Re: [PATCH] ASoC: SOF: sof-audio: Check snd_sof_widget pointer not NULL
From: AngeloGioacchino Del Regno
Date: Thu Jan 12 2023 - 08:12:37 EST
Il 12/01/23 14:02, Péter Ujfalusi ha scritto:
Hi Angelo,
On 12/01/2023 12:45, AngeloGioacchino Del Regno wrote:
In function sof_unprepare_widgets_in_path(), check if swidget is
actually not NULL, as the widget may not have been initialized at all.
This commit solves the following kernel panic seen on MediaTek MT8195:
[ 18.025215] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000014
[ 18.034266] Mem abort info:
[ 18.037314] ESR = 0x0000000096000004
[ 18.041314] EC = 0x25: DABT (current EL), IL = 32 bits
[ 18.046876] SET = 0, FnV = 0
[ 18.050180] EA = 0, S1PTW = 0
[ 18.053572] FSC = 0x04: level 0 translation fault
[ 18.058700] Data abort info:
[ 18.061832] ISV = 0, ISS = 0x00000004
[ 18.065919] CM = 0, WnR = 0
[ 18.069137] user pgtable: 4k pages, 48-bit VAs, pgdp=0000000115495000
[ 18.075826] [0000000000000014] pgd=0000000000000000, p4d=0000000000000000
[ 18.082867] Internal error: Oops: 0000000096000004 [#1] SMP
[ 18.088688] Modules linked in: af_alg qrtr btusb btrtl btintel btmtk btbcm bluetooth 8021q garp uvcvideo mrp stp ecdh_generic llc ecc videobuf2_vmalloc mt7921e mt7921_common mt76_connac_lib mt76 mac80211 snd_sof_ipc_msg_injector snd_sof_ipc_flood_test cfg80211 snd_sof_mt8195 mtk_adsp_common snd_sof_xtensa_dsp snd_sof_of panfrost rfkill snd_sof crct10dif_ce cros_ec_sensors cros_ec_lid_angle gpu_sched sbs_battery cros_usbpd_logger cros_ec_sensors_core hid_multitouch snd_sof_utils fuse ipv6
[ 18.132109] CPU: 5 PID: 657 Comm: wireplumber Tainted: G W 6.2.0-rc3-next-20230111+ #230
[ 18.141834] Hardware name: Acer Tomato (rev2) board (DT)
[ 18.147392] pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[ 18.154600] pc : sof_unprepare_widgets_in_path.isra.0+0x28/0x10c [snd_sof]
[ 18.161735] lr : sof_walk_widgets_in_order+0x198/0x1d0 [snd_sof]
[ 18.167996] sp : ffff80000eb0b870
[ 18.171558] x29: ffff80000eb0b870 x28: 0000000000000001 x27: ffff5d8e178c4c00
[ 18.178939] x26: ffffbd50140fd758 x25: ffffbd50140fd760 x24: 0000000000000000
[ 18.186321] x23: 0000000000000000 x22: ffff5d8e109dd080 x21: ffff5d8e0a429280
[ 18.193702] x20: 0000000000000000 x19: ffff5d8e11fe4800 x18: 0000000000000000
[ 18.201083] x17: 0000000000000000 x16: ffffbd5073deabb0 x15: 0000000000000000
[ 18.208464] x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000
[ 18.215846] x11: 0000000000000000 x10: 0000000000002780 x9 : ffffbd50140eb4bc
[ 18.223228] x8 : ffff5d8e1b5327e0 x7 : 0000000000000000 x6 : ffff5d8e1b530000
[ 18.230610] x5 : 0000000000000003 x4 : 0000000000000001 x3 : 0000000000000000
[ 18.237991] x2 : 0000000000000000 x1 : ffff5d8e11fe4800 x0 : ffff5d8e0a429280
[ 18.245372] Call trace:
[ 18.248066] sof_unprepare_widgets_in_path.isra.0+0x28/0x10c [snd_sof]
[ 18.254847] sof_walk_widgets_in_order+0x198/0x1d0 [snd_sof]
[ 18.260760] sof_widget_list_free+0x7c/0xbc [snd_sof]
[ 18.266066] sof_pcm_hw_free+0x10c/0x1c0 [snd_sof]
[ 18.271110] snd_soc_pcm_component_hw_free+0x8c/0xe0
[ 18.276327] soc_pcm_hw_clean+0x60/0x11c
[ 18.280498] dpcm_fe_dai_hw_free+0x98/0x110
[ 18.284930] snd_pcm_common_ioctl+0xc48/0x1a2c
[ 18.289624] snd_pcm_ioctl+0x38/0x50
[ 18.293448] __arm64_sys_ioctl+0xb0/0xf4
[ 18.297620] invoke_syscall+0x50/0x120
[ 18.301618] el0_svc_common.constprop.0+0x17c/0x1b0
[ 18.306744] do_el0_svc+0x40/0xc4
[ 18.310307] el0_svc+0x48/0xf0
[ 18.313611] el0t_64_sync_handler+0xb8/0xc0
[ 18.318041] el0t_64_sync+0x1a0/0x1a4
[ 18.321953] Code: aa0103f3 f90013f5 aa0003f5 f9406834 (39405280)
[ 18.328293] ---[ end trace 0000000000000000 ]---
Fixes: 9862dcf70245 ("ASoC: SOF: don't unprepare widget used other pipelines")
Fixes: ce59804d2643 ("ASoC: SOF: clear prepare state when widget is unprepared")
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>
---
sound/soc/sof/sof-audio.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/sound/soc/sof/sof-audio.c b/sound/soc/sof/sof-audio.c
index e1ab8380e7d8..1988717762b3 100644
--- a/sound/soc/sof/sof-audio.c
+++ b/sound/soc/sof/sof-audio.c
@@ -274,7 +274,7 @@ sof_unprepare_widgets_in_path(struct snd_sof_dev *sdev, struct snd_soc_dapm_widg
struct snd_soc_dapm_path *p;
/* return if the widget is in use or if it is already unprepared */
- if (!swidget->prepared || swidget->use_count > 1)
+ if (!swidget || !swidget->prepared || swidget->use_count > 1)
return;
we actually have a pending patch for upstream which did not yet made it
to the gate:
https://github.com/thesofproject/linux/commit/922646d533100044d95a050b222533d59f06020c
It also adds symmetrical check for the prepare path.
Would you be OK if I send that right away to replace your fix?
I didn't know that you had something similar - I've been carrying this patch
locally for ~1.5 months, thinking that it was an issue with MediaTek drivers...
...but after investigating a bit (read: after I've found some time to actually
investigate), it really looked like a more generic issue - for which reason
I decided to send this patch upstream.
Speaking of your patch:
I think that the check that you've added to sof_prepare_widgets_in_path() will
never trigger... at least, it's never been the case here, but that may be a
platform-specific thing (even though I also have virtual widgets on MTK).
Also, your patch misses the Fixes tags (and this fix shall be backported).
Finally, I'd be OK with that if:
1. You add the Fixes tag for backporting; and
2. Describe why the swidget NULL check is required in sof_prepare_widgets_in_path()
and why the legacy HDA machine driver would call that function with NULL swidget
as that looks like a HDA driver bug, rather than a SOF core bug.
Regards,
Angelo