This is a note to let you know that I've just added the patch titled ALSA: oss: Use kvzalloc() for local buffer allocations to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: alsa-oss-use-kvzalloc-for-local-buffer-allocations.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 65766ee0bf7fe8b3be80e2e1c3ef54ad59b29476 Mon Sep 17 00:00:00 2001 From: Takashi Iwai <tiwai@xxxxxxx> Date: Fri, 9 Nov 2018 11:59:45 +0100 Subject: ALSA: oss: Use kvzalloc() for local buffer allocations From: Takashi Iwai <tiwai@xxxxxxx> commit 65766ee0bf7fe8b3be80e2e1c3ef54ad59b29476 upstream. PCM OSS layer may allocate a few temporary buffers, one for the core read/write and another for the conversions via plugins. Currently both are allocated via vmalloc(). But as the allocation size is equivalent with the PCM period size, the required size might be quite small, depending on the application. This patch replaces these vmalloc() calls with kvzalloc() for covering small period sizes better. Also, we use "z"-alloc variant here for addressing the possible uninitialized access reported by syzkaller. Reported-by: syzbot+1cb36954e127c98dd037@xxxxxxxxxxxxxxxxxxxxxxxxx Cc: <stable@xxxxxxxxxxxxxxx> Signed-off-by: Takashi Iwai <tiwai@xxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- sound/core/oss/pcm_oss.c | 6 +++--- sound/core/oss/pcm_plugin.c | 6 +++--- 2 files changed, 6 insertions(+), 6 deletions(-) --- a/sound/core/oss/pcm_oss.c +++ b/sound/core/oss/pcm_oss.c @@ -1073,8 +1073,8 @@ static int snd_pcm_oss_change_params_loc runtime->oss.channels = params_channels(params); runtime->oss.rate = params_rate(params); - vfree(runtime->oss.buffer); - runtime->oss.buffer = vmalloc(runtime->oss.period_bytes); + kvfree(runtime->oss.buffer); + runtime->oss.buffer = kvzalloc(runtime->oss.period_bytes, GFP_KERNEL); if (!runtime->oss.buffer) { err = -ENOMEM; goto failure; @@ -2380,7 +2380,7 @@ static void snd_pcm_oss_release_substrea { struct snd_pcm_runtime *runtime; runtime = substream->runtime; - vfree(runtime->oss.buffer); + kvfree(runtime->oss.buffer); runtime->oss.buffer = NULL; #ifdef CONFIG_SND_PCM_OSS_PLUGINS snd_pcm_oss_plugin_clear(substream); --- a/sound/core/oss/pcm_plugin.c +++ b/sound/core/oss/pcm_plugin.c @@ -66,8 +66,8 @@ static int snd_pcm_plugin_alloc(struct s return -ENXIO; size /= 8; if (plugin->buf_frames < frames) { - vfree(plugin->buf); - plugin->buf = vmalloc(size); + kvfree(plugin->buf); + plugin->buf = kvzalloc(size, GFP_KERNEL); plugin->buf_frames = frames; } if (!plugin->buf) { @@ -191,7 +191,7 @@ int snd_pcm_plugin_free(struct snd_pcm_p if (plugin->private_free) plugin->private_free(plugin); kfree(plugin->buf_channels); - vfree(plugin->buf); + kvfree(plugin->buf); kfree(plugin); return 0; } Patches currently in stable-queue which might be from tiwai@xxxxxxx are queue-4.9/alsa-oss-use-kvzalloc-for-local-buffer-allocations.patch