INFO: task syz-executor.1:8606 blocked for more than 143 seconds. Not tainted 5.3.0+ #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.1 D23448 8606 1 0x20024004 Call Trace: context_switch kernel/sched/core.c:3384 [inline] __schedule+0x76e/0x17d0 kernel/sched/core.c:4056 schedule+0xd9/0x260 kernel/sched/core.c:4123 exp_funnel_lock kernel/rcu/tree_exp.h:308 [inline] synchronize_rcu_expedited+0x57f/0x5f0 kernel/rcu/tree_exp.h:817 bdi_remove_from_list mm/backing-dev.c:1004 [inline] bdi_unregister+0x191/0x610 mm/backing-dev.c:1010 release_bdi mm/backing-dev.c:1032 [inline] kref_put include/linux/kref.h:65 [inline] bdi_put+0x164/0x1a0 mm/backing-dev.c:1041 generic_shutdown_super+0x2b0/0x370 fs/super.c:476 kill_anon_super+0x3e/0x60 fs/super.c:1106 fuse_kill_sb_anon+0x1e/0x30 fs/fuse/inode.c:1258 deactivate_locked_super+0x95/0x100 fs/super.c:335 deactivate_super fs/super.c:366 [inline] deactivate_super+0x1b2/0x1d0 fs/super.c:362 cleanup_mnt+0x351/0x4b0 fs/namespace.c:1102 __cleanup_mnt+0x16/0x20 fs/namespace.c:1109 task_work_run+0x145/0x1c0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x316/0x380 arch/x86/entry/common.c:163 prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline] syscall_return_slowpath arch/x86/entry/common.c:274 [inline] do_syscall_32_irqs_on arch/x86/entry/common.c:348 [inline] do_fast_syscall_32+0xb87/0xdb3 arch/x86/entry/common.c:404 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 RIP: 0023:0xf7f95a29 Code: Bad RIP value. RSP: 002b:000000000847ed1c EFLAGS: 00000212 ORIG_RAX: 0000000000000034 RAX: 0000000000000000 RBX: 000000000847edac RCX: 0000000000000002 RDX: 000000005721c198 RSI: 000000005721c1e0 RDI: 00000000080d48b8 RBP: 000000000847edac R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Showing all locks held in the system: 1 lock held by khungtaskd/1063: #0: ffffffff88fab280 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x27e kernel/locking/lockdep.c:5337 1 lock held by rsyslogd/8475: #0: ffff88808aeeade0 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:801 2 locks held by getty/8566: #0: ffff8880a1036dd0 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f3f2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 2 locks held by getty/8567: #0: ffff8880a0ca6510 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f352e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 2 locks held by getty/8568: #0: ffff888091641550 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f432e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 2 locks held by getty/8569: #0: ffff888094fc8cd0 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f252e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 2 locks held by getty/8570: #0: ffff888090c33610 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f192e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 2 locks held by getty/8571: #0: ffff8880a743f350 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f112e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 2 locks held by getty/6446: #0: ffff888091b657d0 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90015f3b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1063 Comm: khungtaskd Not tainted 5.3.0+ #0 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+0x70/0xb2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x23b/0x28b 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:205 [inline] watchdog+0x9d0/0xef0 kernel/hung_task.c:289 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 2550 Comm: kworker/u4:4 Not tainted 5.3.0+ #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: bat_events batadv_nc_worker RIP: 0010:__lock_acquire+0x555/0x4e70 kernel/locking/lockdep.c:3925 Code: ff 4c 89 9d 48 ff ff ff e8 b8 e7 ff ff 4c 8b 9d 48 ff ff ff 85 c0 4c 8b 95 40 ff ff ff 0f 84 c2 0c 00 00 48 c7 c2 e0 90 ae 8a <48> b8 00 00 00 00 00 fc ff df 48 c1 ea 03 0f b6 14 02 48 c7 c0 e0 RSP: 0018:ffff8880a230faa8 EFLAGS: 00000002 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000000000008 RDX: ffffffff8aae90e0 RSI: 0000000000000008 RDI: ffffffff8a7b8310 RBP: ffff8880a230fbb8 R08: 1ffffffff14ef741 R09: fffffbfff14ef742 R10: ffff8880a2300fe8 R11: ffff8880a2300700 R12: 000000000000057c R13: ffff8880a230100a R14: 0000000000000000 R15: 000000000004057c FS: 0000000000000000(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffff600400 CR3: 000000009b5bb000 CR4: 00000000001426f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4487 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline] _raw_spin_lock_bh+0x33/0x50 kernel/locking/spinlock.c:175 spin_lock_bh include/linux/spinlock.h:343 [inline] batadv_nc_purge_paths+0xd8/0x370 net/batman-adv/network-coding.c:441 batadv_nc_worker+0x29c/0x760 net/batman-adv/network-coding.c:719 process_one_work+0x9af/0x1740 kernel/workqueue.c:2269 worker_thread+0x98/0xe40 kernel/workqueue.c:2415 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352