syzbot


INFO: task hung in __lru_add_drain_all (3)

Status: upstream: reported on 2026/03/10 22:55
Reported-by: syzbot+7071e1cb807dc51207d5@syzkaller.appspotmail.com
First crash: 43d, last: 9d16h
Similar bugs (8)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.6 INFO: task hung in __lru_add_drain_all 1 1 169d 169d 0/2 auto-obsoleted due to no activity on 2026/02/12 06:31
linux-6.1 INFO: task hung in __lru_add_drain_all (2) 1 1 325d 325d 0/3 auto-obsoleted due to no activity on 2025/09/09 22:30
linux-5.15 INFO: task hung in __lru_add_drain_all 1 1 1095d 1095d 0/3 auto-obsoleted due to no activity on 2023/08/21 02:18
linux-6.1 INFO: task hung in __lru_add_drain_all 1 1 705d 705d 0/3 auto-obsoleted due to no activity on 2024/08/25 20:43
upstream INFO: task hung in __lru_add_drain_all (2) mm 1 syz error 272 367d 705d 0/29 auto-obsoleted due to no activity on 2025/06/29 18:01
upstream INFO: task hung in __lru_add_drain_all net 1 C done error 71 892d 1692d 0/29 auto-obsoleted due to no activity on 2024/02/20 10:46
linux-5.15 INFO: task hung in __lru_add_drain_all (2) 1 1 635d 635d 0/3 auto-obsoleted due to no activity on 2024/11/03 03:56
android-6-12 INFO: task hung in __lru_add_drain_all 1 1 170d 170d 0/1 auto-obsoleted due to no activity on 2026/02/01 19:21

Sample crash report:
INFO: task khugepaged:34 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:khugepaged      state:D stack:27920 pid:34    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x11d1/0x40e0 kernel/sched/core.c:6562
 schedule+0xb9/0x180 kernel/sched/core.c:6638
 schedule_timeout+0xbd/0x2d0 kernel/time/timer.c:2144
 do_wait_for_common kernel/sched/completion.c:85 [inline]
 __wait_for_common kernel/sched/completion.c:106 [inline]
 wait_for_common kernel/sched/completion.c:117 [inline]
 wait_for_completion+0x2c7/0x5a0 kernel/sched/completion.c:138
 __flush_work+0x952/0xae0 kernel/workqueue.c:3076
 __lru_add_drain_all+0x6a0/0x800 mm/swap.c:910
 khugepaged_do_scan mm/khugepaged.c:2453 [inline]
 khugepaged+0x183/0x19a0 mm/khugepaged.c:2522
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
INFO: task kworker/u4:27:11957 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:27   state:D stack:23152 pid:11957 ppid:2      flags:0x00004000
Workqueue: events_unbound fsnotify_connector_destroy_workfn
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x11d1/0x40e0 kernel/sched/core.c:6562
 schedule+0xb9/0x180 kernel/sched/core.c:6638
 schedule_timeout+0xbd/0x2d0 kernel/time/timer.c:2144
 do_wait_for_common kernel/sched/completion.c:85 [inline]
 __wait_for_common kernel/sched/completion.c:106 [inline]
 wait_for_common kernel/sched/completion.c:117 [inline]
 wait_for_completion+0x2c7/0x5a0 kernel/sched/completion.c:138
 __synchronize_srcu+0x2b9/0x350 kernel/rcu/srcutree.c:1243
 fsnotify_connector_destroy_workfn+0x40/0xa0 fs/notify/mark.c:234
 process_one_work+0x8a2/0x1160 kernel/workqueue.c:2292
 worker_thread+0xaa2/0x1270 kernel/workqueue.c:2439
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
INFO: task kworker/u4:30:12916 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:30   state:D stack:23088 pid:12916 ppid:2      flags:0x00004000
Workqueue: events_unbound fsnotify_mark_destroy_workfn
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x11d1/0x40e0 kernel/sched/core.c:6562
 schedule+0xb9/0x180 kernel/sched/core.c:6638
 schedule_timeout+0xbd/0x2d0 kernel/time/timer.c:2144
 do_wait_for_common kernel/sched/completion.c:85 [inline]
 __wait_for_common kernel/sched/completion.c:106 [inline]
 wait_for_common kernel/sched/completion.c:117 [inline]
 wait_for_completion+0x2c7/0x5a0 kernel/sched/completion.c:138
 __synchronize_srcu+0x2b9/0x350 kernel/rcu/srcutree.c:1243
 fsnotify_mark_destroy_workfn+0x106/0x2f0 fs/notify/mark.c:924
 process_one_work+0x8a2/0x1160 kernel/workqueue.c:2292
 worker_thread+0xaa2/0x1270 kernel/workqueue.c:2439
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
INFO: task kworker/0:14:17687 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:14    state:D stack:23184 pid:17687 ppid:2      flags:0x00004000
Workqueue: ipv6_addrconf addrconf_verify_work
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x11d1/0x40e0 kernel/sched/core.c:6562
 schedule+0xb9/0x180 kernel/sched/core.c:6638
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6697
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x562/0xaf0 kernel/locking/mutex.c:747
 addrconf_verify_work+0x15/0x30 net/ipv6/addrconf.c:4672
 process_one_work+0x8a2/0x1160 kernel/workqueue.c:2292
 worker_thread+0xaa2/0x1270 kernel/workqueue.c:2439
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
INFO: task syz.7.5665:25954 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.7.5665      state:D stack:25424 pid:25954 ppid:23655  flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x11d1/0x40e0 kernel/sched/core.c:6562
 schedule+0xb9/0x180 kernel/sched/core.c:6638
 synchronize_rcu_expedited+0x6e6/0x890 kernel/rcu/tree_exp.h:977
 synchronize_rcu+0x128/0x3f0 kernel/rcu/tree.c:3580
 packet_release+0x98f/0xc40 net/packet/af_packet.c:3213
 __sock_release net/socket.c:654 [inline]
 sock_close+0xd5/0x240 net/socket.c:1399
 __fput+0x22c/0x920 fs/file_table.c:320
 task_work_run+0x1d0/0x260 kernel/task_work.c:203
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f164c99c819
RSP: 002b:00007ffec8a81fc8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007ffec8a820b0 RCX: 00007f164c99c819
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00000000001c541f R08: 0000000000000001 R09: 0000000000000000
R10: 0000001b2ff20000 R11: 0000000000000246 R12: 00007ffec8a820f0
R13: 00007f164cc15fac R14: 00000000001c553d R15: 00007f164cc15fa0
 </TASK>
INFO: task syz.0.5667:25960 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.5667      state:D stack:26224 pid:25960 ppid:15519  flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x11d1/0x40e0 kernel/sched/core.c:6562
 schedule+0xb9/0x180 kernel/sched/core.c:6638
 exp_funnel_lock kernel/rcu/tree_exp.h:314 [inline]
 synchronize_rcu_expedited+0x7ad/0x890 kernel/rcu/tree_exp.h:962
 packet_release+0x98f/0xc40 net/packet/af_packet.c:3213
 __sock_release net/socket.c:654 [inline]
 sock_close+0xd5/0x240 net/socket.c:1399
 __fput+0x22c/0x920 fs/file_table.c:320
 task_work_run+0x1d0/0x260 kernel/task_work.c:203
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7eff18d9c819
RSP: 002b:00007ffc2bc1abb8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007eff19017da0 RCX: 00007eff18d9c819
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007eff19017da0 R08: 0000000000000006 R09: 0000000000000000
R10: 00007eff19017cb0 R11: 0000000000000246 R12: 00000000001c5836
R13: 00007eff1901609c R14: 00000000001c55a7 R15: 00007eff19016090
 </TASK>
INFO: task syz.0.5667:25962 blocked for more than 145 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.5667      state:D stack:25296 pid:25962 ppid:15519  flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x11d1/0x40e0 kernel/sched/core.c:6562
 schedule+0xb9/0x180 kernel/sched/core.c:6638
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6697
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x562/0xaf0 kernel/locking/mutex.c:747
 exp_funnel_lock kernel/rcu/tree_exp.h:323 [inline]
 synchronize_rcu_expedited+0x3c0/0x890 kernel/rcu/tree_exp.h:962
 synchronize_rcu+0x128/0x3f0 kernel/rcu/tree.c:3580
 lockdep_unregister_key+0x4d2/0x550 kernel/locking/lockdep.c:6374
 __qdisc_destroy+0x128/0x430 net/sched/sch_generic.c:1081
 taprio_destroy+0x25f/0x4b0 net/sched/sch_taprio.c:1742
 qdisc_create+0xe3b/0x10b0 net/sched/sch_api.c:-1
 tc_modify_qdisc+0xb5f/0x1d10 net/sched/sch_api.c:-1
 rtnetlink_rcv_msg+0x87c/0xfc0 net/core/rtnetlink.c:6157
 netlink_rcv_skb+0x1fb/0x450 net/netlink/af_netlink.c:2511
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x74d/0x8d0 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x8ad/0xbd0 net/netlink/af_netlink.c:1872
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg net/socket.c:730 [inline]
 ____sys_sendmsg+0x5be/0x970 net/socket.c:2518
 ___sys_sendmsg+0x2a2/0x360 net/socket.c:2572
 __sys_sendmsg net/socket.c:2601 [inline]
 __do_sys_sendmsg net/socket.c:2610 [inline]
 __se_sys_sendmsg+0x1bb/0x2a0 net/socket.c:2608
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7eff18d9c819
RSP: 002b:00007eff19b9b028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007eff19015fa0 RCX: 00007eff18d9c819
RDX: 0000000000048004 RSI: 00002000000007c0 RDI: 0000000000000006
RBP: 00007eff18e32c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007eff19016038 R14: 00007eff19015fa0 R15: 00007ffc2bc1aa58
 </TASK>
INFO: task syz.4.5666:25964 blocked for more than 145 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.5666      state:D stack:27152 pid:25964 ppid:16953  flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x11d1/0x40e0 kernel/sched/core.c:6562
 schedule+0xb9/0x180 kernel/sched/core.c:6638
 exp_funnel_lock kernel/rcu/tree_exp.h:314 [inline]
 synchronize_rcu_expedited+0x7ad/0x890 kernel/rcu/tree_exp.h:962
 synchronize_rcu+0x128/0x3f0 kernel/rcu/tree.c:3580
 __sched_core_enable kernel/sched/core.c:382 [inline]
 sched_core_get+0xab/0x1c0 kernel/sched/core.c:401
 sched_core_alloc_cookie+0x71/0xa0 kernel/sched/core_sched.c:18
 sched_core_share_pid+0x336/0x770 kernel/sched/core_sched.c:185
 __do_sys_prctl kernel/sys.c:2669 [inline]
 __se_sys_prctl+0x237/0x1100 kernel/sys.c:2395
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f4cc3f9c819
RSP: 002b:00007f4cc4e6c028 EFLAGS: 00000246 ORIG_RAX: 000000000000009d
RAX: ffffffffffffffda RBX: 00007f4cc4215fa0 RCX: 00007f4cc3f9c819
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 000000000000003e
RBP: 00007f4cc4032c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4cc4216038 R14: 00007f4cc4215fa0 R15: 00007ffe220017b8
 </TASK>
INFO: task syz.5.5668:25968 blocked for more than 146 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.5.5668      state:D stack:26224 pid:25968 ppid:18146  flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x11d1/0x40e0 kernel/sched/core.c:6562
 schedule+0xb9/0x180 kernel/sched/core.c:6638
 exp_funnel_lock kernel/rcu/tree_exp.h:314 [inline]
 synchronize_rcu_expedited+0x7ad/0x890 kernel/rcu/tree_exp.h:962
 packet_release+0x98f/0xc40 net/packet/af_packet.c:3213
 __sock_release net/socket.c:654 [inline]
 sock_close+0xd5/0x240 net/socket.c:1399
 __fput+0x22c/0x920 fs/file_table.c:320
 task_work_run+0x1d0/0x260 kernel/task_work.c:203
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f6ef1d9c819
RSP: 002b:00007fffe840c128 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007fffe840c210 RCX: 00007f6ef1d9c819
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00000000001c5d66 R08: 0000000000000001 R09: 0000000000000000
R10: 0000001b31120000 R11: 0000000000000246 R12: 00007fffe840c250
R13: 00007f6ef2015fac R14: 00000000001c5e53 R15: 00007f6ef2015fa0
 </TASK>
INFO: task dhcpcd:25972 blocked for more than 146 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:dhcpcd          state:D stack:24944 pid:25972 ppid:3933   flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x11d1/0x40e0 kernel/sched/core.c:6562
 schedule+0xb9/0x180 kernel/sched/core.c:6638
 exp_funnel_lock kernel/rcu/tree_exp.h:314 [inline]
 synchronize_rcu_expedited+0x7ad/0x890 kernel/rcu/tree_exp.h:962
 __unregister_prot_hook+0x3f7/0x570 net/packet/af_packet.c:383
 packet_do_bind+0x519/0xce0 net/packet/af_packet.c:3285
 __sys_bind+0x2e9/0x3e0 net/socket.c:1810
 __do_sys_bind net/socket.c:1821 [inline]
 __se_sys_bind net/socket.c:1819 [inline]
 __x64_sys_bind+0x76/0x80 net/socket.c:1819
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fb4cada42d7
RSP: 002b:00007fff45c076f8 EFLAGS: 00000213 ORIG_RAX: 0000000000000031
RAX: ffffffffffffffda RBX: 000055dd4da8ce00 RCX: 00007fb4cada42d7
RDX: 0000000000000014 RSI: 00007fff45c07710 RDI: 0000000000000003
RBP: 000055dd2b2094b0 R08: 00007fb4cae73ac0 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000213 R12: 0000000000000000
R13: 000055dd4da885f0 R14: 0000000000000000 R15: 000055dd2b21eac0
 </TASK>

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
 #0: ffffffff8cb2df30 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
 #0: ffffffff8cb2e750 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/28:
 #0: ffffffff8cb2d5a0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #0: ffffffff8cb2d5a0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #0: ffffffff8cb2d5a0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6513
1 lock held by khugepaged/34:
 #0: ffffffff8cbd4668 (lock#3){+.+.}-{3:3}, at: __lru_add_drain_all+0x66/0x800 mm/swap.c:865
2 locks held by getty/4027:
 #0: ffff88802fe7d098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
 #1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x429/0x1390 drivers/tty/n_tty.c:2198
3 locks held by kworker/1:4/4316:
2 locks held by kworker/u4:27/11957:
 #0: ffff888017479138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #1: ffffc90003ba7d00 (connector_reaper_work){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
2 locks held by kworker/u4:30/12916:
 #0: ffff888017479138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #1: ffffc9000e337d00 ((reaper_work).work){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
4 locks held by kworker/u4:35/15431:
 #0: ffff8880b8f3ab18 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xa5/0x140 kernel/sched/core.c:546
 #1: ffffc900039f7d00 ((work_completion)(&(&nsim_dev->trap_data->trap_report_dw)->work)){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8c9c9e70 (cpu_hotplug_lock){++++}-{0:0}, at: static_key_enable+0xe/0x20 kernel/jump_label.c:219
 #3: ffffffff8cbc9648 (jump_label_mutex){+.+.}-{3:3}, at: jump_label_lock kernel/jump_label.c:27 [inline]
 #3: ffffffff8cbc9648 (jump_label_mutex){+.+.}-{3:3}, at: static_key_enable_cpuslocked+0xc2/0x240 kernel/jump_label.c:204
3 locks held by kworker/0:14/17687:
 #0: ffff88814cb55538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #1: ffffc900034e7d00 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8dd47de8 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_verify_work+0x15/0x30 net/ipv6/addrconf.c:4672
2 locks held by syz.7.5665/25954:
 #0: ffff88807072f410 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
 #0: ffff88807072f410 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: __sock_release net/socket.c:653 [inline]
 #0: ffff88807072f410 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: sock_close+0x90/0x240 net/socket.c:1399
 #1: ffffffff8cb33278 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:291 [inline]
 #1: ffffffff8cb33278 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x2ec/0x890 kernel/rcu/tree_exp.h:962
1 lock held by syz.0.5667/25960:
 #0: ffff888053e85c10 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
 #0: ffff888053e85c10 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: __sock_release net/socket.c:653 [inline]
 #0: ffff888053e85c10 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: sock_close+0x90/0x240 net/socket.c:1399
2 locks held by syz.0.5667/25962:
 #0: ffffffff8dd47de8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
 #0: ffffffff8dd47de8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x824/0xfc0 net/core/rtnetlink.c:6154
 #1: ffffffff8cb33278 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:323 [inline]
 #1: ffffffff8cb33278 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3c0/0x890 kernel/rcu/tree_exp.h:962
1 lock held by syz.4.5666/25964:
 #0: ffffffff8c9ebae8 (sched_core_mutex){+.+.}-{3:3}, at: sched_core_get+0x49/0x1c0 kernel/sched/core.c:399
1 lock held by syz.5.5668/25968:
 #0: ffff888053e85010 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
 #0: ffff888053e85010 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: __sock_release net/socket.c:653 [inline]
 #0: ffff888053e85010 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: sock_close+0x90/0x240 net/socket.c:1399
1 lock held by dhcpcd/25972:
 #0: ffff8880669f0130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1805 [inline]
 #0: ffff8880669f0130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x32/0xce0 net/packet/af_packet.c:3249
1 lock held by dhcpcd/25973:
 #0: ffff88806323a130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1805 [inline]
 #0: ffff88806323a130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x32/0xce0 net/packet/af_packet.c:3249
1 lock held by dhcpcd/25974:
 #0: ffff888057ab4130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1805 [inline]
 #0: ffff888057ab4130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x32/0xce0 net/packet/af_packet.c:3249
1 lock held by dhcpcd/25975:
 #0: ffff888051aba130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1805 [inline]
 #0: ffff888051aba130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x32/0xce0 net/packet/af_packet.c:3249
1 lock held by syz-executor/25979:
 #0: ffffffff8dd47de8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
 #0: ffffffff8dd47de8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x824/0xfc0 net/core/rtnetlink.c:6154
1 lock held by syz-executor/25982:
 #0: ffffffff8dd47de8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
 #0: ffffffff8dd47de8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x824/0xfc0 net/core/rtnetlink.c:6154
1 lock held by syz-executor/25985:
 #0: ffffffff8dd47de8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
 #0: ffffffff8dd47de8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x824/0xfc0 net/core/rtnetlink.c:6154
1 lock held by syz-executor/25990:
 #0: ffffffff8dd47de8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
 #0: ffffffff8dd47de8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x824/0xfc0 net/core/rtnetlink.c:6154
1 lock held by syz-executor/25993:
 #0: ffffffff8dd47de8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
 #0: ffffffff8dd47de8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x824/0xfc0 net/core/rtnetlink.c:6154
1 lock held by dhcpcd/25995:
 #0: ffff88806730e130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1805 [inline]
 #0: ffff88806730e130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x32/0xce0 net/packet/af_packet.c:3249
1 lock held by dhcpcd/25996:
 #0: ffff8880675da130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1805 [inline]
 #0: ffff8880675da130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x32/0xce0 net/packet/af_packet.c:3249
1 lock held by dhcpcd/25997:
 #0: ffff88807704c130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1805 [inline]
 #0: ffff88807704c130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x32/0xce0 net/packet/af_packet.c:3249
1 lock held by dhcpcd/25998:
 #0: ffff88802859e130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1805 [inline]
 #0: ffff88802859e130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x32/0xce0 net/packet/af_packet.c:3249
1 lock held by dhcpcd/25999:
 #0: ffff88801db94130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1805 [inline]
 #0: ffff88801db94130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x32/0xce0 net/packet/af_packet.c:3249
1 lock held by dhcpcd/26000:
 #0: ffff88807871e130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1805 [inline]
 #0: ffff88807871e130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x32/0xce0 net/packet/af_packet.c:3249
1 lock held by dhcpcd/26001:
 #0: ffff888053a7a130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1805 [inline]
 #0: ffff888053a7a130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x32/0xce0 net/packet/af_packet.c:3249
1 lock held by dhcpcd/26002:
 #0: ffff8880681ea130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1805 [inline]
 #0: ffff8880681ea130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x32/0xce0 net/packet/af_packet.c:3249
1 lock held by dhcpcd/26003:
 #0: ffff88801e6d6130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1805 [inline]
 #0: ffff88801e6d6130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x32/0xce0 net/packet/af_packet.c:3249
1 lock held by dhcpcd/26004:
 #0: ffff888065d7e130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1805 [inline]
 #0: ffff888065d7e130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x32/0xce0 net/packet/af_packet.c:3249
1 lock held by dhcpcd/26005:
 #0: ffff88805c74e130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1805 [inline]
 #0: ffff88805c74e130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x32/0xce0 net/packet/af_packet.c:3249
1 lock held by dhcpcd/26006:
 #0: ffff88808c724130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1805 [inline]
 #0: ffff88808c724130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x32/0xce0 net/packet/af_packet.c:3249
1 lock held by syz-executor/26010:
 #0: ffffffff8dd47de8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
 #0: ffffffff8dd47de8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x824/0xfc0 net/core/rtnetlink.c:6154
1 lock held by syz-executor/26013:
 #0: ffffffff8dd47de8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
 #0: ffffffff8dd47de8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x824/0xfc0 net/core/rtnetlink.c:6154
1 lock held by syz-executor/26015:
 #0: ffffffff8dd47de8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
 #0: ffffffff8dd47de8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x824/0xfc0 net/core/rtnetlink.c:6154
1 lock held by syz-executor/26019:
 #0: ffffffff8dd47de8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
 #0: ffffffff8dd47de8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x824/0xfc0 net/core/rtnetlink.c:6154
1 lock held by syz-executor/26022:
 #0: ffffffff8dd47de8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
 #0: ffffffff8dd47de8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x824/0xfc0 net/core/rtnetlink.c:6154
1 lock held by syz-executor/26027:
 #0: ffffffff8dd47de8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
 #0: ffffffff8dd47de8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x824/0xfc0 net/core/rtnetlink.c:6154
1 lock held by syz-executor/26030:
 #0: ffffffff8dd47de8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
 #0: ffffffff8dd47de8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x824/0xfc0 net/core/rtnetlink.c:6154
1 lock held by syz-executor/26033:
 #0: ffffffff8dd47de8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
 #0: ffffffff8dd47de8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x824/0xfc0 net/core/rtnetlink.c:6154
1 lock held by syz-executor/26036:
 #0: ffffffff8dd47de8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
 #0: ffffffff8dd47de8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x824/0xfc0 net/core/rtnetlink.c:6154
1 lock held by syz-executor/26039:
 #0: ffffffff8dd47de8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
 #0: ffffffff8dd47de8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x824/0xfc0 net/core/rtnetlink.c:6154

=============================================

NMI backtrace for cpu 0
CPU: 0 PID: 28 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3e6/0x460 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x1d4/0x450 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
 watchdog+0xeee/0xf30 kernel/hung_task.c:377
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 57 Comm: kworker/u4:4 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:arch_static_branch arch/x86/include/asm/jump_label.h:27 [inline]
RIP: 0010:static_key_false include/linux/jump_label.h:207 [inline]
RIP: 0010:native_write_msr arch/x86/include/asm/msr.h:147 [inline]
RIP: 0010:wrmsrl arch/x86/include/asm/msr.h:262 [inline]
RIP: 0010:native_x2apic_icr_write arch/x86/include/asm/apic.h:239 [inline]
RIP: 0010:__x2apic_send_IPI_dest arch/x86/kernel/apic/x2apic_phys.c:126 [inline]
RIP: 0010:x2apic_send_IPI+0x70/0xd0 arch/x86/kernel/apic/x2apic_phys.c:48
Code: f0 48 c1 e8 03 42 0f b6 04 20 84 c0 75 3b 41 0f b7 16 0f ae f0 0f ae e8 83 fb 02 b8 00 04 00 00 0f 45 c3 b9 30 08 00 00 0f 30 <66> 90 5b 41 5c 41 5e 41 5f 5d c3 89 fe 89 fd 48 c7 c7 c0 90 99 8c
RSP: 0018:ffffc90001587710 EFLAGS: 00000206
RAX: 00000000000000fb RBX: 00000000000000fb RCX: 0000000000000830
RDX: 0000000000000000 RSI: 00000000000000fb RDI: 0000000000000000
RBP: ffffc900015877f0 R08: ffff8880b8f3bbd7 R09: 1ffff110171e777a
R10: dffffc0000000000 R11: ffffed10171e777b R12: dffffc0000000000
R13: 1ffff920002b0eec R14: ffff8880b8e219b0 R15: ffffffff8c652980
FS:  0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000056450940df70 CR3: 000000000c88e000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 arch_send_call_function_single_ipi arch/x86/include/asm/smp.h:109 [inline]
 send_call_function_single_ipi+0x155/0x200 kernel/sched/core.c:3786
 smp_call_function_many_cond+0xb5f/0x1290 kernel/smp.c:978
 on_each_cpu_cond_mask+0x3b/0x80 kernel/smp.c:1165
 on_each_cpu include/linux/smp.h:71 [inline]
 text_poke_sync arch/x86/kernel/alternative.c:1574 [inline]
 text_poke_bp_batch+0x5ae/0x850 arch/x86/kernel/alternative.c:1836
 text_poke_flush arch/x86/kernel/alternative.c:1965 [inline]
 text_poke_finish+0x16/0x30 arch/x86/kernel/alternative.c:1972
 arch_jump_label_transform_apply+0x13/0x20 arch/x86/kernel/jump_label.c:146
 static_key_enable_cpuslocked+0x11f/0x240 kernel/jump_label.c:207
 static_key_enable+0x16/0x20 kernel/jump_label.c:220
 toggle_allocation_gate+0xba/0x470 mm/kfence/core.c:821
 process_one_work+0x8a2/0x1160 kernel/workqueue.c:2292
 worker_thread+0xaa2/0x1270 kernel/workqueue.c:2439
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/04/13 09:20 linux-6.1.y 8e8fc038cad5 38c8e246 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in __lru_add_drain_all
2026/03/10 22:54 linux-6.1.y f2ddafa93a25 4683d576 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in __lru_add_drain_all
* Struck through repros no longer work on HEAD.