Commit 47c27c9c authored by Jaroslav Kysela's avatar Jaroslav Kysela Committed by Takashi Iwai
Browse files

ALSA: pcm: Improve the fix for race of buffer access at PCM OSS layer 



Handle the error code from snd_pcm_buffer_access_lock() in
snd_pcm_runtime_buffer_set_silence() function.

Found by Alexandros Panagiotou <apanagio@redhat.com>

Fixes: 93a81ca0 ("ALSA: pcm: Fix race of buffer access at PCM OSS layer")
Cc: stable@vger.kernel.org # 6.15
Signed-off-by: default avatarJaroslav Kysela <perex@perex.cz>
Link: https://patch.msgid.link/20260107213642.332954-1-perex@perex.cz


Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 9ed7a282

include/sound/pcm.h

+1 −1
Original line number Diff line number Diff line
@@ -1402,7 +1402,7 @@ int snd_pcm_lib_mmap_iomem(struct snd_pcm_substream *substream, struct vm_area_s 
#define snd_pcm_lib_mmap_iomem	NULL

#endif



void snd_pcm_runtime_buffer_set_silence(struct snd_pcm_runtime *runtime);

int snd_pcm_runtime_buffer_set_silence(struct snd_pcm_runtime *runtime);



/**

 * snd_pcm_limit_isa_dma_size - Get the max size fitting with ISA DMA transfer

sound/core/oss/pcm_oss.c

+3 −1
Original line number Diff line number Diff line
@@ -1074,7 +1074,9 @@ static int snd_pcm_oss_change_params_locked(struct snd_pcm_substream *substream) 
	runtime->oss.params = 0;

	runtime->oss.prepare = 1;

	runtime->oss.buffer_used = 0;

	snd_pcm_runtime_buffer_set_silence(runtime);

	err = snd_pcm_runtime_buffer_set_silence(runtime);

	if (err < 0)

		goto failure;



	runtime->oss.period_frames = snd_pcm_alsa_frames(substream, oss_period_size);

sound/core/pcm_native.c

+7 −2
Original line number Diff line number Diff line
@@ -730,13 +730,18 @@ static void snd_pcm_buffer_access_unlock(struct snd_pcm_runtime *runtime) 
}



/* fill the PCM buffer with the current silence format; called from pcm_oss.c */

void snd_pcm_runtime_buffer_set_silence(struct snd_pcm_runtime *runtime)

int snd_pcm_runtime_buffer_set_silence(struct snd_pcm_runtime *runtime)

{

	snd_pcm_buffer_access_lock(runtime);

	int err;



	err = snd_pcm_buffer_access_lock(runtime);

	if (err < 0)

		return err;

	if (runtime->dma_area)

		snd_pcm_format_set_silence(runtime->format, runtime->dma_area,

					   bytes_to_samples(runtime, runtime->dma_bytes));

	snd_pcm_buffer_access_unlock(runtime);

	return 0;

}

EXPORT_SYMBOL_GPL(snd_pcm_runtime_buffer_set_silence);