linux/sound
Arjan van de Ven c6482dde1c [PATCH] fix AB-BA deadlock inversion at cs46xx_dsp_remove_scb
There is a code sequence where the locking is substream->self_group.lock
-> ins->scbs[index].lock

substream->self_group.lock is interrupt safe, and taken from irq context
as well (trace is snipped for brevity)

so what can happen is

   cpu 0                   	cpu 1
   user context			user context

				take ins->scbs[index].lock without disabling interrupts

   get substream->self_group.lock (irqsafe)
   try to get ins->scbs[index].lock (spins)

				interrupt happens
				try to get substream->self_group.lock (spins)

which is an obvious AB-BA deadlock

fix is to just take the lock with _irqsafe

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Cc: Jaroslav Kysela <perex@suse.cz>
Acked-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-07-04 10:24:57 -07:00
..
aoa
arm
core [PATCH] lockdep: annotate sound/core/seq/seq_device.c 2006-07-03 15:27:08 -07:00
drivers
i2c
isa
mips
oss
parisc
pci [PATCH] fix AB-BA deadlock inversion at cs46xx_dsp_remove_scb 2006-07-04 10:24:57 -07:00
pcmcia
ppc
sparc
synth
usb
Kconfig
last.c
Makefile
sound_core.c
sound_firmware.c