INFO: task kworker/1:1:44 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/1:1 state:D stack:24904 pid:44 tgid:44 ppid:2 task_flags:0x4208060 flags:0x00004000 Workqueue: events p9_write_work Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1190/0x5de0 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] schedule+0xe7/0x3a0 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+0x81b/0x1060 kernel/locking/mutex.c:760 anon_pipe_write+0x15d/0x1a90 fs/pipe.c:458 __kernel_write_iter+0x317/0xb10 fs/read_write.c:619 __kernel_write fs/read_write.c:639 [inline] kernel_write fs/read_write.c:660 [inline] kernel_write+0x1f4/0x6c0 fs/read_write.c:650 p9_fd_write net/9p/trans_fd.c:434 [inline] p9_write_work+0x258/0xc10 net/9p/trans_fd.c:485 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3236 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Showing all locks held in the system: 3 locks held by kworker/0:0/9: #0: ffff88801b878d48 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3211 #1: ffffc900000e7d10 ((work_completion)(&m->wq)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3212 #2: ffff888072c3b868 (&pipe->mutex){+.+.}-{4:4}, at: anon_pipe_write+0x15d/0x1a90 fs/pipe.c:458 3 locks held by kworker/1:0/24: #0: ffff88801b878d48 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3211 #1: ffffc900001e7d10 ((work_completion)(&m->wq)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3212 #2: ffff88805d175068 (&pipe->mutex){+.+.}-{4:4}, at: anon_pipe_write+0x15d/0x1a90 fs/pipe.c:458 1 lock held by khungtaskd/31: #0: ffffffff8e5c1220 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e5c1220 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8e5c1220 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6775 3 locks held by kworker/1:1/44: #0: ffff88801b878d48 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3211 #1: ffffc90000b47d10 ((work_completion)(&m->wq)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3212 #2: ffff888072261468 (&pipe->mutex){+.+.}-{4:4}, at: anon_pipe_write+0x15d/0x1a90 fs/pipe.c:458 3 locks held by kworker/0:2/976: #0: ffff88801b878d48 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3211 #1: ffffc900037cfd10 ((work_completion)(&m->wq)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3212 #2: ffff888070a08868 (&pipe->mutex){+.+.}-{4:4}, at: anon_pipe_write+0x15d/0x1a90 fs/pipe.c:458 3 locks held by kworker/1:2/3202: #0: ffff88801b878d48 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3211 #1: ffffc9000bff7d10 ((work_completion)(&m->wq)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3212 #2: ffff88807215a068 (&pipe->mutex){+.+.}-{4:4}, at: anon_pipe_write+0x15d/0x1a90 fs/pipe.c:458 2 locks held by getty/5613: #0: ffff88814d6fe0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc900036bb2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222 3 locks held by kworker/0:3/5888: #0: ffff88801b878d48 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3211 #1: ffffc900030e7d10 ((work_completion)(&m->wq)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3212 #2: ffff888073986468 (&pipe->mutex){+.+.}-{4:4}, at: anon_pipe_write+0x15d/0x1a90 fs/pipe.c:458 2 locks held by syz.0.16/6472: #0: ffff888072261468 (&pipe->mutex){+.+.}-{4:4}, at: anon_pipe_write+0x15d/0x1a90 fs/pipe.c:458 #1: ffff8880716182e8 (mapping.invalidate_lock#3){.+.+}-{4:4}, at: filemap_invalidate_lock_shared include/linux/fs.h:934 [inline] #1: ffff8880716182e8 (mapping.invalidate_lock#3){.+.+}-{4:4}, at: filemap_fault+0x61d/0x2930 mm/filemap.c:3452 3 locks held by kworker/0:5/6474: #0: ffff88801b878d48 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3211 #1: ffffc90003e3fd10 ((work_completion)(&m->wq)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3212 #2: ffff88803421d468 (&pipe->mutex){+.+.}-{4:4}, at: anon_pipe_write+0x15d/0x1a90 fs/pipe.c:458 2 locks held by syz.1.17/6497: #0: ffff88803421d468 (&pipe->mutex){+.+.}-{4:4}, at: anon_pipe_write+0x15d/0x1a90 fs/pipe.c:458 #1: ffff888059a982e8 (mapping.invalidate_lock#3){.+.+}-{4:4}, at: filemap_invalidate_lock_shared include/linux/fs.h:934 [inline] #1: ffff888059a982e8 (mapping.invalidate_lock#3){.+.+}-{4:4}, at: filemap_fault+0x61d/0x2930 mm/filemap.c:3452 2 locks held by syz.2.20/6524: #0: ffff888070a08868 (&pipe->mutex){+.+.}-{4:4}, at: anon_pipe_write+0x15d/0x1a90 fs/pipe.c:458 #1: ffff888059a98fc8 (mapping.invalidate_lock#3){.+.+}-{4:4}, at: filemap_invalidate_lock_shared include/linux/fs.h:934 [inline] #1: ffff888059a98fc8 (mapping.invalidate_lock#3){.+.+}-{4:4}, at: filemap_fault+0x61d/0x2930 mm/filemap.c:3452 2 locks held by syz.3.21/6553: #0: ffff888073986468 (&pipe->mutex){+.+.}-{4:4}, at: anon_pipe_write+0x15d/0x1a90 fs/pipe.c:458 #1: ffff888059a99638 (mapping.invalidate_lock#3){.+.+}-{4:4}, at: filemap_invalidate_lock_shared include/linux/fs.h:934 [inline] #1: ffff888059a99638 (mapping.invalidate_lock#3){.+.+}-{4:4}, at: filemap_fault+0x61d/0x2930 mm/filemap.c:3452 3 locks held by kworker/0:6/6554: #0: ffff88801b878d48 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3211 #1: ffffc90003d5fd10 ((work_completion)(&m->wq)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3212 #2: ffff888073542c68 (&pipe->mutex){+.+.}-{4:4}, at: anon_pipe_write+0x15d/0x1a90 fs/pipe.c:458 2 locks held by syz.4.22/6583: #0: ffff88807215a068 (&pipe->mutex){+.+.}-{4:4}, at: anon_pipe_write+0x15d/0x1a90 fs/pipe.c:458 #1: ffff888059a99ca8 (mapping.invalidate_lock#3){.+.+}-{4:4}, at: filemap_invalidate_lock_shared include/linux/fs.h:934 [inline] #1: ffff888059a99ca8 (mapping.invalidate_lock#3){.+.+}-{4:4}, at: filemap_fault+0x61d/0x2930 mm/filemap.c:3452 2 locks held by syz.5.23/6612: #0: ffff88805d175068 (&pipe->mutex){+.+.}-{4:4}, at: anon_pipe_write+0x15d/0x1a90 fs/pipe.c:458 #1: ffff888071618fc8 (mapping.invalidate_lock#3){.+.+}-{4:4}, at: filemap_invalidate_lock_shared include/linux/fs.h:934 [inline] #1: ffff888071618fc8 (mapping.invalidate_lock#3){.+.+}-{4:4}, at: filemap_fault+0x61d/0x2930 mm/filemap.c:3452 3 locks held by kworker/0:7/6616: #0: ffff88801b878d48 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3211 #1: ffffc90002ff7d10 ((work_completion)(&m->wq)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3212 #2: ffff88802dc29c68 (&pipe->mutex){+.+.}-{4:4}, at: anon_pipe_write+0x15d/0x1a90 fs/pipe.c:458 2 locks held by syz.6.24/6644: #0: ffff888072c3b868 (&pipe->mutex){+.+.}-{4:4}, at: anon_pipe_write+0x15d/0x1a90 fs/pipe.c:458 #1: ffff888059a9a318 (mapping.invalidate_lock#3){.+.+}-{4:4}, at: filemap_invalidate_lock_shared include/linux/fs.h:934 [inline] #1: ffff888059a9a318 (mapping.invalidate_lock#3){.+.+}-{4:4}, at: filemap_fault+0x61d/0x2930 mm/filemap.c:3452 2 locks held by syz.7.25/6680: #0: ffff88802dc29c68 (&pipe->mutex){+.+.}-{4:4}, at: anon_pipe_write+0x15d/0x1a90 fs/pipe.c:458 #1: ffff888059a9a988 (mapping.invalidate_lock#3){.+.+}-{4:4}, at: filemap_invalidate_lock_shared include/linux/fs.h:934 [inline] #1: ffff888059a9a988 (mapping.invalidate_lock#3){.+.+}-{4:4}, at: filemap_fault+0x61d/0x2930 mm/filemap.c:3452 3 locks held by kworker/0:9/6682: #0: ffff88801b878d48 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3211 #1: ffffc9000425fd10 ((work_completion)(&m->wq)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3212 #2: ffff888073cad868 (&pipe->mutex){+.+.}-{4:4}, at: anon_pipe_write+0x15d/0x1a90 fs/pipe.c:458 2 locks held by syz.8.26/6712: #0: ffff888073542c68 (&pipe->mutex){+.+.}-{4:4}, at: anon_pipe_write+0x15d/0x1a90 fs/pipe.c:458 #1: ffff888059a9aff8 (mapping.invalidate_lock#3){.+.+}-{4:4}, at: filemap_invalidate_lock_shared include/linux/fs.h:934 [inline] #1: ffff888059a9aff8 (mapping.invalidate_lock#3){.+.+}-{4:4}, at: filemap_fault+0x61d/0x2930 mm/filemap.c:3452 2 locks held by syz.9.28/6745: #0: ffff888073cad868 (&pipe->mutex){+.+.}-{4:4}, at: anon_pipe_write+0x15d/0x1a90 fs/pipe.c:458 #1: ffff888059a9bcd8 (mapping.invalidate_lock#3){.+.+}-{4:4}, at: filemap_invalidate_lock_shared include/linux/fs.h:934 [inline] #1: ffff888059a9bcd8 (mapping.invalidate_lock#3){.+.+}-{4:4}, at: filemap_fault+0x61d/0x2930 mm/filemap.c:3452 ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x29c/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+0xf0e/0x1260 kernel/hung_task.c:491 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82 Code: 4c 62 02 c3 cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d d3 52 16 00 fb f4 4c 09 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 RSP: 0018:ffffffff8e207e08 EFLAGS: 000002c2 RAX: 00000000001c9123 RBX: 0000000000000000 RCX: ffffffff8b93bc29 RDX: 0000000000000000 RSI: ffffffff8de50220 RDI: ffffffff8c162900 RBP: fffffbfff1c52ef8 R08: 0000000000000001 R09: ffffed1017086655 R10: ffff8880b84332ab R11: 0000000000000000 R12: 0000000000000000 R13: ffffffff8e2977c0 R14: ffffffff90ab4c90 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881246b9000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055f1509a3fc8 CR3: 0000000032d90000 CR4: 00000000003526f0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:757 default_idle_call+0x6d/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:190 [inline] do_idle+0x391/0x510 kernel/sched/idle.c:330 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:428 rest_init+0x16b/0x2b0 init/main.c:744 start_kernel+0x3ee/0x4d0 init/main.c:1097 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:307 x86_64_start_kernel+0x130/0x190 arch/x86/kernel/head64.c:288 common_startup_64+0x13e/0x148