summaryrefslogtreecommitdiff
path: root/include/sound
diff options
context:
space:
mode:
authorKaiChieh Chuang <kaichieh.chuang@mediatek.com>2019-03-07 02:51:09 +0300
committerMark Brown <broonie@kernel.org>2019-03-18 14:19:00 +0300
commitbbfaa7d36c1eb465f120f2a3dfe25c1fe022195d (patch)
tree91434b5cb4e9663a37fc000cec72351cd66e4ba7 /include/sound
parent2944d29d7c89573f9aa47083d105ff0243d5a125 (diff)
downloadlinux-bbfaa7d36c1eb465f120f2a3dfe25c1fe022195d.tar.xz
ASoC: dpcm: prevent snd_soc_dpcm use after free
The dpcm get from fe_clients/be_clients may be free before use Add a spin lock at snd_soc_card level, to protect the dpcm instance. The lock may be used in atomic context, so use spin lock. possible race condition between void dpcm_be_disconnect( ... list_del(&dpcm->list_be); list_del(&dpcm->list_fe); kfree(dpcm); ... and for_each_dpcm_fe() for_each_dpcm_be*() race condition example Thread 1: snd_soc_dapm_mixer_update_power() -> soc_dpcm_runtime_update() -> dpcm_be_disconnect() -> kfree(dpcm); Thread 2: dpcm_fe_dai_trigger() -> dpcm_be_dai_trigger() -> snd_soc_dpcm_can_be_free_stop() -> if (dpcm->fe == fe) Excpetion Scenario: two FE link to same BE FE1 -> BE FE2 -> Thread 1: switch of mixer between FE2 -> BE Thread 2: pcm_stop FE1 Exception: Unable to handle kernel paging request at virtual address dead0000000000e0 pc=<> [<ffffff8960e2cd10>] dpcm_be_dai_trigger+0x29c/0x47c sound/soc/soc-pcm.c:3226 if (dpcm->fe == fe) lr=<> [<ffffff8960e2f694>] dpcm_fe_dai_do_trigger+0x94/0x26c Backtrace: [<ffffff89602dba80>] notify_die+0x68/0xb8 [<ffffff896028c7dc>] die+0x118/0x2a8 [<ffffff89602a2f84>] __do_kernel_fault+0x13c/0x14c [<ffffff89602a27f4>] do_translation_fault+0x64/0xa0 [<ffffff8960280cf8>] do_mem_abort+0x4c/0xd0 [<ffffff8960282ad0>] el1_da+0x24/0x40 [<ffffff8960e2cd10>] dpcm_be_dai_trigger+0x29c/0x47c [<ffffff8960e2f694>] dpcm_fe_dai_do_trigger+0x94/0x26c [<ffffff8960e2edec>] dpcm_fe_dai_trigger+0x3c/0x44 [<ffffff8960de5588>] snd_pcm_do_stop+0x50/0x5c [<ffffff8960dded24>] snd_pcm_action+0xb4/0x13c [<ffffff8960ddfdb4>] snd_pcm_drop+0xa0/0x128 [<ffffff8960de69bc>] snd_pcm_common_ioctl+0x9d8/0x30f0 [<ffffff8960de1cac>] snd_pcm_ioctl_compat+0x29c/0x2f14 [<ffffff89604c9d60>] compat_SyS_ioctl+0x128/0x244 [<ffffff8960283740>] el0_svc_naked+0x34/0x38 [<ffffffffffffffff>] 0xffffffffffffffff Signed-off-by: KaiChieh Chuang <kaichieh.chuang@mediatek.com> Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'include/sound')
-rw-r--r--include/sound/soc.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/include/sound/soc.h b/include/sound/soc.h
index eb7db605955b..1e2be35ed36f 100644
--- a/include/sound/soc.h
+++ b/include/sound/soc.h
@@ -1083,6 +1083,8 @@ struct snd_soc_card {
struct mutex mutex;
struct mutex dapm_mutex;
+ spinlock_t dpcm_lock;
+
bool instantiated;
bool topology_shortname_created;