INFO: task syz-executor.1:20439 blocked for more than 143 seconds. Not tainted 6.3.0-rc7-syzkaller-00043-gaf67688dca57 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.1 state:D stack:28104 pid:20439 ppid:5114 flags:0x00000004 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 snd_rawmidi_open+0x26c/0xb70 sound/core/rawmidi.c:474 snd_open+0x223/0x460 sound/core/sound.c:169 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_sys_openat fs/open.c:1380 [inline] __se_sys_openat fs/open.c:1375 [inline] __x64_sys_openat+0x143/0x1f0 fs/open.c:1375 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f68d383e2f4 RSP: 002b:00007f68d45d6ca0 EFLAGS: 00000293 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 6666666666666667 RCX: 00007f68d383e2f4 RDX: 0000000000008001 RSI: 00007f68d45d6d40 RDI: 00000000ffffff9c RBP: 00007f68d45d6d40 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000008001 R13: 00007f68d3acfb1f R14: 00007f68d45d7300 R15: 0000000000022000 Showing all locks held in the system: 1 lock held by rcu_tasks_kthre/12: #0: ffffffff8c794a70 (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: ffffffff8c794770 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x31/0xd80 kernel/rcu/tasks.h:510 1 lock held by ksoftirqd/1/21: 1 lock held by khungtaskd/28: #0: ffffffff8c7955c0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x340 kernel/locking/lockdep.c:6495 2 locks held by kworker/u4:6/2864: 2 locks held by getty/4750: #0: ffff888027c9b098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x26/0x80 drivers/tty/tty_ldisc.c:244 #1: ffffc900015902f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xef4/0x13e0 drivers/tty/n_tty.c:2177 1 lock held by syz-executor.1/25853: #0: ffff888149e75168 (&rmidi->open_mutex){+.+.}-{3:3}, at: rawmidi_release_priv+0x45/0x270 sound/core/rawmidi.c:581 1 lock held by syz-executor.5/2349: #0: ffff888149e75168 (&rmidi->open_mutex){+.+.}-{3:3}, at: rawmidi_release_priv+0x45/0x270 sound/core/rawmidi.c:581 1 lock held by syz-executor.4/20419: 1 lock held by syz-executor.1/20439: #0: ffff888149e75168 (&rmidi->open_mutex){+.+.}-{3:3}, at: snd_rawmidi_open+0x26c/0xb70 sound/core/rawmidi.c:474 1 lock held by syz-executor.5/20454: #0: ffff888149e75168 (&rmidi->open_mutex){+.+.}-{3:3}, at: snd_rawmidi_open+0x26c/0xb70 sound/core/rawmidi.c:474 1 lock held by syz-executor.4/20497: #0: ffff888149e75168 (&rmidi->open_mutex){+.+.}-{3:3}, at: snd_rawmidi_open+0x26c/0xb70 sound/core/rawmidi.c:474 1 lock held by syz-executor.1/20500: #0: ffff888149e75168 (&rmidi->open_mutex){+.+.}-{3:3}, at: snd_rawmidi_open+0x26c/0xb70 sound/core/rawmidi.c:474 1 lock held by syz-executor.3/20519: #0: ffff888149e75168 (&rmidi->open_mutex){+.+.}-{3:3}, at: snd_rawmidi_open+0x26c/0xb70 sound/core/rawmidi.c:474 1 lock held by syz-executor.5/20667: #0: ffff888149e75168 (&rmidi->open_mutex){+.+.}-{3:3}, at: snd_rawmidi_open+0x26c/0xb70 sound/core/rawmidi.c:474 1 lock held by syz-executor.4/20672: #0: ffff888149e75168 (&rmidi->open_mutex){+.+.}-{3:3}, at: snd_rawmidi_open+0x26c/0xb70 sound/core/rawmidi.c:474 1 lock held by syz-executor.1/20678: #0: ffff888149e75168 (&rmidi->open_mutex){+.+.}-{3:3}, at: snd_rawmidi_open+0x26c/0xb70 sound/core/rawmidi.c:474 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 28 Comm: khungtaskd Not tainted 6.3.0-rc7-syzkaller-00043-gaf67688dca57 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/30/2023 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: 21 Comm: ksoftirqd/1 Not tainted 6.3.0-rc7-syzkaller-00043-gaf67688dca57 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/30/2023 RIP: 0010:__stack_depot_save+0x111/0x510 lib/stackdepot.c:377 Code: c0 41 89 c0 29 c3 01 f8 41 c1 c0 04 44 31 c3 83 fe 03 77 92 83 fe 02 74 77 83 fe 03 74 6f 83 fe 01 74 70 48 8b 05 b7 2c c7 0d <89> d9 23 0d a7 2c c7 0d 48 8d 0c c8 48 8b 29 48 85 ed 75 12 e9 92 RSP: 0018:ffffc900001b76e0 EFLAGS: 00000286 RAX: ffff88823b400000 RBX: 000000008ed15b41 RCX: 00000000a0e2e0b3 RDX: 0000000000000010 RSI: 0000000000000002 RDI: 00000000fa329327 RBP: ffff88803fb1fdc0 R08: 000000006cfe6ae5 R09: ffffc900001b765c R10: 0000000000000000 R11: 0000000000094001 R12: 0000000000000001 R13: 0000000000000800 R14: ffffc900001b7750 R15: 0000000000000010 FS: 0000000000000000(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000555556c7c848 CR3: 000000000c571000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 000000000000003b DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: kasan_save_stack+0x32/0x40 mm/kasan/common.c:46 kasan_set_track+0x25/0x30 mm/kasan/common.c:52 kasan_save_free_info+0x2e/0x40 mm/kasan/generic.c:521 ____kasan_slab_free mm/kasan/common.c:236 [inline] ____kasan_slab_free+0x160/0x1c0 mm/kasan/common.c:200 kasan_slab_free include/linux/kasan.h:162 [inline] slab_free_hook mm/slub.c:1781 [inline] slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1807 slab_free mm/slub.c:3787 [inline] kmem_cache_free+0xe9/0x480 mm/slub.c:3809 kfree_skbmem+0xef/0x1b0 net/core/skbuff.c:922 __kfree_skb net/core/skbuff.c:979 [inline] kfree_skb_reason+0x186/0x3a0 net/core/skbuff.c:1011 kfree_skb include/linux/skbuff.h:1225 [inline] ip6_mc_input+0xa3c/0xf50 net/ipv6/ip6_input.c:590 dst_input include/net/dst.h:454 [inline] ip6_rcv_finish net/ipv6/ip6_input.c:79 [inline] NF_HOOK include/linux/netfilter.h:302 [inline] NF_HOOK include/linux/netfilter.h:296 [inline] ipv6_rcv+0x250/0x380 net/ipv6/ip6_input.c:309 __netif_receive_skb_one_core+0x114/0x180 net/core/dev.c:5480 __netif_receive_skb+0x1f/0x1c0 net/core/dev.c:5594 process_backlog+0x239/0x800 net/core/dev.c:5922 __napi_poll+0xb7/0x6f0 net/core/dev.c:6483 napi_poll net/core/dev.c:6550 [inline] net_rx_action+0x9c2/0xd80 net/core/dev.c:6660 __do_softirq+0x1d4/0x905 kernel/softirq.c:571 run_ksoftirqd kernel/softirq.c:934 [inline] run_ksoftirqd+0x31/0x60 kernel/softirq.c:926 smpboot_thread_fn+0x659/0x9e0 kernel/smpboot.c:164 kthread+0x2e8/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308