BUG: workqueue lockup in wg_packet_decrypt_worker

Status: upstream: reported on 2026/09/15 21:33
Subsystems: wireguard
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+d0d2f1a65f45b319d25d@syzkaller.appspotmail.com
First crash: 5d23h, last: 1h35m
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision
83add95e assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ✅ PeripheralTrigger: ❌ RemoteTrigger: ✅ Unprivileged: ✅ UserNamespace: ✅ VMGuestTrigger: ❌ VMHostTrigger: ❌ BUG: workqueue lockup in wg_packet_decrypt_worker 2026/09/11 01:03 2026/09/11 01:03 2026/09/11 01:41 1fe56c0a
Discussions (1)
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[syzbot] [wireguard?] BUG: workqueue lockup in wg_packet_decrypt_worker 0 (1) 2026/09/15 21:33

Sample crash report:
BUG: workqueue lockup - pool cpus=1 node=0 flags=0x0 nice=0 stuck for 45s!
Showing busy workqueues and worker pools:
workqueue events: flags=0x100
  pwq 2: cpus=0 node=0 flags=0x0 nice=0 active=6 refcnt=7
    pending: vmstat_shepherd, 2*psi_avgs_work, 3*ovs_dp_masks_rebalance
  pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=18 refcnt=19
    pending: 2*psi_avgs_work, 3*ovs_dp_masks_rebalance, xfrm_state_gc_task, psi_avgs_work, delayed_vfree_work, 8*nsim_dev_hwstats_traffic_work, psi_avgs_work, free_obj_work
workqueue events_unbound: flags=0x2
  pwq 8: cpus=0-1 flags=0x6 nice=0 active=20 refcnt=21
    in-flight: 3055:cfg80211_wiphy_work for 75s cfg80211_wiphy_work ,54:nsim_dev_trap_report_work for 6s ,431:cfg80211_wiphy_work for 73s cfg80211_wiphy_work ,348:cfg80211_wiphy_work for 91s cfg80211_wiphy_work ,1617:cfg80211_wiphy_work for 76s cfg80211_wiphy_work ,12:cfg80211_wiphy_work for 93s cfg80211_wiphy_work ,1777:nsim_dev_trap_report_work for 11s ,40:cfg80211_wiphy_work for 92s cfg80211_wiphy_work ,3203:nsim_dev_trap_report_work for 1s
    pending: nsim_dev_trap_report_work, toggle_allocation_gate, 2*nsim_dev_trap_report_work, cfg80211_wiphy_work
  pwq 8: cpus=0-1 flags=0x6 nice=0 active=7 refcnt=8
    in-flight: 13:linkwatch_event for 95s ,3020:cfg80211_wiphy_work for 89s cfg80211_wiphy_work ,3157:cfg80211_wiphy_work for 60s cfg80211_wiphy_work
    pending: 2*nsim_dev_trap_report_work
workqueue events_power_efficient: flags=0x82
  pwq 8: cpus=0-1 flags=0x6 nice=0 active=6 refcnt=7
    in-flight: 1756:neigh_periodic_work for 6s ,284:reg_check_chans_work for 75s
    pending: neigh_periodic_work, wg_ratelimiter_gc_entries, 2*neigh_managed_work
  pwq 8: cpus=0-1 flags=0x6 nice=0 active=1 refcnt=2
    pending: gc_worker
workqueue events_dfl_long: flags=0x2
  pwq 8: cpus=0-1 flags=0x6 nice=0 active=6 refcnt=7
    pending: 6*defense_work_handler
workqueue mm_percpu_wq: flags=0x108
  pwq 2: cpus=0 node=0 flags=0x0 nice=0 active=1 refcnt=2
    pending: vmstat_update
  pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=1 refcnt=2
    pending: vmstat_update
workqueue ipv6_addrconf: flags=0x6000a
  pwq 8: cpus=0-1 flags=0x6 nice=0 active=1 refcnt=9
    in-flight: 59:addrconf_verify_work for 78s
    inactive: 5*addrconf_verify_work
workqueue bat_events: flags=0x6000a
  pwq 8: cpus=0-1 flags=0x6 nice=0 active=1 refcnt=45 MAYDAY
    in-flight: 2855(RESCUER):batadv_tt_purge for 18s
    inactive: batadv_tt_purge, batadv_mcast_mla_update, batadv_tt_purge, batadv_dat_purge, batadv_bla_periodic_work, batadv_dat_purge, 2*batadv_bla_periodic_work, batadv_dat_purge, batadv_mcast_mla_update, batadv_bla_periodic_work, batadv_dat_purge, 2*batadv_mcast_mla_update, 2*batadv_iv_send_outstanding_bat_ogm_packet, batadv_purge_orig, 3*batadv_iv_send_outstanding_bat_ogm_packet, 2*batadv_purge_orig, 5*batadv_iv_send_outstanding_bat_ogm_packet, batadv_purge_orig, batadv_iv_send_outstanding_bat_ogm_packet, batadv_mcast_mla_update, 4*batadv_iv_send_outstanding_bat_ogm_packet, batadv_purge_orig, batadv_bla_periodic_work, batadv_dat_purge, 2*batadv_tt_purge
workqueue wg-kex-wg0: flags=0x124
  pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=1 refcnt=2
    pending: wg_packet_handshake_receive_worker
workqueue wg-kex-wg0: flags=0x6
  pwq 8: cpus=0-1 flags=0x6 nice=0 active=1 refcnt=2
    pending: wg_packet_handshake_send_worker
workqueue wg-crypt-wg0: flags=0x128
  pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=2 refcnt=3
    pending: wg_packet_encrypt_worker, wg_packet_tx_worker
workqueue wg-kex-wg1: flags=0x124
  pwq 2: cpus=0 node=0 flags=0x0 nice=0 active=2 refcnt=3
    in-flight: 10:wg_packet_handshake_receive_worker for 46s
    pending: wg_packet_handshake_receive_worker
  pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=1 refcnt=2
    pending: wg_packet_handshake_receive_worker
workqueue wg-kex-wg1: flags=0x6
  pwq 8: cpus=0-1 flags=0x6 nice=0 active=1 refcnt=2
    pending: wg_packet_handshake_send_worker
workqueue wg-crypt-wg1: flags=0x128
  pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=3 refcnt=4
    pending: wg_packet_encrypt_worker, wg_packet_tx_worker, wg_packet_decrypt_worker
workqueue wg-kex-wg0: flags=0x6
  pwq 8: cpus=0-1 flags=0x6 nice=0 active=1 refcnt=2
    in-flight: 3495:wg_packet_handshake_send_worker for 4s
workqueue wg-crypt-wg0: flags=0x128
  pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=2 refcnt=3
    pending: wg_packet_tx_worker, wg_packet_encrypt_worker
workqueue wg-kex-wg2: flags=0x124
  pwq 2: cpus=0 node=0 flags=0x0 nice=0 active=1 refcnt=2
    in-flight: 4477:wg_packet_handshake_receive_worker for 12s
  pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=1 refcnt=2
    pending: wg_packet_handshake_receive_worker
workqueue wg-kex-wg2: flags=0x6
  pwq 8: cpus=0-1 flags=0x6 nice=0 active=2 refcnt=3
    pending: 2*wg_packet_handshake_send_worker
workqueue wg-crypt-wg2: flags=0x128
  pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=3 refcnt=4
    pending: wg_packet_encrypt_worker, wg_packet_decrypt_worker, wg_packet_tx_worker
workqueue wg-crypt-wg1: flags=0x128
  pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=2 refcnt=3
    pending: wg_packet_encrypt_worker, wg_packet_tx_worker
workqueue wg-kex-wg2: flags=0x124
  pwq 2: cpus=0 node=0 flags=0x0 nice=0 active=1 refcnt=2
    in-flight: 9:wg_packet_handshake_receive_worker for 20s
  pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=1 refcnt=2
    pending: wg_packet_handshake_receive_worker
workqueue wg-crypt-wg2: flags=0x128
  pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=4 refcnt=5
    in-flight: 4889:wg_packet_decrypt_worker for 45s
    pending: wg_packet_tx_worker, wg_packet_encrypt_worker, wg_packet_decrypt_worker
workqueue hci0: flags=0x20012
  pwq 9: cpus=0-1 node=0 flags=0x4 nice=-20 active=1 refcnt=4
    in-flight: 4723:hci_cmd_sync_work for 84s
workqueue wg-kex-wg0: flags=0x124
  pwq 2: cpus=0 node=0 flags=0x0 nice=0 active=1 refcnt=2
    pending: wg_packet_handshake_receive_worker
  pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=1 refcnt=2
    pending: wg_packet_handshake_receive_worker
workqueue wg-crypt-wg0: flags=0x128
  pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=3 refcnt=4
    in-flight: 24:wg_packet_tx_worker for 45s
    pending: wg_packet_encrypt_worker, wg_packet_tx_worker
workqueue wg-kex-wg1: flags=0x124
  pwq 2: cpus=0 node=0 flags=0x0 nice=0 active=1 refcnt=2
    in-flight: 4799:wg_packet_handshake_receive_worker for 17s
  pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=1 refcnt=2
    pending: wg_packet_handshake_receive_worker
workqueue wg-crypt-wg1: flags=0x128
  pwq 2: cpus=0 node=0 flags=0x0 nice=0 active=1 refcnt=2
    pending: wg_packet_encrypt_worker
  pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=3 refcnt=4
    pending: wg_packet_encrypt_worker, wg_packet_tx_worker, wg_packet_decrypt_worker
workqueue wg-kex-wg2: flags=0x124
  pwq 2: cpus=0 node=0 flags=0x0 nice=0 active=1 refcnt=2
    pending: wg_packet_handshake_receive_worker
  pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=1 refcnt=2
    pending: wg_packet_handshake_receive_worker
workqueue wg-kex-wg2: flags=0x6
  pwq 8: cpus=0-1 flags=0x6 nice=0 active=2 refcnt=3
    pending: 2*wg_packet_handshake_send_worker
workqueue wg-crypt-wg2: flags=0x128
  pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=3 refcnt=4
    pending: wg_packet_decrypt_worker, wg_packet_encrypt_worker, wg_packet_tx_worker
workqueue hci3: flags=0x20012
  pwq 9: cpus=0-1 node=0 flags=0x4 nice=-20 active=1 refcnt=4
    in-flight: 4726:hci_cmd_sync_work for 78s
workqueue wg-kex-wg0: flags=0x124
  pwq 2: cpus=0 node=0 flags=0x0 nice=0 active=1 refcnt=2
    in-flight: 4840:wg_packet_handshake_receive_worker for 11s
  pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=1 refcnt=2
    pending: wg_packet_handshake_receive_worker
workqueue wg-crypt-wg0: flags=0x128
  pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=2 refcnt=3
    pending: wg_packet_tx_worker, wg_packet_encrypt_worker
workqueue wg-kex-wg1: flags=0x124
  pwq 2: cpus=0 node=0 flags=0x0 nice=0 active=1 refcnt=2
    in-flight: 4806:wg_packet_handshake_receive_worker for 19s
  pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=1 refcnt=2
    pending: wg_packet_handshake_receive_worker
workqueue wg-crypt-wg1: flags=0x128
  pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=3 refcnt=4
    pending: wg_packet_encrypt_worker, wg_packet_tx_worker, wg_packet_decrypt_worker
workqueue wg-kex-wg2: flags=0x124
  pwq 2: cpus=0 node=0 flags=0x0 nice=0 active=1 refcnt=2
    in-flight: 4827:wg_packet_handshake_receive_worker for 6s
  pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=1 refcnt=2
    pending: wg_packet_handshake_receive_worker
workqueue wg-kex-wg2: flags=0x6
  pwq 8: cpus=0-1 flags=0x6 nice=0 active=1 refcnt=2
    pending: wg_packet_handshake_send_worker
workqueue wg-crypt-wg2: flags=0x128
  pwq 2: cpus=0 node=0 flags=0x0 nice=0 active=1 refcnt=2
    pending: wg_packet_decrypt_worker
  pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=3 refcnt=4
    pending: wg_packet_decrypt_worker, wg_packet_encrypt_worker, wg_packet_tx_worker
workqueue wg-kex-wg0: flags=0x124
  pwq 2: cpus=0 node=0 flags=0x0 nice=0 active=1 refcnt=2
    pending: wg_packet_handshake_receive_worker
workqueue wg-kex-wg0: flags=0x6
  pwq 8: cpus=0-1 flags=0x6 nice=0 active=1 refcnt=2
    pending: wg_packet_handshake_send_worker
workqueue wg-crypt-wg0: flags=0x128
  pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=2 refcnt=3
    pending: wg_packet_encrypt_worker, wg_packet_tx_worker
workqueue wg-crypt-wg1: flags=0x128
  pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=3 refcnt=4
    pending: wg_packet_encrypt_worker, wg_packet_tx_worker, wg_packet_decrypt_worker
workqueue wg-kex-wg2: flags=0x124
  pwq 2: cpus=0 node=0 flags=0x0 nice=0 active=1 refcnt=2
    in-flight: 1159:wg_packet_handshake_receive_worker for 23s
  pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=1 refcnt=2
    pending: wg_packet_handshake_receive_worker
workqueue wg-crypt-wg2: flags=0x128
  pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=3 refcnt=4
    pending: wg_packet_tx_worker, wg_packet_decrypt_worker, wg_packet_encrypt_worker
pool 2: cpus=0 node=0 flags=0x0 nice=0 hung=6s workers=10 idle: 4820 4807
pool 6: cpus=1 node=0 flags=0x0 nice=0 hung=45s workers=8 idle: 5732 5459 26 4798 868 5730
pool 8: cpus=0-1 flags=0x6 nice=0 hung=1s workers=17 manager: 6529
pool 9: cpus=0-1 node=0 flags=0x4 nice=-20 hung=0s workers=8 idle: 4721 4713 4718 4717 50 4720
Showing backtraces of busy workers in stalled worker pools:
pool 6:
task:kworker/1:4     state:R  running task     stack:0     pid:4889  tgid:4889  ppid:2      task_flags:0x4208060 flags:0x00000010
Workqueue: wg-crypt-wg2 wg_packet_decrypt_worker
Call trace:
 __switch_to+0x2b4/0x6e4 arch/arm64/kernel/process.c:775 (T)
 context_switch kernel/sched/core.c:5520 [inline]
 __schedule+0x1370/0x2d80 kernel/sched/core.c:7270
 preempt_schedule_common+0xd4/0x190 kernel/sched/core.c:7449
 preempt_schedule kernel/sched/core.c:7473 [inline]
 class_preempt_destructor include/linux/preempt.h:500 [inline]
 try_to_wake_up+0x5f8/0xdc4 kernel/sched/core.c:4432
 wake_up_process+0x18/0x24 kernel/sched/core.c:4557
 process_one_work kernel/workqueue.c:3355 [inline]
 process_scheduled_works+0x744/0x1250 kernel/workqueue.c:3470
 worker_thread+0x798/0xbd0 kernel/workqueue.c:3551
 kthread+0x304/0x3d4 kernel/kthread.c:436
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:838
pool 6:
task:kworker/1:0     state:R  running task     stack:0     pid:24    tgid:24    ppid:2      task_flags:0x4208060 flags:0x00000010
Workqueue: wg-crypt-wg0 wg_packet_tx_worker
Call trace:
 __switch_to+0x2b4/0x6e4 arch/arm64/kernel/process.c:775 (T)
 context_switch kernel/sched/core.c:5520 [inline]
 __schedule+0x1370/0x2d80 kernel/sched/core.c:7270
 preempt_schedule_common+0xd4/0x190 kernel/sched/core.c:7449
 preempt_schedule+0x60/0x78 kernel/sched/core.c:7473
 __local_bh_enable_ip+0x20c/0x35c kernel/softirq.c:480
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 rcu_read_unlock_bh include/linux/rcupdate.h:923 [inline]
 keep_key_fresh drivers/net/wireguard/send.c:135 [inline]
 wg_packet_create_data_done drivers/net/wireguard/send.c:259 [inline]
 wg_packet_tx_worker+0x520/0x75c drivers/net/wireguard/send.c:276
 process_one_work kernel/workqueue.c:3387 [inline]
 process_scheduled_works+0x91c/0x1250 kernel/workqueue.c:3470
 worker_thread+0x798/0xbd0 kernel/workqueue.c:3551
 kthread+0x304/0x3d4 kernel/kthread.c:436
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:838

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/15 21:32 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 5445d6419962 81a27d1a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 BUG: workqueue lockup in wg_packet_decrypt_worker
2026/09/13 21:01 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 5445d6419962 70a60e12 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 BUG: workqueue lockup in wg_packet_decrypt_worker
2026/09/12 05:17 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 5445d6419962 70a60e12 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 BUG: workqueue lockup in wg_packet_decrypt_worker
2026/09/09 23:59 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 5445d6419962 4e8b1cc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 BUG: workqueue lockup in wg_packet_decrypt_worker
2026/09/09 23:35 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 5445d6419962 4e8b1cc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 BUG: workqueue lockup in wg_packet_decrypt_worker
* Struck through repros no longer work on HEAD.