INFO: task syz-executor.0:23836 blocked for more than 143 seconds. Not tainted 5.2.0+ #37 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D22456 23836 8183 0x00004004 Call Trace: context_switch kernel/sched/core.c:3254 [inline] __schedule+0x8b7/0xcd0 kernel/sched/core.c:3880 schedule+0x12f/0x1d0 kernel/sched/core.c:3944 rwsem_down_read_slowpath+0x6a5/0xb60 kernel/locking/rwsem.c:1079 __down_read+0xa8/0x3d0 kernel/locking/rwsem.c:1304 down_read_nested+0x4e/0x60 kernel/locking/rwsem.c:1557 deliver_to_subscribers sound/core/seq/seq_clientmgr.c:683 [inline] snd_seq_deliver_event+0x26a/0x870 sound/core/seq/seq_clientmgr.c:828 snd_seq_kernel_client_dispatch+0x1f0/0x2f0 sound/core/seq/seq_clientmgr.c:2324 dummy_input+0x1bc/0x2c0 sound/core/seq/seq_dummy.c:90 snd_seq_deliver_single_event+0x554/0xcc0 sound/core/seq/seq_clientmgr.c:638 deliver_to_subscribers sound/core/seq/seq_clientmgr.c:693 [inline] snd_seq_deliver_event+0x4fa/0x870 sound/core/seq/seq_clientmgr.c:828 snd_seq_kernel_client_dispatch+0x1f0/0x2f0 sound/core/seq/seq_clientmgr.c:2324 dummy_input+0x1bc/0x2c0 sound/core/seq/seq_dummy.c:90 snd_seq_deliver_single_event+0x554/0xcc0 sound/core/seq/seq_clientmgr.c:638 snd_seq_deliver_event+0x24d/0x870 sound/core/seq/seq_clientmgr.c:839 snd_seq_kernel_client_dispatch+0x1f0/0x2f0 sound/core/seq/seq_clientmgr.c:2324 snd_seq_oss_dispatch sound/core/seq/oss/seq_oss_device.h:138 [inline] snd_seq_oss_midi_reset+0x43c/0x850 sound/core/seq/oss/seq_oss_midi.c:470 snd_seq_oss_synth_reset+0x3aa/0x9d0 sound/core/seq/oss/seq_oss_synth.c:404 snd_seq_oss_reset+0x72/0x280 sound/core/seq/oss/seq_oss_init.c:435 snd_seq_oss_release+0xcb/0x2c0 sound/core/seq/oss/seq_oss_init.c:412 odev_release+0x56/0x70 sound/core/seq/oss/seq_oss.c:140 __fput+0x2e4/0x740 fs/file_table.c:280 ____fput+0x15/0x20 fs/file_table.c:313 task_work_run+0x17e/0x1c0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop arch/x86/entry/common.c:163 [inline] prepare_exit_to_usermode+0x459/0x580 arch/x86/entry/common.c:194 syscall_return_slowpath+0x113/0x4a0 arch/x86/entry/common.c:274 do_syscall_64+0x126/0x140 arch/x86/entry/common.c:299 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459829 Code: 24 60 48 8b 42 08 48 8b 4a 10 48 8b 5a 18 48 8b 72 20 48 8b 7a 28 48 8b 3f 4c 8b 42 30 48 8b 52 38 48 85 d2 76 62 48 89 44 24 <58> 4c 89 44 24 28 48 89 0c 24 48 89 5c 24 08 48 c7 44 24 10 00 00 RSP: 002b:00007f069acbac78 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffea RBX: 0000000000000004 RCX: 0000000000459829 RDX: 0000000000004002 RSI: 0000000020000080 RDI: ffffffffffffff9c RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f069acbb6d4 R13: 00000000004c62bb R14: 00000000004daf48 R15: 00000000ffffffff INFO: task syz-executor.2:23843 blocked for more than 143 seconds. Not tainted 5.2.0+ #37 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D25960 23843 8190 0x00004004 Call Trace: context_switch kernel/sched/core.c:3254 [inline] __schedule+0x8b7/0xcd0 kernel/sched/core.c:3880 schedule+0x12f/0x1d0 kernel/sched/core.c:3944 rwsem_down_write_slowpath+0x8cf/0xe80 kernel/locking/rwsem.c:1198 __down_write kernel/locking/rwsem.c:1349 [inline] down_write+0x176/0x180 kernel/locking/rwsem.c:1485 delete_and_unsubscribe_port+0x67/0x440 sound/core/seq/seq_ports.c:528 snd_seq_port_connect+0x328/0x460 sound/core/seq/seq_ports.c:578 snd_seq_ioctl_subscribe_port+0x394/0x750 sound/core/seq/seq_clientmgr.c:1484 snd_seq_ioctl+0x209/0x390 sound/core/seq/seq_clientmgr.c:2158 do_vfs_ioctl+0x7d4/0x18f0 fs/ioctl.c:46 ksys_ioctl fs/ioctl.c:713 [inline] __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl fs/ioctl.c:718 [inline] __x64_sys_ioctl+0xe3/0x120 fs/ioctl.c:718 do_syscall_64+0xfe/0x140 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459829 Code: 24 60 48 8b 42 08 48 8b 4a 10 48 8b 5a 18 48 8b 72 20 48 8b 7a 28 48 8b 3f 4c 8b 42 30 48 8b 52 38 48 85 d2 76 62 48 89 44 24 <58> 4c 89 44 24 28 48 89 0c 24 48 89 5c 24 08 48 c7 44 24 10 00 00 RSP: 002b:00007fd4cb495c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459829 RDX: 0000000020000140 RSI: 0000000040505330 RDI: 0000000000000003 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fd4cb4966d4 R13: 00000000004cd8a0 R14: 00000000004d77b0 R15: 00000000ffffffff Showing all locks held in the system: 1 lock held by khungtaskd/1057: #0: 000000005b3a4e19 (rcu_read_lock){....}, at: rcu_lock_acquire+0x4/0x30 include/linux/rcupdate.h:207 1 lock held by rsyslogd/8057: #0: 00000000648fd468 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x243/0x2e0 fs/file.c:801 2 locks held by getty/8147: #0: 000000003f6d1d2a (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:272 #1: 00000000eed6ed10 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x2ee/0x1c80 drivers/tty/n_tty.c:2156 2 locks held by getty/8148: #0: 00000000e0dede2f (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:272 #1: 000000004e86ecd0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x2ee/0x1c80 drivers/tty/n_tty.c:2156 2 locks held by getty/8149: #0: 000000000eff8607 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:272 #1: 0000000096004885 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x2ee/0x1c80 drivers/tty/n_tty.c:2156 2 locks held by getty/8150: #0: 00000000fbbc2494 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:272 #1: 0000000007eea81a (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x2ee/0x1c80 drivers/tty/n_tty.c:2156 2 locks held by getty/8151: #0: 000000002f58b725 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:272 #1: 00000000d566e37f (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x2ee/0x1c80 drivers/tty/n_tty.c:2156 2 locks held by getty/8152: #0: 0000000050ae5df5 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:272 #1: 000000007c74bf19 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x2ee/0x1c80 drivers/tty/n_tty.c:2156 2 locks held by getty/8153: #0: 00000000f4988887 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:272 #1: 000000002a7758ed (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x2ee/0x1c80 drivers/tty/n_tty.c:2156 3 locks held by syz-executor.0/23836: #0: 0000000030df1866 (register_mutex#4){+.+.}, at: odev_release+0x4e/0x70 sound/core/seq/oss/seq_oss.c:139 #1: 00000000865f2ff1 (&grp->list_mutex#2/2){.+.+}, at: deliver_to_subscribers sound/core/seq/seq_clientmgr.c:683 [inline] #1: 00000000865f2ff1 (&grp->list_mutex#2/2){.+.+}, at: snd_seq_deliver_event+0x26a/0x870 sound/core/seq/seq_clientmgr.c:828 #2: 00000000865f2ff1 (&grp->list_mutex#2/3){.+.+}, at: deliver_to_subscribers sound/core/seq/seq_clientmgr.c:683 [inline] #2: 00000000865f2ff1 (&grp->list_mutex#2/3){.+.+}, at: snd_seq_deliver_event+0x26a/0x870 sound/core/seq/seq_clientmgr.c:828 2 locks held by syz-executor.2/23843: #0: 000000009a474f78 (&client->ioctl_mutex){+.+.}, at: snd_seq_ioctl+0x1e4/0x390 sound/core/seq/seq_clientmgr.c:2157 #1: 00000000865f2ff1 (&grp->list_mutex#2){++++}, at: delete_and_unsubscribe_port+0x67/0x440 sound/core/seq/seq_ports.c:528 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1057 Comm: khungtaskd Not tainted 5.2.0+ #37 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+0x1d8/0x2f8 lib/dump_stack.c:113 nmi_cpu_backtrace+0xb0/0x1a0 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x14c/0x240 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x10/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_all_cpu_backtrace+0x17/0x20 include/linux/nmi.h:146 check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline] watchdog+0xbcc/0xbe0 kernel/hung_task.c:289 kthread+0x332/0x350 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: 668 Comm: kworker/u4:3 Not tainted 5.2.0+ #37 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: bat_events batadv_nc_worker RIP: 0010:__preempt_count_add arch/x86/include/asm/preempt.h:79 [inline] RIP: 0010:rcu_read_lock_sched_notrace include/linux/rcupdate.h:708 [inline] RIP: 0010:trace_lock_acquire+0x140/0x1b0 include/trace/events/lock.h:13 Code: 83 85 00 00 00 89 c3 48 89 d8 48 c1 e8 06 48 8d 3c c5 e0 cb fd 88 be 08 00 00 00 e8 ca 4b 55 00 48 0f a3 1d f2 29 a2 07 73 51 <65> 83 05 54 5b a6 7e 01 48 8b 05 d9 1d 9f 07 e8 2c a4 07 00 85 c0 RSP: 0018:ffff8880a851fb38 EFLAGS: 00000057 RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff815ba1e6 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff88fdcbe0 RBP: ffff8880a851fb78 R08: dffffc0000000000 R09: fffffbfff11fb97d R10: fffffbfff11fb97d R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000002 R15: ffffffff88cd6380 FS: 0000000000000000(0000) GS:ffff8880aea00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ff2de79d000 CR3: 0000000099cb9000 CR4: 00000000001406f0 DR0: 0000000000000009 DR1: 0000000000000002 DR2: 0000000100000001 DR3: 000000000000003f DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x125/0x250 kernel/locking/lockdep.c:4412 rcu_lock_acquire+0x2e/0x40 include/linux/rcupdate.h:208 rcu_read_lock include/linux/rcupdate.h:592 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:407 [inline] batadv_nc_worker+0xdf/0x610 net/batman-adv/network-coding.c:718 process_one_work+0x83b/0x1150 kernel/workqueue.c:2269 worker_thread+0xc01/0x1630 kernel/workqueue.c:2415 kthread+0x332/0x350 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352