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From: Takashi Iwai <tiwai@suse.de>
To: Rohit kumar <rohitkr@codeaurora.org>
Cc: plai@codeaurora.org, bgoswami@codeaurora.org,
	lgirdwood@gmail.com, broonie@kernel.org, perex@perex.cz,
	tiwai@suse.com, alsa-devel@alsa-project.org,
	linux-kernel@vger.kernel.org, rohkumar@qti.qualcomm.com,
	srinivas.kandagatla@linaro.org
Subject: Re: [alsa-devel] [PATCH] ASoC: core: Invoke pcm_new() for all DAI-link
Date: Fri, 02 Nov 2018 08:42:10 +0100	[thread overview]
Message-ID: <s5htvl0exil.wl-tiwai@suse.de> (raw)
In-Reply-To: <1541075929-29323-1-git-send-email-rohitkr@codeaurora.org>

On Thu, 01 Nov 2018 13:38:49 +0100,
Rohit kumar wrote:
> 
> Remove no_pcm check to invoke pcm_new() for backend dai-links
> too. This fixes crash in hdmi codec driver during hdmi_codec_startup()
> while accessing chmap_info struct. chmap_info struct memory is
> allocated in pcm_new() of hdmi codec driver which is not invoked
> in case of DPCM when hdmi codec driver is part of backend dai-link.
> 
> Below is the crash stack:
> 
> [   61.635493] Unable to handle kernel NULL pointer dereference at virtual address 00000018
> ..
> [   61.666696]   CM = 0, WnR = 1
> [   61.669778] user pgtable: 4k pages, 39-bit VAs, pgd = ffffffc0d6633000
> [   61.676526] [0000000000000018] *pgd=0000000153fc8003, *pud=0000000153fc8003, *pmd=0000000000000000
> [   61.685793] Internal error: Oops: 96000046 [#1] PREEMPT SMP
> [   61.722955] CPU: 7 PID: 2238 Comm: aplay Not tainted 4.14.72 #21
> ..
> [   61.740269] PC is at hdmi_codec_startup+0x124/0x164
> [   61.745308] LR is at hdmi_codec_startup+0xe4/0x164
> 
> Signed-off-by: Rohit kumar <rohitkr@codeaurora.org>

Did you check whether all drivers have no side-effect by this change?
The hdmi-codec isn't the only driver that has pcm_new ops, so we have
to make sure that such a fundamental change wouldn't bring any
regressions.


thanks,

Takashi

  reply	other threads:[~2018-11-02  7:42 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-01 12:38 Rohit kumar
2018-11-02  7:42 ` Takashi Iwai [this message]
2018-11-02 12:06   ` [alsa-devel] " Rohit Kumar
2018-11-05 11:13     ` Arnaud Pouliquen
2018-11-05 18:14       ` Rohit Kumar
2018-11-06 15:41         ` Arnaud Pouliquen
2018-11-07 16:14           ` Mark Brown
2018-12-13 18:10 ` Applied "ASoC: core: Invoke pcm_new() for all DAI-link" to the asoc tree Mark Brown

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