BUG: workqueue lockup in key_garbage_collector

Status: moderation: reported on 2026/09/18 07:05
Subsystems: arm
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+dd489f70e74ca1d0ec9a@syzkaller.appspotmail.com
First crash: 4d10h, last: 4d10h
▶ ▼ ✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision
08467288 assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ✅ UserNamespace: ✅ VMGuestTrigger: ✅ VMHostTrigger: ❌ ❓ BUG: workqueue lockup in key_garbage_collector 2026/09/16 00:37 2026/09/16 00:37 2026/09/16 00:43 2daa4bb5

Sample crash report:
BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 40s!
Showing busy workqueues and worker pools:
workqueue events: flags=0x100
  pwq 2: cpus=0 node=0 flags=0x0 nice=0 active=17 refcnt=18
    in-flight: 4824:key_garbage_collector for 40s
    pending: 6*nsim_dev_hwstats_traffic_work, 3*psi_avgs_work, vmstat_shepherd, 3*ovs_dp_masks_rebalance, free_obj_work, 2*psi_avgs_work
  pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=2 refcnt=3
    in-flight: 933:reg_todo for 114s
    pending: psi_avgs_work
workqueue events_unbound: flags=0x2
  pwq 8: cpus=0-1 flags=0x6 nice=0 active=22 refcnt=23
    in-flight: 1328:cfg80211_wiphy_work for 114s ,12:cfg80211_wiphy_work for 116s ,13:cfg80211_wiphy_work for 112s ,1203:call_usermodehelper_exec_work for 121s ,58:cfg80211_wiphy_work for 111s ,184:cfg80211_wiphy_work for 94s ,5865:nsim_dev_trap_report_work for 3s
    pending: 3*nsim_dev_trap_report_work, macvlan_process_broadcast, flush_memcg_stats_dwork, 4*macvlan_process_broadcast, crng_reseed, 5*cfg80211_wiphy_work
  pwq 8: cpus=0-1 flags=0x6 nice=0 active=16 refcnt=17
    in-flight: 40:cfg80211_wiphy_work for 120s ,54:cfg80211_wiphy_work for 121s ,1827:cfg80211_wiphy_work for 119s
    pending: macvlan_process_broadcast, call_usermodehelper_exec_work, cfg80211_wiphy_work, nsim_dev_trap_report_work, cfg80211_wiphy_work, macvlan_process_broadcast, 3*cfg80211_wiphy_work, macvlan_process_broadcast, call_usermodehelper_exec_work, toggle_allocation_gate, nsim_dev_trap_report_work
workqueue events_power_efficient: flags=0x82
  pwq 8: cpus=0-1 flags=0x6 nice=0 active=11 refcnt=12
    pending: fb_flashcursor, wg_ratelimiter_gc_entries, 2*neigh_managed_work, gc_worker, 2*neigh_periodic_work, reg_check_chans_work, 3*check_lifetime
  pwq 8: cpus=0-1 flags=0x6 nice=0 active=5 refcnt=6
    pending: do_cache_clean, crda_timeout_work, 3*check_lifetime
workqueue events_dfl_long: flags=0x2
  pwq 8: cpus=0-1 flags=0x6 nice=0 active=6 refcnt=7
    pending: 6*defense_work_handler
  pwq 8: cpus=0-1 flags=0x6 nice=0 active=1 refcnt=2
    pending: defense_work_handler
workqueue netns: flags=0x6000a
  pwq 8: cpus=0-1 flags=0x6 nice=0 active=1 refcnt=4
    in-flight: 1753:cleanup_net for 130s
workqueue mm_percpu_wq: flags=0x108
  pwq 2: cpus=0 node=0 flags=0x0 nice=0 active=1 refcnt=2
    pending: vmstat_update
workqueue mld: flags=0x40108
  pwq 2: cpus=0 node=0 flags=0x0 nice=0 active=1 refcnt=15
    pending: mld_ifc_work
    inactive: 9*mld_ifc_work, mld_dad_work, 3*mld_ifc_work
workqueue ipv6_addrconf: flags=0x6000a
  pwq 8: cpus=0-1 flags=0x6 nice=0 active=1 refcnt=15 MAYDAY
    in-flight: 2822(RESCUER):addrconf_dad_work for 105s
    pending: mayday_cursor_func
    inactive: 3*addrconf_dad_work, 6*addrconf_verify_work
workqueue bat_events: flags=0x6000a
  pwq 8: cpus=0-1 flags=0x6 nice=0 active=1 refcnt=52 MAYDAY
    in-flight: 2854(RESCUER):batadv_tt_purge for 13s
    pending: mayday_cursor_func
    inactive: 2*batadv_tt_purge, 2*batadv_dat_purge, 2*batadv_bla_periodic_work, 2*batadv_dat_purge, 2*batadv_bla_periodic_work, batadv_dat_purge, batadv_bla_periodic_work, 4*batadv_purge_orig, batadv_iv_send_outstanding_bat_ogm_packet, 6*batadv_mcast_mla_update, 10*batadv_iv_send_outstanding_bat_ogm_packet, batadv_purge_orig, 6*batadv_iv_send_outstanding_bat_ogm_packet, batadv_purge_orig, 2*batadv_tt_purge, batadv_bla_periodic_work, batadv_dat_purge, batadv_tt_purge
workqueue hci0: flags=0x20012
  pwq 9: cpus=0-1 node=0 flags=0x4 nice=-20 active=1 refcnt=4
    in-flight: 4722:hci_cmd_sync_work for 27s
workqueue hci1: flags=0x20012
  pwq 9: cpus=0-1 node=0 flags=0x4 nice=-20 active=1 refcnt=4
    in-flight: 4708:hci_cmd_sync_work for 27s
workqueue hci2: flags=0x20012
  pwq 9: cpus=0-1 node=0 flags=0x4 nice=-20 active=1 refcnt=4
    in-flight: 4717:hci_cmd_sync_work for 27s
workqueue hci3: flags=0x20012
  pwq 9: cpus=0-1 node=0 flags=0x4 nice=-20 active=1 refcnt=4
    in-flight: 4712:hci_cmd_sync_work for 27s
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 2: cpus=0 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-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 2: cpus=0 node=0 flags=0x0 nice=0 active=3 refcnt=4
    pending: wg_packet_tx_worker, wg_packet_decrypt_worker, wg_packet_encrypt_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=3 refcnt=4
    pending: wg_packet_decrypt_worker, wg_packet_tx_worker, wg_packet_encrypt_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 2: cpus=0 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 2: cpus=0 node=0 flags=0x0 nice=0 active=3 refcnt=4
    pending: wg_packet_decrypt_worker, wg_packet_tx_worker, wg_packet_encrypt_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
  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=3 refcnt=4
    pending: wg_packet_decrypt_worker, wg_packet_encrypt_worker, wg_packet_tx_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 2: cpus=0 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-wg1: flags=0x6
  pwq 8: cpus=0-1 flags=0x6 nice=0 active=1 refcnt=2
    pending: wg_packet_handshake_send_worker
  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 2: cpus=0 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-wg2: flags=0x6
  pwq 8: cpus=0-1 flags=0x6 nice=0 active=1 refcnt=2
    pending: wg_packet_handshake_send_worker
  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=3 refcnt=4
    pending: wg_packet_decrypt_worker, wg_packet_encrypt_worker, wg_packet_tx_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
  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 2: cpus=0 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-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 2: cpus=0 node=0 flags=0x0 nice=0 active=3 refcnt=4
    pending: wg_packet_tx_worker, wg_packet_decrypt_worker, wg_packet_encrypt_worker
workqueue hci5: flags=0x20012
  pwq 9: cpus=0-1 node=0 flags=0x4 nice=-20 active=1 refcnt=4
    in-flight: 50:hci_cmd_sync_work for 4s
workqueue wg-crypt-wg0: flags=0x128
  pwq 2: cpus=0 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 2: cpus=0 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=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=3 refcnt=4
    pending: wg_packet_decrypt_worker, wg_packet_encrypt_worker, wg_packet_tx_worker
pool 2: cpus=0 node=0 flags=0x0 nice=0 hung=40s workers=7 idle: 4794 5581 4802 866 10 9
pool 6: cpus=1 node=0 flags=0x0 nice=0 hung=0s workers=9 idle: 5866 4801 24 4381 4809 4817 26 4810
pool 8: cpus=0-1 flags=0x6 nice=0 hung=3s workers=12 manager: 5867
pool 9: cpus=0-1 node=0 flags=0x4 nice=-20 hung=0s workers=9 idle: 4711 4721 4720 4716
Showing backtraces of busy workers in stalled worker pools:
pool 2:
task:kworker/0:5     state:R  running task     stack:0     pid:4824  tgid:4824  ppid:2      task_flags:0x4208060 flags:0x00000010
Workqueue: events key_garbage_collector
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

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/14 06:53 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 key_garbage_collector
* Struck through repros no longer work on HEAD.