INFO: task syz.0.5239:25937 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.0.5239 state:D stack:23984 pid:25937 ppid:22456 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5246 [inline] __schedule+0x107f/0x4030 kernel/sched/core.c:6563 schedule+0xb9/0x180 kernel/sched/core.c:6639 perf_pending_task_sync kernel/events/core.c:5041 [inline] _free_event+0x176/0x1050 kernel/events/core.c:5047 put_event kernel/events/core.c:5172 [inline] perf_event_release_kernel+0x7c4/0x850 kernel/events/core.c:5297 perf_release+0x37/0x40 kernel/events/core.c:5307 __fput+0x20a/0x8b0 fs/file_table.c:320 task_work_run+0x1d0/0x260 kernel/task_work.c:203 get_signal+0x118d/0x1340 kernel/signal.c:2661 arch_do_signal_or_restart+0xc4/0x1310 arch/x86/kernel/signal.c:871 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:177 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:213 __syscall_exit_to_user_mode_work kernel/entry/common.c:295 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:306 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f3638f9e559 RSP: 002b:00007f3639e51fd8 EFLAGS: 00000206 ORIG_RAX: 0000000000000038 RAX: fffffffffffffff2 RBX: 00007f3639225fa0 RCX: 00007f3638f9e559 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000001000 RBP: 00007f3639035ab8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 00007f3639226038 R14: 00007f3639225fa0 R15: 00007fff40d7de08 Showing all locks held in the system: 1 lock held by rcu_tasks_kthre/12: #0: ffffffff8d92e230 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xef0 kernel/rcu/tasks.h:517 1 lock held by rcu_tasks_trace/13: #0: ffffffff8d92ea50 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xef0 kernel/rcu/tasks.h:517 1 lock held by khungtaskd/28: #0: ffffffff8d92d8a0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #0: ffffffff8d92d8a0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #0: ffffffff8d92d8a0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6669 2 locks held by getty/4025: #0: ffff88814d4d9098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244 #1: ffffc9000327e2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x41e/0x1360 drivers/tty/n_tty.c:2198 2 locks held by kworker/0:3/4330: #0: ffff888018472138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267 #1: ffffc9000498fd00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267 2 locks held by kworker/u4:31/5590: 1 lock held by syz.2.5882/28537: #0: ffffffff8d982b68 (event_mutex){+.+.}-{3:3}, at: perf_trace_destroy+0x2a/0x140 kernel/trace/trace_event_perf.c:239 2 locks held by syz.4.5884/28545: #0: ffffffff97a8bd88 (&pmus_srcu){....}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #0: ffffffff97a8bd88 (&pmus_srcu){....}-{0:0}, at: srcu_read_lock include/linux/srcu.h:165 [inline] #0: ffffffff97a8bd88 (&pmus_srcu){....}-{0:0}, at: perf_init_event kernel/events/core.c:11674 [inline] #0: ffffffff97a8bd88 (&pmus_srcu){....}-{0:0}, at: perf_event_alloc+0xb28/0x21e0 kernel/events/core.c:12000 #1: ffffffff8d982b68 (event_mutex){+.+.}-{3:3}, at: perf_trace_init+0x4c/0x2d0 kernel/trace/trace_event_perf.c:221 2 locks held by syz.4.5884/28551: 1 lock held by syz.4.5884/28552: #0: ffffffff8d933578 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:323 [inline] #0: ffffffff8d933578 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3c0/0x890 kernel/rcu/tree_exp.h:962 1 lock held by syz.5.5883/28546: #0: ffffffff8d982b68 (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 09/16/2026 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: 4373 Comm: kworker/u4:7 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026 Workqueue: events_unbound nsim_dev_trap_report_work RIP: 0010:kasan_check_range+0x1b0/0x290 mm/kasan/generic.c:-1 Code: f3 4d 01 f3 49 89 df 49 8d 5f 07 4d 85 ff 49 0f 49 df 48 83 e3 f8 49 29 df 74 0e 41 80 3b 00 75 69 49 ff c3 49 ff cf 75 f2 5b <41> 5c 41 5e 41 5f 5d c3 45 84 ff 0f 85 91 00 00 00 41 f7 c7 00 ff RSP: 0018:ffffc90004a6f558 EFLAGS: 00000056 RAX: 0000000000000001 RBX: 0000000000000001 RCX: ffffffff81640f49 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff91934328 RBP: ffffc90004a6f7c8 R08: ffffffff9193432f R09: 1ffffffff2326865 R10: dffffc0000000000 R11: fffffbfff2326866 R12: dffffc0000000001 R13: ffff88801ab96528 R14: 1ffffffff2326865 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff8880b8d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f2e389a7ff8 CR3: 000000005f366000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: instrument_atomic_read include/linux/instrumented.h:72 [inline] _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline] hlock_class kernel/locking/lockdep.c:228 [inline] check_wait_context kernel/locking/lockdep.c:4826 [inline] __lock_acquire+0xa49/0x7ea0 kernel/locking/lockdep.c:5121 lock_acquire+0x1bc/0x4a0 kernel/locking/lockdep.c:5790 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xb0/0x100 kernel/locking/spinlock.c:162 __debug_check_no_obj_freed lib/debugobjects.c:1034 [inline] debug_check_no_obj_freed+0x9a/0x520 lib/debugobjects.c:1075 slab_free_hook mm/slub.c:1704 [inline] slab_free_freelist_hook+0xd2/0x1b0 mm/slub.c:1755 slab_free mm/slub.c:3687 [inline] __kmem_cache_free+0xb6/0x200 mm/slub.c:3700 skb_free_head net/core/skbuff.c:762 [inline] skb_release_data+0x5e9/0x7e0 net/core/skbuff.c:791 skb_release_all net/core/skbuff.c:856 [inline] __kfree_skb net/core/skbuff.c:870 [inline] consume_skb+0xa2/0x100 net/core/skbuff.c:1038 nsim_dev_trap_report drivers/net/netdevsim/dev.c:821 [inline] nsim_dev_trap_report_work+0x71f/0xa80 drivers/net/netdevsim/dev.c:851 process_one_work+0x8ab/0x1160 kernel/workqueue.c:2292 worker_thread+0xaf5/0x12a0 kernel/workqueue.c:2439 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295