kernel_samsung_sm7125

jenna

History

Arjan van de Ven 763437a9e7 ALSA: pcm - fix race condition in wait_for_avail() wait_for_avail() in pcm_lib.c has a race in it (observed in practice by an Intel validation group). The function is supposed to return once space in the buffer has become available, or if some timeout happens. The entity that creates space (irq handler of sound driver and some such) will do a wake up on a waitqueue that this function registers for. However there are two races in the existing code 1) If space became available between the caller noticing there was no space and this function actually sleeping, the wakeup is missed and the timeout condition will happen instead 2) If a wakeup happened but not sufficient space became available, the code will loop again and wait for more space. However, if the second wake comes in prior to hitting the schedule_timeout_interruptible(), it will be missed, and potentially you'll wait out until the timeout happens. The fix consists of using more careful setting of the current state (so that if a wakeup happens in the main loop window, the schedule_timeout() falls through) and by checking for available space prior to going into the schedule_timeout() loop, but after being on the waitqueue and having the state set to interruptible. [tiwai: the following changes have been added to Arjan's original patch: - merged akpm's fix for waitqueue adding order into a single patch - reduction of duplicated code of avail check ] Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: <stable@kernel.org> Signed-off-by: Takashi Iwai <tiwai@suse.de>		14 years ago
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oss	ALSA: core: remove unused variables.	14 years ago
seq	ALSA: core: remove unused variables.	14 years ago
Kconfig	…
Makefile	…
control.c	ALSA: core: remove unused variables.	14 years ago
control_compat.c	…
device.c	ALSA: core: sparse cleanups	14 years ago
hrtimer.c	ALSA: hrtimer: remove superfluous tasklet invocation	14 years ago
hwdep.c	…
hwdep_compat.c	…
info.c	get rid of create_proc_entry() abuses - proc_mkdir() is there for purpose	14 years ago
info_oss.c	…
init.c	ALSA: core: remove unused variables.	14 years ago
isadma.c	…
jack.c	ALSA: fix one memory leak in sound jack	14 years ago
memalloc.c	ALSA: core: sparse cleanups	14 years ago
memory.c	…
misc.c	ALSA: Use %pV for snd_printk()	14 years ago
pcm.c	ALSA: core: sparse cleanups	14 years ago
pcm_compat.c	ALSA: sound/core/pcm_compat.c: adjust array index	14 years ago
pcm_lib.c	ALSA: pcm - fix race condition in wait_for_avail()	14 years ago
pcm_memory.c	Fix common misspellings	14 years ago
pcm_misc.c	ALSA: core: sparse cleanups	14 years ago
pcm_native.c	ALSA: core: remove unused variables.	14 years ago
pcm_timer.c	…
rawmidi.c	ALSA: Use krealloc() in possible places	14 years ago
rawmidi_compat.c	…
rtctimer.c	ALSA: rtctimer.c needs module.h	14 years ago
sgbuf.c	…
sound.c	…
sound_oss.c	…
timer.c	ALSA: timer - Add NULL-check for invalid slave timer	14 years ago
timer_compat.c	…
vmaster.c	Fix common misspellings	14 years ago