INFO: task syz.1.850:8145 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.1.850 state:D stack:23592 pid:8145 ppid:5801 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x1553/0x45a0 kernel/sched/core.c:6700 schedule+0xbd/0x170 kernel/sched/core.c:6774 perf_pending_task_sync kernel/events/core.c:5242 [inline] _free_event+0x174/0xf30 kernel/events/core.c:5248 put_event kernel/events/core.c:5376 [inline] perf_event_release_kernel+0x842/0x8d0 kernel/events/core.c:5501 perf_release+0x3b/0x40 kernel/events/core.c:5511 __fput+0x234/0x970 fs/file_table.c:384 task_work_run+0x1d4/0x260 kernel/task_work.c:245 get_signal+0x1235/0x13f0 kernel/signal.c:2678 arch_do_signal_or_restart+0xc2/0x800 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+0x61/0xa0 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f11ca79aeb9 RSP: 002b:00007f11cb696fd8 EFLAGS: 00000206 ORIG_RAX: 0000000000000038 RAX: fffffffffffffffc RBX: 00007f11caa15fa0 RCX: 00007f11ca79aeb9 RDX: 0000000000000000 RSI: 000000000003fff0 RDI: 00000000630c1000 RBP: 00007f11ca808c1f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 00007f11caa16038 R14: 00007f11caa15fa0 R15: 00007fff8dec9538 Showing all locks held in the system: 2 locks held by kworker/1:1/27: 1 lock held by khungtaskd/29: #0: ffffffff8d131fe0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline] #0: ffffffff8d131fe0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline] #0: ffffffff8d131fe0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6633 2 locks held by kworker/u4:7/3443: 2 locks held by getty/5522: #0: ffff88814c89f0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000328b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x433/0x1390 drivers/tty/n_tty.c:2217 2 locks held by syz.8.1295/10206: #0: ffffffff8e3bfe08 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:698 [inline] #0: ffffffff8e3bfe08 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x41/0x1c0 drivers/net/tun.c:3511 #1: ffffffff8d1379b8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:292 [inline] #1: ffffffff8d1379b8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x306/0x880 kernel/rcu/tree_exp.h:1004 1 lock held by syz.7.1299/10242: #0: ffffffff8d192168 (bpf_event_mutex){+.+.}-{3:3}, at: perf_event_detach_bpf_prog+0x8b/0x310 kernel/trace/bpf_trace.c:2215 1 lock held by syz.7.1299/10245: #0: ffffffff8e3bfe08 (rtnl_mutex){+.+.}-{3:3}, at: ipv6_route_ioctl+0x322/0x500 net/ipv6/route.c:4520 1 lock held by syz.9.1301/10243: #0: ffffffff8d192168 (bpf_event_mutex){+.+.}-{3:3}, at: perf_event_detach_bpf_prog+0x8b/0x310 kernel/trace/bpf_trace.c:2215 1 lock held by syz.9.1301/10247: #0: ffffffff8e3bfe08 (rtnl_mutex){+.+.}-{3:3}, at: dev_ioctl+0x83c/0x1140 net/core/dev_ioctl.c:794 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 29 Comm: khungtaskd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 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+0xf3d/0xf80 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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 5790 Comm: syz-executor Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:memset_orig+0x7b/0xac arch/x86/lib/memset_64.S:94 Code: 38 48 8d 7f 40 75 d8 0f 1f 84 00 00 00 00 00 89 d1 83 e1 38 74 14 c1 e9 03 66 0f 1f 44 00 00 ff c9 48 89 07 48 8d 7f 08 75 f5 <83> e2 07 74 0a ff ca 88 07 48 8d 7f 01 75 f6 4c 89 d0 c3 48 83 fa RSP: 0018:ffffc900001177b8 EFLAGS: 00000046 RAX: 0000000000000000 RBX: ffffc90000117840 RCX: 0000000000000000 RDX: 0000000000000100 RSI: 0000000000000000 RDI: ffffc90000117940 RBP: ffffc900001179f0 R08: ffffc9000011793f R09: 0000000000000000 R10: ffffc90000117840 R11: fffff52000022f28 R12: dffffc0000000000 R13: ffff8880b8e367e0 R14: 0000000000000000 R15: 1ffff92000022f00 FS: 0000555572440500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000559bf54d9138 CR3: 0000000024922000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: ___perf_sw_event+0xf3/0x730 kernel/events/core.c:9960 __perf_sw_event_sched include/linux/perf_event.h:1457 [inline] perf_event_task_sched_out include/linux/perf_event.h:1490 [inline] prepare_task_switch kernel/sched/core.c:5185 [inline] context_switch kernel/sched/core.c:5328 [inline] __schedule+0x233e/0x45a0 kernel/sched/core.c:6700 schedule+0xbd/0x170 kernel/sched/core.c:6774 do_nanosleep+0x1ad/0x600 kernel/time/hrtimer.c:2091 hrtimer_nanosleep+0x175/0x370 kernel/time/hrtimer.c:2139 __do_sys_clock_nanosleep kernel/time/posix-timers.c:1397 [inline] __se_sys_clock_nanosleep+0x30f/0x3a0 kernel/time/posix-timers.c:1374 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fba88f560d7 Code: 48 89 fa 4c 89 df e8 a8 56 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:00007fff775d4480 EFLAGS: 00000202 ORIG_RAX: 00000000000000e6 RAX: ffffffffffffffda RBX: 0000555572440500 RCX: 00007fba88f560d7 RDX: 00007fff775d44c0 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007fff775d49a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000004 R13: 00007fff775d44fc R14: 00007fff775d4590 R15: 0000000000000000