[PATCH v3] ASoC: SOF: Intel: Fix NULL ptr dereference when ENOMEM

[Ammar Faizi]

From: Ammar Faizi <ammarfaizi2 at gnuweeb.org>

Do not call snd_dma_free_pages() when snd_dma_alloc_pages() returns
-ENOMEM because it leads to a NULL pointer dereference bug.

The dmesg says:

  [ T1387] sof-audio-pci-intel-tgl 0000:00:1f.3: error: memory alloc failed: -12
  [ T1387] BUG: kernel NULL pointer dereference, address: 0000000000000000
  [ T1387] #PF: supervisor read access in kernel mode
  [ T1387] #PF: error_code(0x0000) - not-present page
  [ T1387] PGD 0 P4D 0
  [ T1387] Oops: 0000 [#1] PREEMPT SMP NOPTI
  [ T1387] CPU: 6 PID: 1387 Comm: alsa-sink-HDA A Tainted: G        W         5.17.0-rc4-superb-owl-00055-g80d47f5de5e3 #3 56590caeed02394520e20ca5a2059907eb2d5079
  [ T1387] Hardware name: HP HP Laptop 14s-dq2xxx/87FD, BIOS F.15 09/15/2021
  [ T1387] RIP: 0010:dma_free_noncontiguous+0x37/0x80
  [ T1387] Code: [... snip ...]
  [ T1387] RSP: 0000:ffffc90002b87770 EFLAGS: 00010246
  [ T1387] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
  [ T1387] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff888101db30d0
  [ T1387] RBP: 00000000fffffff4 R08: 0000000000000000 R09: 0000000000000000
  [ T1387] R10: 0000000000000000 R11: ffffc90002b874d0 R12: 0000000000000001
  [ T1387] R13: 0000000000058000 R14: ffff888105260c68 R15: ffff888105260828
  [ T1387] FS:  00007f42e2ffd640(0000) GS:ffff888466b80000(0000) knlGS:0000000000000000
  [ T1387] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  [ T1387] CR2: 0000000000000000 CR3: 000000014acf0003 CR4: 0000000000770ee0
  [ T1387] PKRU: 55555554
  [ T1387] Call Trace:
  [ T1387]  <TASK>
  [ T1387]  cl_stream_prepare+0x10a/0x120 [snd_sof_intel_hda_common 146addf995b9279ae7f509621078cccbe4f875e1]

  [... snip ...]

  [ T1387]  </TASK>

Cc: Daniel Baluta <daniel.baluta at nxp.com>
Cc: Jaroslav Kysela <perex at perex.cz>
Cc: Kai Vehmanen <kai.vehmanen at linux.intel.com>
Cc: Keyon Jie <yang.jie at linux.intel.com>
Cc: Liam Girdwood <lgirdwood at gmail.com>
Cc: Mark Brown <broonie at kernel.org>
Cc: Peter Ujfalusi <peter.ujfalusi at linux.intel.com>
Cc: Pierre-Louis Bossart <pierre-louis.bossart at linux.intel.com>
Cc: Rander Wang <rander.wang at intel.com>
Cc: Ranjani Sridharan <ranjani.sridharan at linux.intel.com>
Cc: Takashi Iwai <tiwai at suse.com>
Fixes: d16046ffa6de040bf580a64d5f4d0aa18258a854 ("ASoC: SOF: Intel: Add Intel specific HDA firmware loader")
Cc: stable at vger.kernel.org # v5.2+
Cc: sound-open-firmware at alsa-project.org
Cc: alsa-devel at alsa-project.org
Cc: linux-kernel at vger.kernel.org
Link: https://lore.kernel.org/lkml/20220224145124.15985-1-ammarfaizi2@gnuweeb.org/ # v1
Link: https://lore.kernel.org/lkml/20220224180850.34592-1-ammarfaizi2@gnuweeb.org/ # v2
Reviewed-by: Peter Ujfalusi <peter.ujfalusi at linux.intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart at linux.intel.com>
Signed-off-by: Ammar Faizi <ammarfaizi2 at gnuweeb.org>
---

On 2/25/22 1:14 AM, Mark Brown wrote:
> On Fri, Feb 25, 2022 at 01:08:50AM +0700, Ammar Faizi wrote:
> 
>> The dmesg says:
>>
>>    [ T1387] sof-audio-pci-intel-tgl 0000:00:1f.3: error: memory alloc failed: -12
>>    [ T1387] BUG: kernel NULL pointer dereference, address: 0000000000000000
>>    [ T1387] #PF: supervisor read access in kernel mode
>>    [ T1387] #PF: error_code(0x0000) - not-present page
>>    [ T1387] PGD 0 P4D 0
>>    [ T1387] Oops: 0000 [#1] PREEMPT SMP NOPTI
> 
> This is still an enormous and not super useful section of backtrace, at
> a glance the backtrace is longer than the rest of the commit :(

Should be okay now...

"cl_stream_prepare()" and "RIP: 0010:dma_free_noncontiguous+0x37/0x80"
should be the important parts to find this bug.

 v3:
   - Address comment from Mark Brown (strip not useful kernel log
     from the commit message, again).

 v2:
   - Append Reviewed-by tag from Peter Ujfalusi.
   - Append Reviewed-by tag from Pierre-Louis Bossart.
   - Address comment from Mark Brown (strip irrelevant kernel log
     from the commit message).

 sound/soc/sof/intel/hda-loader.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/sound/soc/sof/intel/hda-loader.c b/sound/soc/sof/intel/hda-loader.c
index 33306d2023a7..9bbfdab8009d 100644
--- a/sound/soc/sof/intel/hda-loader.c
+++ b/sound/soc/sof/intel/hda-loader.c
@@ -47,7 +47,7 @@ static struct hdac_ext_stream *cl_stream_prepare(struct snd_sof_dev *sdev, unsig
 	ret = snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV_SG, &pci->dev, size, dmab);
 	if (ret < 0) {
 		dev_err(sdev->dev, "error: memory alloc failed: %d\n", ret);
-		goto error;
+		goto out_put;
 	}
 
 	hstream->period_bytes = 0;/* initialize period_bytes */
@@ -58,22 +58,23 @@ static struct hdac_ext_stream *cl_stream_prepare(struct snd_sof_dev *sdev, unsig
 		ret = hda_dsp_iccmax_stream_hw_params(sdev, dsp_stream, dmab, NULL);
 		if (ret < 0) {
 			dev_err(sdev->dev, "error: iccmax stream prepare failed: %d\n", ret);
-			goto error;
+			goto out_free;
 		}
 	} else {
 		ret = hda_dsp_stream_hw_params(sdev, dsp_stream, dmab, NULL);
 		if (ret < 0) {
 			dev_err(sdev->dev, "error: hdac prepare failed: %d\n", ret);
-			goto error;
+			goto out_free;
 		}
 		hda_dsp_stream_spib_config(sdev, dsp_stream, HDA_DSP_SPIB_ENABLE, size);
 	}
 
 	return dsp_stream;
 
-error:
-	hda_dsp_stream_put(sdev, direction, hstream->stream_tag);
+out_free:
 	snd_dma_free_pages(dmab);
+out_put:
+	hda_dsp_stream_put(sdev, direction, hstream->stream_tag);
 	return ERR_PTR(ret);
 }
 

base-commit: 23d04328444a8fa0ca060c5e532220dac8e8bc26
-- 
2.32.0