INFO: task syz.0.1724:10716 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.0.1724 state:D stack:25256 pid:10716 ppid:5783 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x15ae/0x4660 kernel/sched/core.c:6701 schedule+0xbd/0x170 kernel/sched/core.c:6775 perf_pending_task_sync kernel/events/core.c:5244 [inline] _free_event+0x176/0xfb0 kernel/events/core.c:5250 put_event kernel/events/core.c:5378 [inline] perf_event_release_kernel+0x7c8/0x850 kernel/events/core.c:5503 perf_release+0x3b/0x40 kernel/events/core.c:5513 __fput+0x221/0x940 fs/file_table.c:418 task_work_run+0x1d4/0x260 kernel/task_work.c:245 exit_task_work include/linux/task_work.h:43 [inline] do_exit+0x986/0x2530 kernel/exit.c:890 do_group_exit+0x22d/0x2f0 kernel/exit.c:1032 get_signal+0x12a6/0x1390 kernel/signal.c:2911 arch_do_signal_or_restart+0xc2/0x7b0 arch/x86/kernel/signal.c:310 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline] syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302 do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fc75a79e159 RSP: 002b:00007fc75b63c028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: 0000000000000012 RBX: 00007fc75aa25fa0 RCX: 00007fc75a79e159 RDX: 0000000000000012 RSI: 0000200000000080 RDI: 000000000000000b RBP: 00007fc75a835024 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fc75aa26038 R14: 00007fc75aa25fa0 R15: 00007ffc5a99d1e8 Showing all locks held in the system: 2 locks held by rcu_tasks_trace/15: #0: ffffffff8d132ad0 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0xb11/0xdf0 kernel/rcu/tasks.h:607 #1: ffffffff8d137778 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:324 [inline] #1: ffffffff8d137778 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3da/0x880 kernel/rcu/tree_exp.h:1004 1 lock held by khungtaskd/29: #0: ffffffff8d131da0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline] #0: ffffffff8d131da0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline] #0: ffffffff8d131da0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6633 3 locks held by kworker/u4:7/2881: #0: ffff888017c71938 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline] #0: ffff888017c71938 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734 #1: ffffc9000b9b7d00 ((work_completion)(&map->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline] #1: ffffc9000b9b7d00 ((work_completion)(&map->work)){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734 #2: ffffffff8d137778 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:324 [inline] #2: ffffffff8d137778 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3da/0x880 kernel/rcu/tree_exp.h:1004 2 locks held by kworker/u4:8/3493: #0: ffff888017c71938 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline] #0: ffff888017c71938 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734 #1: ffffc9000cc77d00 ((work_completion)(&map->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline] #1: ffffc9000cc77d00 ((work_completion)(&map->work)){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734 2 locks held by getty/5533: #0: ffff8880311720a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x428/0x1370 drivers/tty/n_tty.c:2217 2 locks held by kworker/1:5/5817: #0: ffff888017c72d38 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline] #0: ffff888017c72d38 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734 #1: ffffc9000498fd00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline] #1: ffffc9000498fd00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734 2 locks held by kworker/u4:11/11076: #0: ffff888017c71938 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline] #0: ffff888017c71938 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734 #1: ffffc900045efd00 ((work_completion)(&map->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline] #1: ffffc900045efd00 ((work_completion)(&map->work)){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734 1 lock held by syz.1.2138/11900: #0: ffffffff8d188088 (event_mutex){+.+.}-{3:3}, at: perf_trace_destroy+0x2e/0x140 kernel/trace/trace_event_perf.c:239 1 lock held by syz.2.2139/11902: #0: ffff8880784fd620 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:804 [inline] #0: ffff8880784fd620 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: __sock_release net/socket.c:658 [inline] #0: ffff8880784fd620 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: sock_close+0x82/0x210 net/socket.c:1421 1 lock held by syz.4.2141/11907: #0: ffffffff8d188088 (event_mutex){+.+.}-{3:3}, at: perf_trace_destroy+0x2e/0x140 kernel/trace/trace_event_perf.c:239 6 locks held by syz.4.2141/11908: #0: ffff88802bce0848 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2a3/0x330 fs/file.c:1040 #1: ffff88802efae418 (sb_writers#10){.+.+}-{0:0}, at: vfs_write+0x21e/0x9a0 fs/read_write.c:580 #2: ffff88805d8abc88 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1dc/0x520 fs/kernfs/file.c:343 #3: ffffffff8d15b9e8 (cgroup_mutex){+.+.}-{3:3}, at: cgroup_lock include/linux/cgroup.h:369 [inline] #3: ffffffff8d15b9e8 (cgroup_mutex){+.+.}-{3:3}, at: cgroup_kn_lock_live+0xe9/0x230 kernel/cgroup/cgroup.c:1677 #4: ffffffff8cfcd110 (cpu_hotplug_lock){++++}-{0:0}, at: cgroup_attach_lock kernel/cgroup/cgroup.c:2414 [inline] #4: ffffffff8cfcd110 (cpu_hotplug_lock){++++}-{0:0}, at: cgroup_procs_write_start+0x18a/0x610 kernel/cgroup/cgroup.c:2919 #5: ffffffff8d15bbd0 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: cgroup_attach_lock kernel/cgroup/cgroup.c:2416 [inline] #5: ffffffff8d15bbd0 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: cgroup_procs_write_start+0x1a0/0x610 kernel/cgroup/cgroup.c:2919 4 locks held by syz.4.2141/11911: #0: ffff88802e2c9c48 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2a3/0x330 fs/file.c:1040 #1: ffff88802efae418 (sb_writers#10){.+.+}-{0:0}, at: vfs_write+0x21e/0x9a0 fs/read_write.c:580 #2: ffff88807bb31888 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1dc/0x520 fs/kernfs/file.c:343 #3: ffffffff8d15b9e8 (cgroup_mutex){+.+.}-{3:3}, at: cgroup_lock include/linux/cgroup.h:369 [inline] #3: ffffffff8d15b9e8 (cgroup_mutex){+.+.}-{3:3}, at: cgroup_lock_and_drain_offline+0x8f/0x4a0 kernel/cgroup/cgroup.c:3094 1 lock held by syz.3.2142/11909: #0: ffff8880785abe20 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:804 [inline] #0: ffff8880785abe20 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: __sock_release net/socket.c:658 [inline] #0: ffff8880785abe20 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: sock_close+0x82/0x210 net/socket.c:1421 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 29 Comm: khungtaskd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Call Trace: dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106 nmi_cpu_backtrace+0x3a6/0x3e0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x2f0 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline] watchdog+0xf59/0xfa0 kernel/hung_task.c:379 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 5784 Comm: syz-executor Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 RIP: 0010:queued_read_lock include/asm-generic/qrwlock.h:83 [inline] RIP: 0010:do_raw_read_lock+0x46/0x90 kernel/locking/spinlock_debug.c:161 Code: fc ff df 0f b6 04 08 84 c0 75 46 41 81 3e ed 1e af de 75 21 48 89 df be 04 00 00 00 e8 f3 13 76 00 b8 00 02 00 00 f0 0f c1 03 ff 01 00 00 75 15 5b 41 5e c3 48 89 df 48 c7 c6 80 22 cb 8a e8 RSP: 0018:ffffc9000473fbd0 EFLAGS: 00000206 RAX: 0000000000000000 RBX: ffffffff8ce0a040 RCX: ffffffff8169de2d RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffffff8ce0a040 RBP: dffffc0000000000 R08: ffffffff8ce0a043 R09: 1ffffffff19c1408 R10: dffffc0000000000 R11: fffffbfff19c1409 R12: ffff88801b7eb590 R13: ffffc9000473fcc8 R14: ffffffff8ce0a048 R15: ffff88801b7ea718 FS: 000055557bd7f500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000560758832a38 CR3: 0000000061fd9000 CR4: 00000000003506e0 Call Trace: do_wait+0x295/0xab0 kernel/exit.c:1615 kernel_wait4+0x22f/0x2b0 kernel/exit.c:1788 __do_sys_wait4 kernel/exit.c:1816 [inline] __se_sys_wait4 kernel/exit.c:1812 [inline] __x64_sys_wait4+0x167/0x240 kernel/exit.c:1812 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f8ceb95e98e Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08 RSP: 002b:00007fff67d597f8 EFLAGS: 00000246 ORIG_RAX: 000000000000003d RAX: ffffffffffffffda RBX: 000055557bd7f500 RCX: 00007f8ceb95e98e RDX: 0000000040000001 RSI: 00007fff67d5989c RDI: ffffffffffffffff RBP: 00007fff67d5989c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000226 R13: 0000000000000064 R14: 00000000000bc989 R15: 00007fff67d598f0