INFO: task syz-executor.4:21227 blocked for more than 140 seconds. Not tainted 4.19.48 #20 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D28224 21227 7608 0x00000004 Call Trace: context_switch kernel/sched/core.c:2826 [inline] __schedule+0x80d/0x1c70 kernel/sched/core.c:3474 schedule+0x92/0x1c0 kernel/sched/core.c:3518 schedule_timeout+0x8c8/0xfc0 kernel/time/timer.c:1780 do_wait_for_common kernel/sched/completion.c:83 [inline] __wait_for_common kernel/sched/completion.c:104 [inline] wait_for_common kernel/sched/completion.c:115 [inline] wait_for_completion+0x29c/0x440 kernel/sched/completion.c:136 __flush_work+0x49f/0x880 kernel/workqueue.c:2920 __cancel_work_timer+0x3bf/0x520 kernel/workqueue.c:3007 cancel_work_sync+0x18/0x20 kernel/workqueue.c:3043 p9_conn_destroy net/9p/trans_fd.c:864 [inline] p9_fd_close+0x2b7/0x470 net/9p/trans_fd.c:891 p9_client_create+0x9ba/0x12d0 net/9p/client.c:1086 v9fs_session_init+0x1e7/0x18c0 fs/9p/v9fs.c:421 v9fs_mount+0x7d/0x920 fs/9p/vfs_super.c:135 mount_fs+0xa8/0x32b fs/super.c:1261 vfs_kern_mount.part.0+0x6f/0x410 fs/namespace.c:961 vfs_kern_mount fs/namespace.c:951 [inline] do_new_mount fs/namespace.c:2469 [inline] do_mount+0x53e/0x2bc0 fs/namespace.c:2799 ksys_mount+0xdb/0x150 fs/namespace.c:3015 __do_sys_mount fs/namespace.c:3029 [inline] __se_sys_mount fs/namespace.c:3026 [inline] __x64_sys_mount+0xbe/0x150 fs/namespace.c:3026 do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459279 Code: 76 1b 48 8b 0e 48 8b 17 48 83 c6 08 48 83 c7 08 48 83 eb 08 48 39 d1 74 e3 c6 00 00 c3 48 8b 4c 1e f8 48 8b 54 1f f8 48 39 d1 <0f> 94 00 c3 48 83 fb 00 74 37 48 8d 0c dd 00 00 00 00 48 f7 d9 40 RSP: 002b:00007fe00e510c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 0000000000459279 RDX: 00000000200000c0 RSI: 0000000020000080 RDI: 0000000000000000 RBP: 000000000075bf20 R08: 0000000020000340 R09: 0000000000000000 R10: 0000000000008040 R11: 0000000000000246 R12: 00007fe00e5116d4 R13: 00000000004c53e2 R14: 00000000004d9550 R15: 00000000ffffffff Showing all locks held in the system: 1 lock held by khungtaskd/1031: #0: 00000000ebacd34a (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x27e kernel/locking/lockdep.c:4435 2 locks held by kworker/0:2/2734: #0: 000000000c5b4300 ((wq_completion)"events"){+.+.}, at: __write_once_size include/linux/compiler.h:220 [inline] #0: 000000000c5b4300 ((wq_completion)"events"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 000000000c5b4300 ((wq_completion)"events"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 000000000c5b4300 ((wq_completion)"events"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline] #0: 000000000c5b4300 ((wq_completion)"events"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 000000000c5b4300 ((wq_completion)"events"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 000000000c5b4300 ((wq_completion)"events"){+.+.}, at: process_one_work+0x87e/0x1750 kernel/workqueue.c:2124 #1: 000000001c160b0e ((work_completion)(&m->rq)){+.+.}, at: process_one_work+0x8b4/0x1750 kernel/workqueue.c:2128 1 lock held by rsyslogd/7428: #0: 00000000e0f64b57 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:767 2 locks held by getty/7551: #0: 00000000865c7ce5 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:363 #1: 000000008c9d4116 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154 2 locks held by getty/7552: #0: 00000000e949c3e0 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:363 #1: 000000001ddc85a1 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154 2 locks held by getty/7553: #0: 0000000012991a68 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:363 #1: 00000000200aa7ff (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154 2 locks held by getty/7554: #0: 00000000eb523d92 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:363 #1: 000000001a0441e4 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154 2 locks held by getty/7555: #0: 00000000edd28d53 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:363 #1: 00000000b95eb1b8 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154 2 locks held by getty/7556: #0: 00000000ad0a23f5 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:363 #1: 00000000c3b7c6d0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154 2 locks held by getty/7557: #0: 00000000dd9e23d3 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:363 #1: 0000000077395e22 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1031 Comm: khungtaskd Not tainted 4.19.48 #20 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x172/0x1f0 lib/dump_stack.c:113 nmi_cpu_backtrace.cold+0x63/0xa4 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1b0/0x1f8 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:203 [inline] watchdog+0x9df/0xee0 kernel/hung_task.c:287 kthread+0x354/0x420 kernel/kthread.c:246 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 23 Comm: kworker/u4:1 Not tainted 4.19.48 #20 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: bat_events batadv_nc_worker RIP: 0010:get_current arch/x86/include/asm/current.h:15 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x8/0x50 kernel/kcov.c:100 Code: 88 ea ff 48 c7 05 b4 74 cb 08 00 00 00 00 e9 ca e9 ff ff 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 48 89 e5 48 8b 75 08 <65> 48 8b 04 25 40 ee 01 00 65 8b 15 98 e9 96 7e 81 e2 00 01 1f 00 RSP: 0018:ffff8880aa3dfcd0 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffff8880933ddd40 RCX: ffffffff86d44865 RDX: 0000000000000000 RSI: ffffffff86d44be8 RDI: 0000000000000001 RBP: ffff8880aa3dfcd0 R08: ffff8880aa3ce600 R09: 0000000000000002 R10: ffff8880aa3ceed0 R11: 9e7f64a036f0bf43 R12: 0000000000000000 R13: 00000000000000de R14: ffff88808e6f8770 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f1d81bf4000 CR3: 00000000897e6000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rcu_read_lock include/linux/rcupdate.h:630 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:419 [inline] batadv_nc_worker+0x4c8/0x760 net/batman-adv/network-coding.c:730 process_one_work+0x989/0x1750 kernel/workqueue.c:2153 worker_thread+0x98/0xe40 kernel/workqueue.c:2296 kthread+0x354/0x420 kernel/kthread.c:246 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415