Hello,
The following program creates deadlocked processed in snd_seq_pool_done:
https://gist.githubusercontent.com/dvyukov/1c9b1e4641f46c16a42cdb4458bbe8fd/...
# cat /proc/2964/status Name: a.out State: D (disk sleep) Tgid: 2964 Ngid: 0 Pid: 2964 PPid: 2956 TracerPid: 0 Uid: 0 0 0 0 Gid: 0 0 0 0 FDSize: 0 Groups: 0 NStgid: 2964 NSpid: 2964 NSpgid: 2964 NSsid: 2956 Threads: 1 SigQ: 1/3304 SigPnd: 0000000000000000 ShdPnd: 0000000000000100 SigBlk: 0000000000000000 SigIgn: 0000000000000000 SigCgt: 0000000180000000 CapInh: 0000000000000000 CapPrm: 0000003fffffffff CapEff: 0000003fffffffff CapBnd: 0000003fffffffff CapAmb: 0000000000000000 NoNewPrivs: 0 Seccomp: 0 Cpus_allowed: f Cpus_allowed_list: 0-3 Mems_allowed: 00000000,00000001 Mems_allowed_list: 0 voluntary_ctxt_switches: 103997 nonvoluntary_ctxt_switches: 0
# cat /proc/2964/task/*/stack [<ffffffff8356c96b>] snd_seq_pool_done+0x31b/0x620 sound/core/seq/seq_memory.c:435 [<ffffffff83571961>] snd_seq_fifo_delete+0x161/0x1f0 sound/core/seq/seq_fifo.c:83 [<ffffffff83562b4f>] snd_seq_release+0x7f/0xe0 sound/core/seq/seq_clientmgr.c:368 [<ffffffff81a8aae2>] __fput+0x332/0x7f0 fs/file_table.c:208 [<ffffffff81a8b025>] ____fput+0x15/0x20 fs/file_table.c:244 [<ffffffff814c782a>] task_work_run+0x18a/0x260 kernel/task_work.c:116 [<ffffffff81451a86>] exit_task_work include/linux/task_work.h:21 [inline] [<ffffffff81451a86>] do_exit+0x1956/0x2900 kernel/exit.c:873 [<ffffffff81457579>] do_group_exit+0x149/0x420 kernel/exit.c:977 [<ffffffff8145786d>] SYSC_exit_group kernel/exit.c:988 [inline] [<ffffffff8145786d>] SyS_exit_group+0x1d/0x20 kernel/exit.c:986 [<ffffffff8457c781>] entry_SYSCALL_64_fastpath+0x1f/0xc2 [<ffffffffffffffff>] 0xffffffffffffffff