Takashi Iwai b5834d888a ALSA: emux: Fix mutex deadlock in OSS emulation ... commit 1c94e65c66 upstream. The OSS emulation in synth-emux helper has a potential AB/BA deadlock at the simultaneous closing and opening: close -> snd_seq_release() -> sne_seq_free_client() -> snd_seq_delete_all_ports(): takes client->ports_mutex -> port_delete() -> snd_emux_unuse(): takes emux->register_mutex open -> snd_seq_oss_open() -> snd_emux_open_seq_oss(): takes emux->register_mutex -> snd_seq_event_port_attach() -> snd_seq_create_port(): takes client->ports_mutex This patch addresses the deadlock by reducing the rance taking emux->register_mutex in snd_emux_open_seq_oss(). The lock is needed for the refcount handling, so move it locally. The calls in emux_seq.c are already with the mutex, thus they are replaced with the version without mutex lock/unlock. Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2015-05-13 05:16:56 -07:00
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emux	ALSA: emux: Fix mutex deadlock in OSS emulation	2015-05-13 05:16:56 -07:00
Makefile	ALSA: clean up the logic for building sequencer modules	2009-05-29 11:49:42 +02:00
util_mem.c	sound: Add module.h to the previously silent sound users	2011-10-31 19:31:21 -04:00