Comment 3 for bug 1750947

[ 800.271277] Freezing user space processes ...
[ 820.267656] Freezing of tasks failed after 20.006 seconds (1 tasks refusing to freeze, wq_busy=0):
[ 820.267704] alsa-sink-HDMI D 0 1554 1117 0x00000004
[ 820.267710] Call Trace:
[ 820.267723] __schedule+0x3c2/0x8b0
[ 820.267727] schedule+0x36/0x80
[ 820.267730] schedule_timeout+0x17a/0x360
[ 820.267735] ? call_timer_fn+0x140/0x140
[ 820.267745] snd_power_wait+0xba/0x110 [snd]
[ 820.267751] ? snd_power_wait+0xba/0x110 [snd]
[ 820.267756] ? wake_up_q+0x70/0x70
[ 820.267766] snd_pcm_common_ioctl1+0x41/0x930 [snd_pcm]
[ 820.267772] snd_pcm_playback_ioctl1+0x13e/0x250 [snd_pcm]
[ 820.267777] ? eventfd_ctx_read+0x67/0x210
[ 820.267784] snd_pcm_playback_ioctl+0x28/0x40 [snd_pcm]
[ 820.267789] do_vfs_ioctl+0xa1/0x5f0
[ 820.267792] SyS_ioctl+0x79/0x90
[ 820.267796] entry_SYSCALL_64_fastpath+0x1e/0xa9
[ 820.267798] RIP: 0033:0x7fb4d9bbdf07
[ 820.267800] RSP: 002b:00007fb4d5d3cc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
[ 820.267803] RAX: ffffffffffffffda RBX: 00007fb4d5d3cca0 RCX: 00007fb4d9bbdf07
[ 820.267805] RDX: 0000000001888d20 RSI: 0000000000004122 RDI: 0000000000000016
[ 820.267807] RBP: 0000000001888d20 R08: 0000000000000043 R09: 0000000000000001
[ 820.267808] R10: 000000000185f870 R11: 0000000000000246 R12: 0000000001888d20
[ 820.267810] R13: 0000000000000000 R14: 00007fb4d5d3a650 R15: 0000000000615080
[ 820.267837] OOM killer enabled.
[ 820.267838] Restarting tasks ... done.