INFO: task syz-executor.5:15594 blocked for more than 143 seconds. Not tainted 6.3.0-rc4-syzkaller-00224-g00c7b5f4ddc5 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.5 state:D stack:26600 pid:15594 ppid:5125 flags:0x20004004 Call Trace: context_switch kernel/sched/core.c:5307 [inline] __schedule+0xc91/0x5770 kernel/sched/core.c:6625 schedule+0xde/0x1a0 kernel/sched/core.c:6701 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6760 __mutex_lock_common kernel/locking/mutex.c:679 [inline] __mutex_lock+0xa3b/0x1350 kernel/locking/mutex.c:747 tty_open_by_driver drivers/tty/tty_io.c:2045 [inline] tty_open+0x59c/0x1010 drivers/tty/tty_io.c:2128 chrdev_open+0x26a/0x770 fs/char_dev.c:414 do_dentry_open+0x6cc/0x13f0 fs/open.c:920 do_open fs/namei.c:3560 [inline] path_openat+0x1baa/0x2750 fs/namei.c:3715 do_filp_open+0x1ba/0x410 fs/namei.c:3742 do_sys_openat2+0x16d/0x4c0 fs/open.c:1348 do_sys_open fs/open.c:1364 [inline] __do_compat_sys_openat fs/open.c:1424 [inline] __se_compat_sys_openat fs/open.c:1422 [inline] __ia32_compat_sys_openat+0x143/0x1f0 fs/open.c:1422 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline] __do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178 do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203 entry_SYSENTER_compat_after_hwframe+0x70/0x82 RIP: 0023:0xf7f7a579 RSP: 002b:00000000f7f75170 EFLAGS: 00000286 ORIG_RAX: 0000000000000127 RAX: ffffffffffffffda RBX: 00000000ffffff9c RCX: 00000000f7f751c0 RDX: 0000000000000002 RSI: 0000000000000000 RDI: 00000000f734d000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000296 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Showing all locks held in the system: 1 lock held by rcu_tasks_kthre/12: #0: ffffffff8c794a30 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x31/0xd80 kernel/rcu/tasks.h:510 1 lock held by rcu_tasks_trace/13: #0: ffffffff8c794730 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x31/0xd80 kernel/rcu/tasks.h:510 1 lock held by khungtaskd/28: #0: ffffffff8c795580 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x340 kernel/locking/lockdep.c:6495 2 locks held by kworker/u4:5/4092: 2 locks held by getty/4762: #0: ffff88814b510098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x26/0x80 drivers/tty/tty_ldisc.c:244 #1: ffffc900015802f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xef4/0x13e0 drivers/tty/n_tty.c:2177 3 locks held by syz-executor.1/15480: 1 lock held by syz-executor.5/15594: #0: ffffffff8d229f48 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2045 [inline] #0: ffffffff8d229f48 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x59c/0x1010 drivers/tty/tty_io.c:2128 1 lock held by syz-executor.4/15671: #0: ffffffff8d229f48 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2045 [inline] #0: ffffffff8d229f48 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x59c/0x1010 drivers/tty/tty_io.c:2128 1 lock held by syz-executor.3/15673: #0: ffffffff8d229f48 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2045 [inline] #0: ffffffff8d229f48 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x59c/0x1010 drivers/tty/tty_io.c:2128 1 lock held by syz-executor.5/15713: #0: ffffffff8d229f48 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2045 [inline] #0: ffffffff8d229f48 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x59c/0x1010 drivers/tty/tty_io.c:2128 1 lock held by syz-executor.5/15793: #0: ffffffff8d229f48 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2045 [inline] #0: ffffffff8d229f48 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x59c/0x1010 drivers/tty/tty_io.c:2128 1 lock held by syz-executor.4/15801: #0: ffffffff8d229f48 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2045 [inline] #0: ffffffff8d229f48 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x59c/0x1010 drivers/tty/tty_io.c:2128 1 lock held by syz-executor.3/15802: #0: ffffffff8d229f48 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2045 [inline] #0: ffffffff8d229f48 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x59c/0x1010 drivers/tty/tty_io.c:2128 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 28 Comm: khungtaskd Not tainted 6.3.0-rc4-syzkaller-00224-g00c7b5f4ddc5 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106 nmi_cpu_backtrace+0x29c/0x350 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x2a4/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline] watchdog+0xe16/0x1090 kernel/hung_task.c:379 kthread+0x2e8/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 4092 Comm: kworker/u4:5 Not tainted 6.3.0-rc4-syzkaller-00224-g00c7b5f4ddc5 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023 Workqueue: bat_events batadv_nc_worker RIP: 0010:rcu_preempt_read_enter kernel/rcu/tree_plugin.h:377 [inline] RIP: 0010:__rcu_read_lock+0x2b/0xf0 kernel/rcu/tree_plugin.h:400 Code: 0f 1e fa 48 b8 00 00 00 00 00 fc ff df 55 53 65 48 8b 1c 25 80 b8 03 00 48 8d bb 3c 04 00 00 48 89 fa 48 c1 ea 03 0f b6 14 02 <48> 89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 9e 00 00 00 65 RSP: 0018:ffffc9000460fc70 EFLAGS: 00000a07 RAX: dffffc0000000000 RBX: ffff88802b1d8000 RCX: ffff88802703a780 RDX: 0000000000000000 RSI: ffffffff89ce3099 RDI: ffff88802b1d843c RBP: 0000000000000001 R08: 0000000000000004 R09: 0000000000000283 R10: 0000000000000400 R11: 0000000000000000 R12: ffffc9000460fda8 R13: 0000000000000000 R14: dffffc0000000000 R15: 0000000000000283 FS: 0000000000000000(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000c00dab5230 CR3: 000000002acac000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rcu_read_lock include/linux/rcupdate.h:771 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:408 [inline] batadv_nc_worker+0x10c/0xfe0 net/batman-adv/network-coding.c:719 process_one_work+0x991/0x15c0 kernel/workqueue.c:2390 worker_thread+0x669/0x1090 kernel/workqueue.c:2537 kthread+0x2e8/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308