INFO: task syz.4.169:5895 blocked for more than 143 seconds. Not tainted 6.11.0-rc2-syzkaller-00302-gcb2e5ee8e7a0 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.4.169 state:D stack:27168 pid:5895 tgid:5895 ppid:5218 flags:0x00000004 Call Trace: context_switch kernel/sched/core.c:5188 [inline] __schedule+0xe37/0x5490 kernel/sched/core.c:6529 __schedule_loop kernel/sched/core.c:6606 [inline] schedule+0xe7/0x350 kernel/sched/core.c:6621 schedule_timeout+0x258/0x2a0 kernel/time/timer.c:2557 do_wait_for_common kernel/sched/completion.c:95 [inline] __wait_for_common+0x3de/0x5f0 kernel/sched/completion.c:116 __vhost_worker_flush+0x1aa/0x1e0 drivers/vhost/vhost.c:288 vhost_worker_flush drivers/vhost/vhost.c:295 [inline] vhost_dev_flush+0xad/0x120 drivers/vhost/vhost.c:305 vhost_net_flush+0x1d/0x1b0 drivers/vhost/net.c:1359 vhost_net_release+0xa9/0x260 drivers/vhost/net.c:1380 __fput+0x408/0xbb0 fs/file_table.c:422 task_work_run+0x14e/0x250 kernel/task_work.c:228 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop kernel/entry/common.c:114 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x27b/0x2a0 kernel/entry/common.c:218 do_syscall_64+0xda/0x250 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f8d64b779f9 RSP: 002b:00007fff0697d6c8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00007f8d64d07a80 RCX: 00007f8d64b779f9 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 00007f8d64d07a80 R08: 0000000000000006 R09: 00007fff0697d9af R10: 00000000005e1938 R11: 0000000000000246 R12: 0000000000028174 R13: 00007fff0697d7c0 R14: 00007fff0697d7e0 R15: ffffffffffffffff Showing all locks held in the system: 3 locks held by kworker/u8:1/12: #0: ffff888015889148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x1277/0x1b40 kernel/workqueue.c:3206 #1: ffffc90000117d80 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x921/0x1b40 kernel/workqueue.c:3207 #2: ffffffff8fa21de8 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0x51/0xc0 net/core/link_watch.c:276 1 lock held by khungtaskd/30: #0: ffffffff8ddb5ca0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:326 [inline] #0: ffffffff8ddb5ca0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #0: ffffffff8ddb5ca0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x75/0x340 kernel/locking/lockdep.c:6626 4 locks held by kworker/u8:8/3614: 2 locks held by getty/4978: #0: ffff88802b51c0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc9000311b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xfc8/0x1490 drivers/tty/n_tty.c:2211 2 locks held by syz.1.456/7118: #0: ffffffff8fa21de8 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:698 [inline] #0: ffffffff8fa21de8 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3e/0x250 drivers/net/tun.c:3510 #1: ffffffff8ddc1438 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock+0x282/0x3b0 kernel/rcu/tree_exp.h:296 2 locks held by syz.3.462/7137: #0: ffffffff8fabf430 (cb_lock){++++}-{3:3}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8fa21de8 (rtnl_mutex){+.+.}-{3:3}, at: nl80211_pre_doit+0xb4/0xb10 net/wireless/nl80211.c:16547 1 lock held by syz.0.464/7139: #0: ffffffff8fa21de8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline] #0: ffffffff8fa21de8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x372/0xea0 net/core/rtnetlink.c:6644 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.11.0-rc2-syzkaller-00302-gcb2e5ee8e7a0 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024 Call Trace: __dump_stack lib/dump_stack.c:93 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:119 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:162 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:223 [inline] watchdog+0xf4e/0x1280 kernel/hung_task.c:379 kthread+0x2c1/0x3a0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline] NMI backtrace for cpu 1 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:106 [inline] NMI backtrace for cpu 1 skipped: idling at acpi_safe_halt+0x1a/0x20 drivers/acpi/processor_idle.c:111