--- /dev/null
+From foo@baz Fri May 13 10:30:48 AM CEST 2022
+From: Ovidiu Panait <ovidiu.panait@windriver.com>
+Date: Fri, 13 May 2022 11:00:18 +0300
+Subject: ALSA: pcm: Fix potential AB/BA lock with buffer_mutex and mmap_lock
+To: stable@vger.kernel.org
+Cc: Takashi Iwai <tiwai@suse.de>, syzbot+6e5c88838328e99c7e1c@syzkaller.appspotmail.com, Ovidiu Panait <ovidiu.panait@windriver.com>
+Message-ID: <20220513080018.1302825-5-ovidiu.panait@windriver.com>
+
+From: Takashi Iwai <tiwai@suse.de>
+
+commit bc55cfd5718c7c23e5524582e9fa70b4d10f2433 upstream.
+
+syzbot caught a potential deadlock between the PCM
+runtime->buffer_mutex and the mm->mmap_lock. It was brought by the
+recent fix to cover the racy read/write and other ioctls, and in that
+commit, I overlooked a (hopefully only) corner case that may take the
+revert lock, namely, the OSS mmap. The OSS mmap operation
+exceptionally allows to re-configure the parameters inside the OSS
+mmap syscall, where mm->mmap_mutex is already held. Meanwhile, the
+copy_from/to_user calls at read/write operations also take the
+mm->mmap_lock internally, hence it may lead to a AB/BA deadlock.
+
+A similar problem was already seen in the past and we fixed it with a
+refcount (in commit b248371628aa). The former fix covered only the
+call paths with OSS read/write and OSS ioctls, while we need to cover
+the concurrent access via both ALSA and OSS APIs now.
+
+This patch addresses the problem above by replacing the buffer_mutex
+lock in the read/write operations with a refcount similar as we've
+used for OSS. The new field, runtime->buffer_accessing, keeps the
+number of concurrent read/write operations. Unlike the former
+buffer_mutex protection, this protects only around the
+copy_from/to_user() calls; the other codes are basically protected by
+the PCM stream lock. The refcount can be a negative, meaning blocked
+by the ioctls. If a negative value is seen, the read/write aborts
+with -EBUSY. In the ioctl side, OTOH, they check this refcount, too,
+and set to a negative value for blocking unless it's already being
+accessed.
+
+Reported-by: syzbot+6e5c88838328e99c7e1c@syzkaller.appspotmail.com
+Fixes: dca947d4d26d ("ALSA: pcm: Fix races among concurrent read/write and buffer changes")
+Cc: <stable@vger.kernel.org>
+Link: https://lore.kernel.org/r/000000000000381a0d05db622a81@google.com
+Link: https://lore.kernel.org/r/20220330120903.4738-1-tiwai@suse.de
+Signed-off-by: Takashi Iwai <tiwai@suse.de>
+[OP: backport to 4.19: adjusted context]
+Signed-off-by: Ovidiu Panait <ovidiu.panait@windriver.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ include/sound/pcm.h | 1 +
+ sound/core/pcm.c | 1 +
+ sound/core/pcm_lib.c | 9 +++++----
+ sound/core/pcm_native.c | 39 ++++++++++++++++++++++++++++++++-------
+ 4 files changed, 39 insertions(+), 11 deletions(-)
+
+--- a/include/sound/pcm.h
++++ b/include/sound/pcm.h
+@@ -405,6 +405,7 @@ struct snd_pcm_runtime {
+ wait_queue_head_t tsleep; /* transfer sleep */
+ struct fasync_struct *fasync;
+ struct mutex buffer_mutex; /* protect for buffer changes */
++ atomic_t buffer_accessing; /* >0: in r/w operation, <0: blocked */
+
+ /* -- private section -- */
+ void *private_data;
+--- a/sound/core/pcm.c
++++ b/sound/core/pcm.c
+@@ -1032,6 +1032,7 @@ int snd_pcm_attach_substream(struct snd_
+
+ runtime->status->state = SNDRV_PCM_STATE_OPEN;
+ mutex_init(&runtime->buffer_mutex);
++ atomic_set(&runtime->buffer_accessing, 0);
+
+ substream->runtime = runtime;
+ substream->private_data = pcm->private_data;
+--- a/sound/core/pcm_lib.c
++++ b/sound/core/pcm_lib.c
+@@ -1876,11 +1876,9 @@ static int wait_for_avail(struct snd_pcm
+ if (avail >= runtime->twake)
+ break;
+ snd_pcm_stream_unlock_irq(substream);
+- mutex_unlock(&runtime->buffer_mutex);
+
+ tout = schedule_timeout(wait_time);
+
+- mutex_lock(&runtime->buffer_mutex);
+ snd_pcm_stream_lock_irq(substream);
+ set_current_state(TASK_INTERRUPTIBLE);
+ switch (runtime->status->state) {
+@@ -2174,7 +2172,6 @@ snd_pcm_sframes_t __snd_pcm_lib_xfer(str
+
+ nonblock = !!(substream->f_flags & O_NONBLOCK);
+
+- mutex_lock(&runtime->buffer_mutex);
+ snd_pcm_stream_lock_irq(substream);
+ err = pcm_accessible_state(runtime);
+ if (err < 0)
+@@ -2224,10 +2221,15 @@ snd_pcm_sframes_t __snd_pcm_lib_xfer(str
+ snd_pcm_stream_unlock_irq(substream);
+ return -EINVAL;
+ }
++ if (!atomic_inc_unless_negative(&runtime->buffer_accessing)) {
++ err = -EBUSY;
++ goto _end_unlock;
++ }
+ snd_pcm_stream_unlock_irq(substream);
+ err = writer(substream, appl_ofs, data, offset, frames,
+ transfer);
+ snd_pcm_stream_lock_irq(substream);
++ atomic_dec(&runtime->buffer_accessing);
+ if (err < 0)
+ goto _end_unlock;
+ err = pcm_accessible_state(runtime);
+@@ -2257,7 +2259,6 @@ snd_pcm_sframes_t __snd_pcm_lib_xfer(str
+ if (xfer > 0 && err >= 0)
+ snd_pcm_update_state(substream, runtime);
+ snd_pcm_stream_unlock_irq(substream);
+- mutex_unlock(&runtime->buffer_mutex);
+ return xfer > 0 ? (snd_pcm_sframes_t)xfer : err;
+ }
+ EXPORT_SYMBOL(__snd_pcm_lib_xfer);
+--- a/sound/core/pcm_native.c
++++ b/sound/core/pcm_native.c
+@@ -666,6 +666,24 @@ static int snd_pcm_hw_params_choose(stru
+ return 0;
+ }
+
++/* acquire buffer_mutex; if it's in r/w operation, return -EBUSY, otherwise
++ * block the further r/w operations
++ */
++static int snd_pcm_buffer_access_lock(struct snd_pcm_runtime *runtime)
++{
++ if (!atomic_dec_unless_positive(&runtime->buffer_accessing))
++ return -EBUSY;
++ mutex_lock(&runtime->buffer_mutex);
++ return 0; /* keep buffer_mutex, unlocked by below */
++}
++
++/* release buffer_mutex and clear r/w access flag */
++static void snd_pcm_buffer_access_unlock(struct snd_pcm_runtime *runtime)
++{
++ mutex_unlock(&runtime->buffer_mutex);
++ atomic_inc(&runtime->buffer_accessing);
++}
++
+ #if IS_ENABLED(CONFIG_SND_PCM_OSS)
+ #define is_oss_stream(substream) ((substream)->oss.oss)
+ #else
+@@ -676,14 +694,16 @@ static int snd_pcm_hw_params(struct snd_
+ struct snd_pcm_hw_params *params)
+ {
+ struct snd_pcm_runtime *runtime;
+- int err = 0, usecs;
++ int err, usecs;
+ unsigned int bits;
+ snd_pcm_uframes_t frames;
+
+ if (PCM_RUNTIME_CHECK(substream))
+ return -ENXIO;
+ runtime = substream->runtime;
+- mutex_lock(&runtime->buffer_mutex);
++ err = snd_pcm_buffer_access_lock(runtime);
++ if (err < 0)
++ return err;
+ snd_pcm_stream_lock_irq(substream);
+ switch (runtime->status->state) {
+ case SNDRV_PCM_STATE_OPEN:
+@@ -788,7 +808,7 @@ static int snd_pcm_hw_params(struct snd_
+ substream->ops->hw_free(substream);
+ }
+ unlock:
+- mutex_unlock(&runtime->buffer_mutex);
++ snd_pcm_buffer_access_unlock(runtime);
+ return err;
+ }
+
+@@ -821,7 +841,9 @@ static int snd_pcm_hw_free(struct snd_pc
+ if (PCM_RUNTIME_CHECK(substream))
+ return -ENXIO;
+ runtime = substream->runtime;
+- mutex_lock(&runtime->buffer_mutex);
++ result = snd_pcm_buffer_access_lock(runtime);
++ if (result < 0)
++ return result;
+ snd_pcm_stream_lock_irq(substream);
+ switch (runtime->status->state) {
+ case SNDRV_PCM_STATE_SETUP:
+@@ -841,7 +863,7 @@ static int snd_pcm_hw_free(struct snd_pc
+ snd_pcm_set_state(substream, SNDRV_PCM_STATE_OPEN);
+ pm_qos_remove_request(&substream->latency_pm_qos_req);
+ unlock:
+- mutex_unlock(&runtime->buffer_mutex);
++ snd_pcm_buffer_access_unlock(runtime);
+ return result;
+ }
+
+@@ -1208,12 +1230,15 @@ static int snd_pcm_action_nonatomic(cons
+ int res;
+
+ down_read(&snd_pcm_link_rwsem);
+- mutex_lock(&substream->runtime->buffer_mutex);
++ res = snd_pcm_buffer_access_lock(substream->runtime);
++ if (res < 0)
++ goto unlock;
+ if (snd_pcm_stream_linked(substream))
+ res = snd_pcm_action_group(ops, substream, state, 0);
+ else
+ res = snd_pcm_action_single(ops, substream, state);
+- mutex_unlock(&substream->runtime->buffer_mutex);
++ snd_pcm_buffer_access_unlock(substream->runtime);
++ unlock:
+ up_read(&snd_pcm_link_rwsem);
+ return res;
+ }
--- /dev/null
+From foo@baz Fri May 13 10:30:48 AM CEST 2022
+From: Ovidiu Panait <ovidiu.panait@windriver.com>
+Date: Fri, 13 May 2022 11:00:14 +0300
+Subject: ALSA: pcm: Fix races among concurrent hw_params and hw_free calls
+To: stable@vger.kernel.org
+Cc: Takashi Iwai <tiwai@suse.de>, Hu Jiahui <kirin.say@gmail.com>, Jaroslav Kysela <perex@perex.cz>, Ovidiu Panait <ovidiu.panait@windriver.com>
+Message-ID: <20220513080018.1302825-1-ovidiu.panait@windriver.com>
+
+From: Takashi Iwai <tiwai@suse.de>
+
+commit 92ee3c60ec9fe64404dc035e7c41277d74aa26cb upstream.
+
+Currently we have neither proper check nor protection against the
+concurrent calls of PCM hw_params and hw_free ioctls, which may result
+in a UAF. Since the existing PCM stream lock can't be used for
+protecting the whole ioctl operations, we need a new mutex to protect
+those racy calls.
+
+This patch introduced a new mutex, runtime->buffer_mutex, and applies
+it to both hw_params and hw_free ioctl code paths. Along with it, the
+both functions are slightly modified (the mmap_count check is moved
+into the state-check block) for code simplicity.
+
+Reported-by: Hu Jiahui <kirin.say@gmail.com>
+Cc: <stable@vger.kernel.org>
+Reviewed-by: Jaroslav Kysela <perex@perex.cz>
+Link: https://lore.kernel.org/r/20220322170720.3529-2-tiwai@suse.de
+Signed-off-by: Takashi Iwai <tiwai@suse.de>
+[OP: backport to 4.19: adjusted context]
+Signed-off-by: Ovidiu Panait <ovidiu.panait@windriver.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ include/sound/pcm.h | 1
+ sound/core/pcm.c | 2 +
+ sound/core/pcm_native.c | 55 +++++++++++++++++++++++++++++++-----------------
+ 3 files changed, 39 insertions(+), 19 deletions(-)
+
+--- a/include/sound/pcm.h
++++ b/include/sound/pcm.h
+@@ -404,6 +404,7 @@ struct snd_pcm_runtime {
+ wait_queue_head_t sleep; /* poll sleep */
+ wait_queue_head_t tsleep; /* transfer sleep */
+ struct fasync_struct *fasync;
++ struct mutex buffer_mutex; /* protect for buffer changes */
+
+ /* -- private section -- */
+ void *private_data;
+--- a/sound/core/pcm.c
++++ b/sound/core/pcm.c
+@@ -1031,6 +1031,7 @@ int snd_pcm_attach_substream(struct snd_
+ init_waitqueue_head(&runtime->tsleep);
+
+ runtime->status->state = SNDRV_PCM_STATE_OPEN;
++ mutex_init(&runtime->buffer_mutex);
+
+ substream->runtime = runtime;
+ substream->private_data = pcm->private_data;
+@@ -1062,6 +1063,7 @@ void snd_pcm_detach_substream(struct snd
+ substream->runtime = NULL;
+ if (substream->timer)
+ spin_unlock_irq(&substream->timer->lock);
++ mutex_destroy(&runtime->buffer_mutex);
+ kfree(runtime);
+ put_pid(substream->pid);
+ substream->pid = NULL;
+--- a/sound/core/pcm_native.c
++++ b/sound/core/pcm_native.c
+@@ -666,33 +666,40 @@ static int snd_pcm_hw_params_choose(stru
+ return 0;
+ }
+
++#if IS_ENABLED(CONFIG_SND_PCM_OSS)
++#define is_oss_stream(substream) ((substream)->oss.oss)
++#else
++#define is_oss_stream(substream) false
++#endif
++
+ static int snd_pcm_hw_params(struct snd_pcm_substream *substream,
+ struct snd_pcm_hw_params *params)
+ {
+ struct snd_pcm_runtime *runtime;
+- int err, usecs;
++ int err = 0, usecs;
+ unsigned int bits;
+ snd_pcm_uframes_t frames;
+
+ if (PCM_RUNTIME_CHECK(substream))
+ return -ENXIO;
+ runtime = substream->runtime;
++ mutex_lock(&runtime->buffer_mutex);
+ snd_pcm_stream_lock_irq(substream);
+ switch (runtime->status->state) {
+ case SNDRV_PCM_STATE_OPEN:
+ case SNDRV_PCM_STATE_SETUP:
+ case SNDRV_PCM_STATE_PREPARED:
++ if (!is_oss_stream(substream) &&
++ atomic_read(&substream->mmap_count))
++ err = -EBADFD;
+ break;
+ default:
+- snd_pcm_stream_unlock_irq(substream);
+- return -EBADFD;
++ err = -EBADFD;
++ break;
+ }
+ snd_pcm_stream_unlock_irq(substream);
+-#if IS_ENABLED(CONFIG_SND_PCM_OSS)
+- if (!substream->oss.oss)
+-#endif
+- if (atomic_read(&substream->mmap_count))
+- return -EBADFD;
++ if (err)
++ goto unlock;
+
+ params->rmask = ~0U;
+ err = snd_pcm_hw_refine(substream, params);
+@@ -769,14 +776,19 @@ static int snd_pcm_hw_params(struct snd_
+ if ((usecs = period_to_usecs(runtime)) >= 0)
+ pm_qos_add_request(&substream->latency_pm_qos_req,
+ PM_QOS_CPU_DMA_LATENCY, usecs);
+- return 0;
++ err = 0;
+ _error:
+- /* hardware might be unusable from this time,
+- so we force application to retry to set
+- the correct hardware parameter settings */
+- snd_pcm_set_state(substream, SNDRV_PCM_STATE_OPEN);
+- if (substream->ops->hw_free != NULL)
+- substream->ops->hw_free(substream);
++ if (err) {
++ /* hardware might be unusable from this time,
++ * so we force application to retry to set
++ * the correct hardware parameter settings
++ */
++ snd_pcm_set_state(substream, SNDRV_PCM_STATE_OPEN);
++ if (substream->ops->hw_free != NULL)
++ substream->ops->hw_free(substream);
++ }
++ unlock:
++ mutex_unlock(&runtime->buffer_mutex);
+ return err;
+ }
+
+@@ -809,22 +821,27 @@ static int snd_pcm_hw_free(struct snd_pc
+ if (PCM_RUNTIME_CHECK(substream))
+ return -ENXIO;
+ runtime = substream->runtime;
++ mutex_lock(&runtime->buffer_mutex);
+ snd_pcm_stream_lock_irq(substream);
+ switch (runtime->status->state) {
+ case SNDRV_PCM_STATE_SETUP:
+ case SNDRV_PCM_STATE_PREPARED:
++ if (atomic_read(&substream->mmap_count))
++ result = -EBADFD;
+ break;
+ default:
+- snd_pcm_stream_unlock_irq(substream);
+- return -EBADFD;
++ result = -EBADFD;
++ break;
+ }
+ snd_pcm_stream_unlock_irq(substream);
+- if (atomic_read(&substream->mmap_count))
+- return -EBADFD;
++ if (result)
++ goto unlock;
+ if (substream->ops->hw_free)
+ result = substream->ops->hw_free(substream);
+ snd_pcm_set_state(substream, SNDRV_PCM_STATE_OPEN);
+ pm_qos_remove_request(&substream->latency_pm_qos_req);
++ unlock:
++ mutex_unlock(&runtime->buffer_mutex);
+ return result;
+ }
+
--- /dev/null
+From foo@baz Fri May 13 10:30:48 AM CEST 2022
+From: Ovidiu Panait <ovidiu.panait@windriver.com>
+Date: Fri, 13 May 2022 11:00:17 +0300
+Subject: ALSA: pcm: Fix races among concurrent prealloc proc writes
+To: stable@vger.kernel.org
+Cc: Takashi Iwai <tiwai@suse.de>, Jaroslav Kysela <perex@perex.cz>, Ovidiu Panait <ovidiu.panait@windriver.com>
+Message-ID: <20220513080018.1302825-4-ovidiu.panait@windriver.com>
+
+From: Takashi Iwai <tiwai@suse.de>
+
+commit 69534c48ba8ce552ce383b3dfdb271ffe51820c3 upstream.
+
+We have no protection against concurrent PCM buffer preallocation
+changes via proc files, and it may potentially lead to UAF or some
+weird problem. This patch applies the PCM open_mutex to the proc
+write operation for avoiding the racy proc writes and the PCM stream
+open (and further operations).
+
+Cc: <stable@vger.kernel.org>
+Reviewed-by: Jaroslav Kysela <perex@perex.cz>
+Link: https://lore.kernel.org/r/20220322170720.3529-5-tiwai@suse.de
+Signed-off-by: Takashi Iwai <tiwai@suse.de>
+[OP: backport to 4.19: adjusted context]
+Signed-off-by: Ovidiu Panait <ovidiu.panait@windriver.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ sound/core/pcm_memory.c | 11 +++++++----
+ 1 file changed, 7 insertions(+), 4 deletions(-)
+
+--- a/sound/core/pcm_memory.c
++++ b/sound/core/pcm_memory.c
+@@ -160,19 +160,20 @@ static void snd_pcm_lib_preallocate_proc
+ size_t size;
+ struct snd_dma_buffer new_dmab;
+
++ mutex_lock(&substream->pcm->open_mutex);
+ if (substream->runtime) {
+ buffer->error = -EBUSY;
+- return;
++ goto unlock;
+ }
+ if (!snd_info_get_line(buffer, line, sizeof(line))) {
+ snd_info_get_str(str, line, sizeof(str));
+ size = simple_strtoul(str, NULL, 10) * 1024;
+ if ((size != 0 && size < 8192) || size > substream->dma_max) {
+ buffer->error = -EINVAL;
+- return;
++ goto unlock;
+ }
+ if (substream->dma_buffer.bytes == size)
+- return;
++ goto unlock;
+ memset(&new_dmab, 0, sizeof(new_dmab));
+ new_dmab.dev = substream->dma_buffer.dev;
+ if (size > 0) {
+@@ -180,7 +181,7 @@ static void snd_pcm_lib_preallocate_proc
+ substream->dma_buffer.dev.dev,
+ size, &new_dmab) < 0) {
+ buffer->error = -ENOMEM;
+- return;
++ goto unlock;
+ }
+ substream->buffer_bytes_max = size;
+ } else {
+@@ -192,6 +193,8 @@ static void snd_pcm_lib_preallocate_proc
+ } else {
+ buffer->error = -EINVAL;
+ }
++ unlock:
++ mutex_unlock(&substream->pcm->open_mutex);
+ }
+
+ static inline void preallocate_info_init(struct snd_pcm_substream *substream)
--- /dev/null
+From foo@baz Fri May 13 10:30:48 AM CEST 2022
+From: Ovidiu Panait <ovidiu.panait@windriver.com>
+Date: Fri, 13 May 2022 11:00:16 +0300
+Subject: ALSA: pcm: Fix races among concurrent prepare and hw_params/hw_free calls
+To: stable@vger.kernel.org
+Cc: Takashi Iwai <tiwai@suse.de>, Jaroslav Kysela <perex@perex.cz>, Ovidiu Panait <ovidiu.panait@windriver.com>
+Message-ID: <20220513080018.1302825-3-ovidiu.panait@windriver.com>
+
+From: Takashi Iwai <tiwai@suse.de>
+
+commit 3c3201f8c7bb77eb53b08a3ca8d9a4ddc500b4c0 upstream.
+
+Like the previous fixes to hw_params and hw_free ioctl races, we need
+to paper over the concurrent prepare ioctl calls against hw_params and
+hw_free, too.
+
+This patch implements the locking with the existing
+runtime->buffer_mutex for prepare ioctls. Unlike the previous case
+for snd_pcm_hw_hw_params() and snd_pcm_hw_free(), snd_pcm_prepare() is
+performed to the linked streams, hence the lock can't be applied
+simply on the top. For tracking the lock in each linked substream, we
+modify snd_pcm_action_group() slightly and apply the buffer_mutex for
+the case stream_lock=false (formerly there was no lock applied)
+there.
+
+Cc: <stable@vger.kernel.org>
+Reviewed-by: Jaroslav Kysela <perex@perex.cz>
+Link: https://lore.kernel.org/r/20220322170720.3529-4-tiwai@suse.de
+Signed-off-by: Takashi Iwai <tiwai@suse.de>
+[OP: backport to 4.19: adjusted context]
+Signed-off-by: Ovidiu Panait <ovidiu.panait@windriver.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ sound/core/pcm_native.c | 32 ++++++++++++++++++--------------
+ 1 file changed, 18 insertions(+), 14 deletions(-)
+
+--- a/sound/core/pcm_native.c
++++ b/sound/core/pcm_native.c
+@@ -1078,15 +1078,17 @@ struct action_ops {
+ */
+ static int snd_pcm_action_group(const struct action_ops *ops,
+ struct snd_pcm_substream *substream,
+- int state, int do_lock)
++ int state, int stream_lock)
+ {
+ struct snd_pcm_substream *s = NULL;
+ struct snd_pcm_substream *s1;
+ int res = 0, depth = 1;
+
+ snd_pcm_group_for_each_entry(s, substream) {
+- if (do_lock && s != substream) {
+- if (s->pcm->nonatomic)
++ if (s != substream) {
++ if (!stream_lock)
++ mutex_lock_nested(&s->runtime->buffer_mutex, depth);
++ else if (s->pcm->nonatomic)
+ mutex_lock_nested(&s->self_group.mutex, depth);
+ else
+ spin_lock_nested(&s->self_group.lock, depth);
+@@ -1114,18 +1116,18 @@ static int snd_pcm_action_group(const st
+ ops->post_action(s, state);
+ }
+ _unlock:
+- if (do_lock) {
+- /* unlock streams */
+- snd_pcm_group_for_each_entry(s1, substream) {
+- if (s1 != substream) {
+- if (s1->pcm->nonatomic)
+- mutex_unlock(&s1->self_group.mutex);
+- else
+- spin_unlock(&s1->self_group.lock);
+- }
+- if (s1 == s) /* end */
+- break;
++ /* unlock streams */
++ snd_pcm_group_for_each_entry(s1, substream) {
++ if (s1 != substream) {
++ if (!stream_lock)
++ mutex_unlock(&s1->runtime->buffer_mutex);
++ else if (s1->pcm->nonatomic)
++ mutex_unlock(&s1->self_group.mutex);
++ else
++ spin_unlock(&s1->self_group.lock);
+ }
++ if (s1 == s) /* end */
++ break;
+ }
+ return res;
+ }
+@@ -1206,10 +1208,12 @@ static int snd_pcm_action_nonatomic(cons
+ int res;
+
+ down_read(&snd_pcm_link_rwsem);
++ mutex_lock(&substream->runtime->buffer_mutex);
+ if (snd_pcm_stream_linked(substream))
+ res = snd_pcm_action_group(ops, substream, state, 0);
+ else
+ res = snd_pcm_action_single(ops, substream, state);
++ mutex_unlock(&substream->runtime->buffer_mutex);
+ up_read(&snd_pcm_link_rwsem);
+ return res;
+ }
--- /dev/null
+From foo@baz Fri May 13 10:30:48 AM CEST 2022
+From: Ovidiu Panait <ovidiu.panait@windriver.com>
+Date: Fri, 13 May 2022 11:00:15 +0300
+Subject: ALSA: pcm: Fix races among concurrent read/write and buffer changes
+To: stable@vger.kernel.org
+Cc: Takashi Iwai <tiwai@suse.de>, Jaroslav Kysela <perex@perex.cz>, Ovidiu Panait <ovidiu.panait@windriver.com>
+Message-ID: <20220513080018.1302825-2-ovidiu.panait@windriver.com>
+
+From: Takashi Iwai <tiwai@suse.de>
+
+commit dca947d4d26dbf925a64a6cfb2ddbc035e831a3d upstream.
+
+In the current PCM design, the read/write syscalls (as well as the
+equivalent ioctls) are allowed before the PCM stream is running, that
+is, at PCM PREPARED state. Meanwhile, we also allow to re-issue
+hw_params and hw_free ioctl calls at the PREPARED state that may
+change or free the buffers, too. The problem is that there is no
+protection against those mix-ups.
+
+This patch applies the previously introduced runtime->buffer_mutex to
+the read/write operations so that the concurrent hw_params or hw_free
+call can no longer interfere during the operation. The mutex is
+unlocked before scheduling, so we don't take it too long.
+
+Cc: <stable@vger.kernel.org>
+Reviewed-by: Jaroslav Kysela <perex@perex.cz>
+Link: https://lore.kernel.org/r/20220322170720.3529-3-tiwai@suse.de
+Signed-off-by: Takashi Iwai <tiwai@suse.de>
+Signed-off-by: Ovidiu Panait <ovidiu.panait@windriver.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ sound/core/pcm_lib.c | 4 ++++
+ 1 file changed, 4 insertions(+)
+
+--- a/sound/core/pcm_lib.c
++++ b/sound/core/pcm_lib.c
+@@ -1876,9 +1876,11 @@ static int wait_for_avail(struct snd_pcm
+ if (avail >= runtime->twake)
+ break;
+ snd_pcm_stream_unlock_irq(substream);
++ mutex_unlock(&runtime->buffer_mutex);
+
+ tout = schedule_timeout(wait_time);
+
++ mutex_lock(&runtime->buffer_mutex);
+ snd_pcm_stream_lock_irq(substream);
+ set_current_state(TASK_INTERRUPTIBLE);
+ switch (runtime->status->state) {
+@@ -2172,6 +2174,7 @@ snd_pcm_sframes_t __snd_pcm_lib_xfer(str
+
+ nonblock = !!(substream->f_flags & O_NONBLOCK);
+
++ mutex_lock(&runtime->buffer_mutex);
+ snd_pcm_stream_lock_irq(substream);
+ err = pcm_accessible_state(runtime);
+ if (err < 0)
+@@ -2254,6 +2257,7 @@ snd_pcm_sframes_t __snd_pcm_lib_xfer(str
+ if (xfer > 0 && err >= 0)
+ snd_pcm_update_state(substream, runtime);
+ snd_pcm_stream_unlock_irq(substream);
++ mutex_unlock(&runtime->buffer_mutex);
+ return xfer > 0 ? (snd_pcm_sframes_t)xfer : err;
+ }
+ EXPORT_SYMBOL(__snd_pcm_lib_xfer);
can-grcan-grcan_probe-fix-broken-system-id-check-for-errata-workaround-needs.patch
can-grcan-only-use-the-napi-poll-budget-for-rx.patch
bluetooth-fix-the-creation-of-hdev-name.patch
+alsa-pcm-fix-races-among-concurrent-hw_params-and-hw_free-calls.patch
+alsa-pcm-fix-races-among-concurrent-read-write-and-buffer-changes.patch
+alsa-pcm-fix-races-among-concurrent-prepare-and-hw_params-hw_free-calls.patch
+alsa-pcm-fix-races-among-concurrent-prealloc-proc-writes.patch
+alsa-pcm-fix-potential-ab-ba-lock-with-buffer_mutex-and-mmap_lock.patch
projects / thirdparty / kernel / stable-queue.git / commitdiff
