INFO: task rcu_tasks_kthre:12 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:rcu_tasks_kthre state:D stack:27888 pid:12 ppid:2 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5257 [inline]
__schedule+0x1089/0x4140 kernel/sched/core.c:6584
schedule+0xb9/0x180 kernel/sched/core.c:6660
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+0x2c2/0x590 kernel/sched/completion.c:138
__synchronize_srcu+0x2b3/0x350 kernel/rcu/srcutree.c:1243
rcu_tasks_wait_gp+0x49d/0xb00 kernel/rcu/tasks.h:719
rcu_tasks_one_gp+0xb1c/0xce0 kernel/rcu/tasks.h:560
rcu_tasks_kthread+0x6e/0x90 kernel/rcu/tasks.h:588
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
#0: ffffffff8db2e3f0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xce0 kernel/rcu/tasks.h:543
1 lock held by rcu_tasks_trace/13:
#0: ffffffff8db2ec30 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xce0 kernel/rcu/tasks.h:543
1 lock held by khungtaskd/28:
#0: ffffffff8db2daa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
#0: ffffffff8db2daa0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
#0: ffffffff8db2daa0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6669
2 locks held by getty/4031:
#0: ffff88814c814098 (&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+0x430/0x1400 drivers/tty/n_tty.c:2198
3 locks held by kworker/u4:13/5206:
#0: ffff888018479138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#1: ffffc90003397d00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#2: ffffffff8ed6b9e8 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xa/0x50 net/core/link_watch.c:263
3 locks held by kworker/0:3/17974:
#0: ffff88814c3d3138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#1: ffffc90003d3fd00 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#2: ffffffff8ed6b9e8 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_verify_work+0x15/0x30 net/ipv6/addrconf.c:4687
2 locks held by kworker/1:2/18884:
#0: ffff888018472138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#1: ffffc90005c17d00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
3 locks held by kworker/u4:42/19475:
#0: ffff888018479138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#1: ffffc9000c767d00 ((work_completion)(&map->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#2: ffffffff8db337b8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:323 [inline]
#2: ffffffff8db337b8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3c0/0x890 kernel/rcu/tree_exp.h:962
1 lock held by syz.4.3450/19491:
#0: ffffffff8ed6b9e8 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:698 [inline]
#0: ffffffff8ed6b9e8 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3d/0x1b0 drivers/net/tun.c:3506
1 lock held by syz.6.3452/19493:
#0: ffffffff8ed6b9e8 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:698 [inline]
#0: ffffffff8ed6b9e8 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3d/0x1b0 drivers/net/tun.c:3506
2 locks held by syz.6.3452/19495:
2 locks held by syz.5.3454/19506:
#0: ffffffff8ed516e8 (br_ioctl_mutex){+.+.}-{3:3}, at: br_ioctl_call net/socket.c:1174 [inline]
#0: ffffffff8ed516e8 (br_ioctl_mutex){+.+.}-{3:3}, at: sock_ioctl+0x434/0x700 net/socket.c:1275
#1: ffffffff8ed6b9e8 (rtnl_mutex){+.+.}-{3:3}, at: br_ioctl_stub+0x1ac/0xcf0 net/bridge/br_ioctl.c:418
1 lock held by syz.5.3454/19511:
#0: ffffffff8ed516e8 (br_ioctl_mutex){+.+.}-{3:3}, at: br_ioctl_call net/socket.c:1174 [inline]
#0: ffffffff8ed516e8 (br_ioctl_mutex){+.+.}-{3:3}, at: sock_ioctl+0x434/0x700 net/socket.c:1275
1 lock held by syz.0.3453/19505:
#0: ffffffff8db82da8 (event_mutex){+.+.}-{3:3}, at: perf_trace_destroy+0x2a/0x140 kernel/trace/trace_event_perf.c:239
=============================================
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 11/06/2026
Call Trace:
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+0xf0e/0xf50 kernel/hung_task.c:377
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 3623 Comm: syslogd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/06/2026
RIP: 0010:__debug_check_no_obj_freed lib/debugobjects.c:1035 [inline]
RIP: 0010:debug_check_no_obj_freed+0x12e/0x520 lib/debugobjects.c:1075
Code: ef e8 46 0d 00 00 48 ba 00 00 00 00 00 fc ff df ff c3 4c 89 f5 4d 85 f6 0f 84 2e 03 00 00 49 89 ec 49 c1 ec 03 41 80 3c 14 00 <74> 12 48 89 ef e8 98 54 be fd 48 ba 00 00 00 00 00 fc ff df 4c 8b
RSP: 0018:ffffc90003297918 EFLAGS: 00000046
RAX: 1ffffffff2fe8146 RBX: 0000000000000000 RCX: 0000000000000001
RDX: dffffc0000000000 RSI: 0000000000000004 RDI: ffffc90003297800
RBP: ffff888056aa06c8 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52000652f00 R12: 1ffff1100ad540d9
R13: ffff88802c7105f0 R14: ffff88802c710000 R15: 0000000000000000
FS: 00007f7fb1505c80(0000) GS:ffff8880b8d00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555758de5088 CR3: 000000007e45e000 CR4: 00000000003506e0
DR0: 0000200000000740 DR1: 0000200000000740 DR2: 0000200000000740
DR3: 00002000000002c0 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
slab_free_hook mm/slub.c:1710 [inline]
slab_free_freelist_hook+0xd2/0x1b0 mm/slub.c:1761
slab_free mm/slub.c:3694 [inline]
kmem_cache_free+0xf7/0x2a0 mm/slub.c:3716
__unix_dgram_recvmsg+0xa04/0xda0 net/unix/af_unix.c:2543
sock_recvmsg_nosec net/socket.c:1023 [inline]
sock_recvmsg net/socket.c:1041 [inline]
sock_read_iter+0x2da/0x3a0 net/socket.c:1122
call_read_iter include/linux/fs.h:2265 [inline]
new_sync_read fs/read_write.c:389 [inline]
vfs_read+0x471/0x960 fs/read_write.c:470
ksys_read+0x14d/0x260 fs/read_write.c:613
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: 0033:0x7f7fb1655407
Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007ffd964b01f0 EFLAGS: 00000202 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f7fb1505c80 RCX: 00007f7fb1655407
RDX: 00000000000000ff RSI: 000055632f473950 RDI: 0000000000000000
RBP: 000055632f473910 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 000055632f47398a
R13: 0000000000000000 R14: 000055632f473950 R15: 000055631ab3ad98