Steven Rostedt (Google) 259cb4dee1 ALSA: Use del_timer_sync() before freeing timer ... commit f0a868788f upstream. The current code for freeing the emux timer is extremely dangerous: CPU0 CPU1 ---- ---- snd_emux_timer_callback() snd_emux_free() spin_lock(&emu->voice_lock) del_timer(&emu->tlist); <-- returns immediately spin_unlock(&emu->voice_lock); [..] kfree(emu); spin_lock(&emu->voice_lock); [BOOM!] Instead just use del_timer_sync() which will wait for the timer to finish before continuing. No need to check if the timer is active or not when doing so. This doesn't fix the race of a possible re-arming of the timer, but at least it won't use the data that has just been freed. [ Fixed unused variable warning by tiwai ] Cc: stable@vger.kernel.org Fixes: 1da177e4c3 ("Linux-2.6.12-rc2") Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Link: https://lore.kernel.org/r/20221026231236.6834b551@gandalf.local.home Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2022-11-03 23:59:10 +09:00
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emux	ALSA: Use del_timer_sync() before freeing timer	2022-11-03 23:59:10 +09:00
Kconfig	treewide: Add SPDX license identifier - Makefile/Kconfig	2019-05-21 10:50:46 +02:00
Makefile	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
util_mem.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156	2019-05-30 11:26:35 -07:00