INFO: task syz-executor3:3522 blocked for more than 120 seconds. Not tainted 4.15.0-rc7+ #256 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor3 D24272 3522 3509 0x00000004 Call Trace: context_switch kernel/sched/core.c:2799 [inline] __schedule+0x8eb/0x2060 kernel/sched/core.c:3375 schedule+0xf5/0x430 kernel/sched/core.c:3434 schedule_preempt_disabled+0x10/0x20 kernel/sched/core.c:3492 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0xaad/0x1a80 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 snd_pcm_oss_write1 sound/core/oss/pcm_oss.c:1338 [inline] snd_pcm_oss_write+0x22d/0x830 sound/core/oss/pcm_oss.c:2646 do_loop_readv_writev fs/read_write.c:676 [inline] do_iter_write+0x3ca/0x540 fs/read_write.c:934 vfs_writev+0x18a/0x340 fs/read_write.c:977 do_writev+0xfc/0x2a0 fs/read_write.c:1012 SYSC_writev fs/read_write.c:1085 [inline] SyS_writev+0x27/0x30 fs/read_write.c:1082 entry_SYSCALL_64_fastpath+0x23/0x9a RIP: 0033:0x452ac9 RSP: 002b:00007f71e06cbc58 EFLAGS: 00000212 ORIG_RAX: 0000000000000014 RAX: ffffffffffffffda RBX: 000000000071bf58 RCX: 0000000000452ac9 RDX: 0000000000000005 RSI: 0000000020d30fb0 RDI: 0000000000000000 RBP: 00000000000003aa R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006f3890 R13: 00000000ffffffff R14: 00007f71e06cc6d4 R15: 0000000000000000 Showing all locks held in the system: 3 locks held by kworker/u4:1/21: #0: ((wq_completion)"%s""netns"){+.+.}, at: [<000000009d8b7ab1>] process_one_work+0xaaf/0x1b10 kernel/workqueue.c:2083 #1: (net_cleanup_work){+.+.}, at: [<0000000057b0e500>] process_one_work+0xb01/0x1b10 kernel/workqueue.c:2087 #2: (net_mutex){+.+.}, at: [<00000000272d2639>] cleanup_net+0x247/0xb50 net/core/net_namespace.c:450 2 locks held by khungtaskd/738: #0: (rcu_read_lock){....}, at: [<00000000d3caa368>] check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline] #0: (rcu_read_lock){....}, at: [<00000000d3caa368>] watchdog+0x1c5/0xd60 kernel/hung_task.c:249 #1: (tasklist_lock){.+.+}, at: [<00000000ad265c79>] debug_show_all_locks+0xd3/0x400 kernel/locking/lockdep.c:4464 2 locks held by getty/3465: #0: (&tty->ldisc_sem){++++}, at: [<000000000cbb9a4f>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000751be7e4>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/3466: #0: (&tty->ldisc_sem){++++}, at: [<000000000cbb9a4f>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000751be7e4>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/3467: #0: (&tty->ldisc_sem){++++}, at: [<000000000cbb9a4f>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000751be7e4>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/3468: #0: (&tty->ldisc_sem){++++}, at: [<000000000cbb9a4f>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000751be7e4>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/3469: #0: (&tty->ldisc_sem){++++}, at: [<000000000cbb9a4f>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000751be7e4>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/3470: #0: (&tty->ldisc_sem){++++}, at: [<000000000cbb9a4f>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000751be7e4>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/3471: #0: (&tty->ldisc_sem){++++}, at: [<000000000cbb9a4f>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000751be7e4>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 1 lock held by syz-executor3/3522: #0: (&runtime->oss.params_lock){+.+.}, at: [<00000000b64538d3>] snd_pcm_oss_write1 sound/core/oss/pcm_oss.c:1338 [inline] #0: (&runtime->oss.params_lock){+.+.}, at: [<00000000b64538d3>] snd_pcm_oss_write+0x22d/0x830 sound/core/oss/pcm_oss.c:2646 1 lock held by syz-executor1/3534: #0: (net_mutex){+.+.}, at: [<00000000a3f02c40>] copy_net_ns+0x239/0x580 net/core/net_namespace.c:410 1 lock held by syz-executor2/3536: #0: (net_mutex){+.+.}, at: [<00000000a3f02c40>] copy_net_ns+0x239/0x580 net/core/net_namespace.c:410 1 lock held by syz-executor7/3538: #0: (net_mutex){+.+.}, at: [<00000000a3f02c40>] copy_net_ns+0x239/0x580 net/core/net_namespace.c:410 1 lock held by syz-executor0/3540: #0: (net_mutex){+.+.}, at: [<00000000a3f02c40>] copy_net_ns+0x239/0x580 net/core/net_namespace.c:410 1 lock held by syz-executor5/3542: #0: (net_mutex){+.+.}, at: [<00000000a3f02c40>] copy_net_ns+0x239/0x580 net/core/net_namespace.c:410 1 lock held by syz-executor6/3543: #0: (net_mutex){+.+.}, at: [<00000000a3f02c40>] copy_net_ns+0x239/0x580 net/core/net_namespace.c:410 1 lock held by syz-executor4/3545: #0: (net_mutex){+.+.}, at: [<00000000a3f02c40>] copy_net_ns+0x239/0x580 net/core/net_namespace.c:410 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 738 Comm: khungtaskd Not tainted 4.15.0-rc7+ #256 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x257 lib/dump_stack.c:53 nmi_cpu_backtrace+0x1d2/0x210 lib/nmi_backtrace.c:103 nmi_trigger_cpumask_backtrace+0x122/0x180 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:138 [inline] check_hung_task kernel/hung_task.c:132 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:190 [inline] watchdog+0x90c/0xd60 kernel/hung_task.c:249 kthread+0x33c/0x400 kernel/kthread.c:238 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:524 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 3521 Comm: syz-executor3 Not tainted 4.15.0-rc7+ #256 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:memcpy_erms+0x8/0x10 arch/x86/lib/memcpy_64.S:54 RSP: 0018:ffff8801bfa1f7b0 EFLAGS: 00000246 RAX: ffffc900017899ec RBX: 0000000000000002 RCX: 0000000000000000 RDX: 0000000000000002 RSI: ffff8801bfa1f8a2 RDI: ffffc900017899ee RBP: ffff8801bfa1f7d0 R08: fffff520002f133e R09: fffff520002f133e R10: 0000000000000001 R11: fffff520002f133d R12: ffffc900017899ec R13: ffff8801bfa1f8a0 R14: dffffc0000000000 R15: ffffc900017899ec FS: 00007f71e06ed700(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020e1e000 CR3: 00000001c1252005 CR4: 00000000001606f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: memcpy include/linux/string.h:344 [inline] cvt_s16_to_native sound/core/oss/mulaw.c:164 [inline] mulaw_decode+0x52f/0x770 sound/core/oss/mulaw.c:195 mulaw_transfer+0x222/0x270 sound/core/oss/mulaw.c:273 snd_pcm_plug_write_transfer+0x22d/0x420 sound/core/oss/pcm_plugin.c:611 snd_pcm_oss_write2+0x260/0x420 sound/core/oss/pcm_oss.c:1311 snd_pcm_oss_write1 sound/core/oss/pcm_oss.c:1372 [inline] snd_pcm_oss_write+0x5fe/0x830 sound/core/oss/pcm_oss.c:2646 do_loop_readv_writev fs/read_write.c:676 [inline] do_iter_write+0x3ca/0x540 fs/read_write.c:934 vfs_writev+0x18a/0x340 fs/read_write.c:977 do_writev+0xfc/0x2a0 fs/read_write.c:1012 SYSC_writev fs/read_write.c:1085 [inline] SyS_writev+0x27/0x30 fs/read_write.c:1082 entry_SYSCALL_64_fastpath+0x23/0x9a RIP: 0033:0x452ac9 RSP: 002b:00007f71e06ecc58 EFLAGS: 00000212 ORIG_RAX: 0000000000000014 RAX: ffffffffffffffda RBX: 000000000071bea0 RCX: 0000000000452ac9 RDX: 0000000000000005 RSI: 0000000020d30fb0 RDI: 0000000000000000 RBP: 00000000000003cf R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006f3c08 R13: 00000000ffffffff R14: 00007f71e06ed6d4 R15: 0000000000000000 Code: 90 90 90 eb 1e 0f 1f 00 48 89 f8 48 89 d1 48 c1 e9 03 83 e2 07 f3 48 a5 89 d1 f3 a4 c3 66 0f 1f 44 00 00 48 89 f8 48 89 d1 f3 a4 0f 1f 80 00 00 00 00 48 89 f8 48 83 fa 20 72 7e 40 38 fe 7c