INFO: task syz.3.165:6482 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.3.165 state:D stack:26920 pid:6482 tgid:6482 ppid:5863 task_flags:0x400040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] schedule+0x165/0x360 kernel/sched/core.c:7058 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7115 __mutex_lock_common kernel/locking/mutex.c:676 [inline] __mutex_lock+0x7e6/0x1350 kernel/locking/mutex.c:760 pipe_release+0x48/0x330 fs/pipe.c:727 __fput+0x44c/0xa70 fs/file_table.c:468 task_work_run+0x1d1/0x260 kernel/task_work.c:227 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop+0xec/0x110 kernel/entry/common.c:43 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f128b78eec9 RSP: 002b:00007ffcdff1c4d8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00007f128b9e7da0 RCX: 00007f128b78eec9 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 00007f128b9e7da0 R08: 0000000000003c2c R09: 00000007dff1c7cf R10: 00007f128b9e7cb0 R11: 0000000000000246 R12: 000000000001d785 R13: 00007ffcdff1c5d0 R14: ffffffffffffffff R15: 00007ffcdff1c5f0 Showing all locks held in the system: 3 locks held by kworker/1:0/24: 1 lock held by khungtaskd/31: #0: ffffffff8e13a0e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e13a0e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8e13a0e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 1 lock held by udevd/5234: 1 lock held by dhcpcd/5528: 2 locks held by getty/5625: #0: ffff88814d0290a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222 1 lock held by dhcpcd/5664: 1 lock held by dhcpcd/5668: 1 lock held by syz-executor/5861: 1 lock held by syz-executor/5862: 1 lock held by syz-executor/5865: 1 lock held by udevd/5919: 1 lock held by udevd/5939: 1 lock held by udevd/6437: 1 lock held by syz.3.165/6482: #0: ffff888058868868 (&pipe->mutex){+.+.}-{4:4}, at: pipe_release+0x48/0x330 fs/pipe.c:727 1 lock held by syz.3.165/6484: #0: ffff888058868868 (&pipe->mutex){+.+.}-{4:4}, at: splice_file_to_pipe+0x2e/0x440 fs/splice.c:1289 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:328 [inline] watchdog+0xf93/0xfe0 kernel/hung_task.c:491 kthread+0x70e/0x8a0 kernel/kthread.c:463 ret_from_fork+0x439/0x7d0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 101 PID: 5528 Comm: dhcpcd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:group_send_sig_info+0x185/0x260 kernel/signal.c:1418 Code: 48 c7 c2 c0 c7 89 8b e8 99 95 16 00 48 c7 c7 e0 a0 13 8e 4c 89 e6 e8 7a 7b 16 00 e8 05 27 20 00 31 ff 44 89 ee e8 db be 38 00 <45> 85 ed 74 2f e8 91 ba 38 00 65 48 8b 05 e9 7b 17 11 48 3b 44 24 RSP: 0018:ffffc90000a08e58 EFLAGS: 00000006 RAX: ffffffff8186f425 RBX: ffff88802eac5a00 RCX: 0000000000010000 RDX: ffff88802eac5a00 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000001 R08: 0000000000000000 R09: ffffffff8186f2dd R10: dffffc0000000000 R11: ffffffff81cbfb20 R12: ffffffff8186f2dd R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000011 FS: 00007f33d529c740(0000) GS:ffff888125d39000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000564433c8a168 CR3: 0000000033718000 CR4: 00000000003526f0 Call Trace: do_bpf_send_signal+0xa9/0x1c0 kernel/trace/bpf_trace.c:814 irq_work_single+0xe1/0x240 kernel/irq_work.c:221 irq_work_run_list kernel/irq_work.c:252 [inline] irq_work_run+0x155/0x2f0 kernel/irq_work.c:261 __sysvec_irq_work+0xa8/0x3d0 arch/x86/kernel/irq_work.c:22 instr_sysvec_irq_work arch/x86/kernel/irq_work.c:17 [inline] sysvec_irq_work+0x9e/0xc0 arch/x86/kernel/irq_work.c:17 asm_sysvec_irq_work+0x1a/0x20 arch/x86/include/asm/idtentry.h:738 RIP: 0010:arch_static_branch arch/x86/include/asm/jump_label.h:36 [inline] RIP: 0010:native_write_msr arch/x86/include/asm/msr.h:139 [inline] RIP: 0010:wrmsrq arch/x86/include/asm/msr.h:199 [inline] RIP: 0010:native_apic_msr_write+0x39/0x50 arch/x86/include/asm/apic.h:212 Code: 74 2a 83 ff 30 74 25 eb 10 81 ff d0 00 00 00 74 1b 81 ff e0 00 00 00 74 13 c1 ef 04 81 c7 00 08 00 00 89 f9 89 f0 31 d2 0f 30 <66> 90 c3 cc cc cc cc cc f3 0f 1e fa 89 f6 31 d2 e9 12 1f 8f 03 66 RSP: 0018:ffffc90003a3fb08 EFLAGS: 00000246 RAX: 00000000000000f6 RBX: 0000000000000200 RCX: 000000000000083f RDX: 0000000000000000 RSI: 00000000000000f6 RDI: 000000000000083f RBP: ffffc90003a3fbe0 R08: ffffc90003a3fb67 R09: 1ffff92000747f6c R10: dffffc0000000000 R11: fffff52000747f6d R12: ffff8880b8731401 R13: 0000000000000000 R14: 0000000000000000 R15: ffff8880b87314b0 __apic_send_IPI_self arch/x86/include/asm/apic.h:455 [inline] arch_irq_work_raise+0x6d/0x80 arch/x86/kernel/irq_work.c:31 irq_work_raise kernel/irq_work.c:84 [inline] __irq_work_queue_local+0x1d7/0x550 kernel/irq_work.c:112 irq_work_queue+0x99/0x140 kernel/irq_work.c:124 bpf_send_signal_common+0x3b4/0x540 kernel/trace/bpf_trace.c:872 ____bpf_send_signal kernel/trace/bpf_trace.c:881 [inline] bpf_send_signal+0x1d/0x30 kernel/trace/bpf_trace.c:879 bpf_prog_7ba5217f62dcd359+0x41/0x49 bpf_dispatcher_nop_func include/linux/bpf.h:1335 [inline] __bpf_prog_run include/linux/filter.h:718 [inline] bpf_prog_run include/linux/filter.h:725 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2257 [inline] bpf_trace_run2+0x284/0x4b0 kernel/trace/bpf_trace.c:2298 __bpf_trace_sys_enter+0x38/0x60 include/trace/events/syscalls.h:18 __do_trace_sys_enter include/trace/events/syscalls.h:18 [inline] trace_sys_enter+0xb0/0x100 include/trace/events/syscalls.h:18 syscall_trace_enter+0xf9/0x160 kernel/entry/syscall-common.c:53 syscall_enter_from_user_mode_work include/linux/entry-common.h:95 [inline] syscall_enter_from_user_mode include/linux/entry-common.h:125 [inline] do_syscall_64+0xd3/0x3b0 arch/x86/entry/syscall_64.c:90 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f33d52de189 Code: 16 00 00 00 eb de 66 2e 0f 1f 84 00 00 00 00 00 90 90 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 c7 c0 0f 00 00 00 0f 05 <0f> 1f 80 00 00 00 00 48 81 ec d0 00 00 00 49 89 d0 48 85 f6 0f 84 RSP: 002b:00007ffcdf8a8b40 EFLAGS: 00000293 ORIG_RAX: 000000000000000f RAX: ffffffffffffffda RBX: 00007f33d529c740 RCX: 00007f33d52de189 RDX: 00005644060a25e0 RSI: 00007ffcdf8a8c70 RDI: 0000000000000011 RBP: 00007ffcdf8a9410 R08: 0000000000000008 R09: 0000000000000000 R10: 00007ffcdf8a9410 R11: 0000000000000293 R12: 00005644060a25e0 R13: 0000564433ca3df0 R14: 00000000ffffffff R15: 00007ffcdf8a91c0