 09:52 net dc4b95b8fee9 6a91adb4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in rescuer_thread
2026/08/19 11:48 net 564973a259ec 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in rescuer_thread
2026/06/28 01:48 net 32f1c2bbb26a fb92f11c .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in rescuer_thread
2026/06/26 03:38 net 805185b7c7a1 432fd51a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in rescuer_thread
2026/04/27 10:47 net 254f49634ee1 0f700595 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in rescuer_thread
2026/06/18 23:25 net-next b85966adbf5d a776b0d0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: task hung in rescuer_thread
2026/05/11 11:40 net-next 63751099502d e6eb7c0b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: task hung in rescuer_thread
2026/02/05 00:01 net-next 9a9424c756fe ea10c935 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: task hung in rescuer_thread
2026/09/28 06:52 linux-next f5f84daefcd9 a3c7249d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: task hung in rescuer_thread
* Struck through repros no longer work on HEAD.