When ak4114 work calls its callback and the callback invokes ak4114_reinit(), it stalls due to flush_delayed_work(). For avoiding this, control the reentrance by introducing a refcount. Also flush_delayed_work() is replaced with cancel_delayed_work_sync().
The exactly same bug is present in ak4113.c and fixed as well.
Reported-by: Pavel Hofman pavel.hofman@ivitera.com Cc: stable@vger.kernel.org Signed-off-by: Takashi Iwai tiwai@suse.de --- include/sound/ak4113.h | 2 +- include/sound/ak4114.h | 2 +- sound/i2c/other/ak4113.c | 17 ++++++++--------- sound/i2c/other/ak4114.c | 18 ++++++++---------- 4 files changed, 18 insertions(+), 21 deletions(-)
diff --git a/include/sound/ak4113.h b/include/sound/ak4113.h index 2609048c1d44..3a34f6edc2d1 100644 --- a/include/sound/ak4113.h +++ b/include/sound/ak4113.h @@ -286,7 +286,7 @@ struct ak4113 { ak4113_write_t *write; ak4113_read_t *read; void *private_data; - unsigned int init:1; + atomic_t wq_processing; spinlock_t lock; unsigned char regmap[AK4113_WRITABLE_REGS]; struct snd_kcontrol *kctls[AK4113_CONTROLS]; diff --git a/include/sound/ak4114.h b/include/sound/ak4114.h index 52f02a60dba7..069299a88915 100644 --- a/include/sound/ak4114.h +++ b/include/sound/ak4114.h @@ -168,7 +168,7 @@ struct ak4114 { ak4114_write_t * write; ak4114_read_t * read; void * private_data; - unsigned int init: 1; + atomic_t wq_processing; spinlock_t lock; unsigned char regmap[6]; unsigned char txcsb[5]; diff --git a/sound/i2c/other/ak4113.c b/sound/i2c/other/ak4113.c index 1a3a6fa27158..c6bba99a90b2 100644 --- a/sound/i2c/other/ak4113.c +++ b/sound/i2c/other/ak4113.c @@ -56,8 +56,7 @@ static inline unsigned char reg_read(struct ak4113 *ak4113, unsigned char reg)
static void snd_ak4113_free(struct ak4113 *chip) { - chip->init = 1; /* don't schedule new work */ - mb(); + atomic_inc(&chip->wq_processing); /* don't schedule new work */ cancel_delayed_work_sync(&chip->work); kfree(chip); } @@ -89,6 +88,7 @@ int snd_ak4113_create(struct snd_card *card, ak4113_read_t *read, chip->write = write; chip->private_data = private_data; INIT_DELAYED_WORK(&chip->work, ak4113_stats); + atomic_set(&chip->wq_processing, 0);
for (reg = 0; reg < AK4113_WRITABLE_REGS ; reg++) chip->regmap[reg] = pgm[reg]; @@ -139,13 +139,11 @@ static void ak4113_init_regs(struct ak4113 *chip)
void snd_ak4113_reinit(struct ak4113 *chip) { - chip->init = 1; - mb(); - flush_delayed_work(&chip->work); + if (atomic_inc_return(&chip->wq_processing) == 1) + cancel_delayed_work_sync(&chip->work); ak4113_init_regs(chip); /* bring up statistics / event queing */ - chip->init = 0; - if (chip->kctls[0]) + if (atomic_dec_and_test(&chip->wq_processing)) schedule_delayed_work(&chip->work, HZ / 10); } EXPORT_SYMBOL_GPL(snd_ak4113_reinit); @@ -632,8 +630,9 @@ static void ak4113_stats(struct work_struct *work) { struct ak4113 *chip = container_of(work, struct ak4113, work.work);
- if (!chip->init) + if (atomic_inc_return(&chip->wq_processing) == 1) snd_ak4113_check_rate_and_errors(chip, chip->check_flags);
- schedule_delayed_work(&chip->work, HZ / 10); + if (atomic_dec_and_test(&chip->wq_processing)) + schedule_delayed_work(&chip->work, HZ / 10); } diff --git a/sound/i2c/other/ak4114.c b/sound/i2c/other/ak4114.c index c7f56339415d..b70e6eccbd03 100644 --- a/sound/i2c/other/ak4114.c +++ b/sound/i2c/other/ak4114.c @@ -66,8 +66,7 @@ static void reg_dump(struct ak4114 *ak4114)
static void snd_ak4114_free(struct ak4114 *chip) { - chip->init = 1; /* don't schedule new work */ - mb(); + atomic_inc(&chip->wq_processing); /* don't schedule new work */ cancel_delayed_work_sync(&chip->work); kfree(chip); } @@ -100,6 +99,7 @@ int snd_ak4114_create(struct snd_card *card, chip->write = write; chip->private_data = private_data; INIT_DELAYED_WORK(&chip->work, ak4114_stats); + atomic_set(&chip->wq_processing, 0);
for (reg = 0; reg < 6; reg++) chip->regmap[reg] = pgm[reg]; @@ -152,13 +152,11 @@ static void ak4114_init_regs(struct ak4114 *chip)
void snd_ak4114_reinit(struct ak4114 *chip) { - chip->init = 1; - mb(); - flush_delayed_work(&chip->work); + if (atomic_inc_return(&chip->wq_processing) == 1) + cancel_delayed_work_sync(&chip->work); ak4114_init_regs(chip); /* bring up statistics / event queing */ - chip->init = 0; - if (chip->kctls[0]) + if (atomic_dec_and_test(&chip->wq_processing)) schedule_delayed_work(&chip->work, HZ / 10); }
@@ -612,10 +610,10 @@ static void ak4114_stats(struct work_struct *work) { struct ak4114 *chip = container_of(work, struct ak4114, work.work);
- if (!chip->init) + if (atomic_inc_return(&chip->wq_processing) == 1) snd_ak4114_check_rate_and_errors(chip, chip->check_flags); - - schedule_delayed_work(&chip->work, HZ / 10); + if (atomic_dec_and_test(&chip->wq_processing)) + schedule_delayed_work(&chip->work, HZ / 10); }
EXPORT_SYMBOL(snd_ak4114_create);