kernel_optimize_test/include
Takashi Iwai 3194ed4979 ALSA: hda - Fix possible race on regmap bypass flip
HD-audio driver uses regmap cache bypass feature for reading a raw
value without the cache.  But this is racy since both the cached and
the uncached reads may occur concurrently.  The former is done via the
normal control API access while the latter comes from the proc file
read.

Even though the regmap itself has the protection against the
concurrent accesses, the flag set/reset is done without the
protection, so it may lead to inconsistent state of bypass flag that
doesn't match with the current read and occasionally result in a
kernel WARNING like:
  WARNING: CPU: 3 PID: 2731 at drivers/base/regmap/regcache.c:499 regcache_cache_only+0x78/0x93

One way to work around such a problem is to wrap with a mutex.  But in
this case, the solution is simpler: for the uncached read, we just
skip the regmap and directly calls its accessor.  The verb execution
there is protected by itself, so basically it's safe to call
individually.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=116171
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2016-04-21 17:59:17 +02:00
..
acpi
asm-generic arch, ftrace: for KASAN put hard/soft IRQ entries into separate sections 2016-03-25 16:37:42 -07:00
clocksource
crypto
drm
dt-bindings
keys
kvm
linux Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-04-03 07:06:53 -05:00
math-emu
media
memory
misc
net
pcmcia
ras
rdma
rxrpc
scsi SCSI misc on 20160326 2016-03-26 11:31:01 -07:00
soc
sound ALSA: hda - Fix possible race on regmap bypass flip 2016-04-21 17:59:17 +02:00
target target: add a new add_wwn_groups fabrics method 2016-03-30 20:06:44 -07:00
trace mm/page_isolation: fix tracepoint to mirror check function behavior 2016-04-01 17:03:37 -05:00
uapi Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-04-03 07:06:53 -05:00
video
xen
Kbuild