hdmi-codec oopses the kernel when it is unbound from a successfully bound audio subsystem, and is then rebound:
Unable to handle kernel NULL pointer dereference at virtual address 0000001c pgd = ee3f0000 [0000001c] *pgd=3cc59831 Internal error: Oops: 817 [#1] PREEMPT ARM Modules linked in: ext2 snd_soc_spdif_tx vmeta dove_thermal snd_soc_kirkwood ofpart marvell_cesa m25p80 orion_wdt mtd spi_nor des_generic gpio_ir_recv snd_soc_kirkwood_spdif bmm_dmabuf auth_rpcgss nfsd autofs4 etnaviv thermal_sys hwmon gpu_sched tda9950 CPU: 0 PID: 1005 Comm: bash Not tainted 4.20.0+ #1762 Hardware name: Marvell Dove (Cubox) PC is at hdmi_dai_probe+0x68/0x80 LR is at find_held_lock+0x20/0x94 pc : [<c04c7de0>] lr : [<c0063bf4>] psr: 600f0013 sp : ee15bd28 ip : eebd8b1c fp : c093b488 r10: ee048000 r9 : eebdab18 r8 : ee048600 r7 : 00000001 r6 : 00000000 r5 : 00000000 r4 : ee82c100 r3 : 00000006 r2 : 00000001 r1 : c067e38c r0 : ee82c100 Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none[ 297.318599] Control: 10c5387d Table: 2e3f0019 DAC: 00000051 Process bash (pid: 1005, stack limit = 0xee15a248) ... [<c04c7de0>] (hdmi_dai_probe) from [<c04b7060>] (soc_probe_dai.part.9+0x34/0x70) [<c04b7060>] (soc_probe_dai.part.9) from [<c04b81a8>] (snd_soc_instantiate_card+0x734/0xc9c) [<c04b81a8>] (snd_soc_instantiate_card) from [<c04b8b6c>] (snd_soc_add_component+0x29c/0x378) [<c04b8b6c>] (snd_soc_add_component) from [<c04b8c8c>] (snd_soc_register_component+0x44/0x54) [<c04b8c8c>] (snd_soc_register_component) from [<c04c64b4>] (devm_snd_soc_register_component+0x48/0x84) [<c04c64b4>] (devm_snd_soc_register_component) from [<c04c7be8>] (hdmi_codec_probe+0x150/0x260) [<c04c7be8>] (hdmi_codec_probe) from [<c0373124>] (platform_drv_probe+0x48/0x98)
This happens because hdmi_dai_probe() attempts to access the HDMI codec private data, but this has not been assigned by hdmi_dai_probe() before it calls devm_snd_soc_register_component(). Move the call to dev_set_drvdata() before devm_snd_soc_register_component() to avoid this oops.
Signed-off-by: Russell King rmk+kernel@armlinux.org.uk --- Discovered and patched on 4.20.
sound/soc/codecs/hdmi-codec.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/sound/soc/codecs/hdmi-codec.c b/sound/soc/codecs/hdmi-codec.c index 1c628af373eb..6bec7f36eb4c 100644 --- a/sound/soc/codecs/hdmi-codec.c +++ b/sound/soc/codecs/hdmi-codec.c @@ -799,6 +799,8 @@ static int hdmi_codec_probe(struct platform_device *pdev) if (hcd->spdif) hcp->daidrv[i] = hdmi_spdif_dai;
+ dev_set_drvdata(dev, hcp); + ret = devm_snd_soc_register_component(dev, &hdmi_driver, hcp->daidrv, dai_count); if (ret) { @@ -806,8 +808,6 @@ static int hdmi_codec_probe(struct platform_device *pdev) __func__, ret); return ret; } - - dev_set_drvdata(dev, hcp); return 0; }