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Commit5bd70440cb("ASoC: soc-dai: revert all changes to DAI startup/shutdown sequence"), introduced a slight change of semantics to DAI startup/shutdown. If startup() returns an error, shutdown() is now called for the DAI. This causes a deadlock in hdac_hda which issues a call to snd_hda_codec_pcm_put() in case open fails. Upon error, soc_pcm_open() will call shutdown(), and pcm_put() ends up getting called twice. Result is a deadlock on pcm->open_mutex, as snd_device_free() gets called from within snd_pcm_open(). Typical task backtrace looks like this: [ 334.244627] snd_pcm_dev_disconnect+0x49/0x340 [snd_pcm] [ 334.244634] __snd_device_disconnect.part.0+0x2c/0x50 [snd] [ 334.244640] __snd_device_free+0x7f/0xc0 [snd] [ 334.244650] snd_hda_codec_pcm_put+0x87/0x120 [snd_hda_codec] [ 334.244660] soc_pcm_open+0x6a0/0xbe0 [snd_soc_core] [ 334.244676] ? dpcm_add_paths.isra.0+0x491/0x590 [snd_soc_core] [ 334.244679] ? kfree+0x9a/0x230 [ 334.244686] dpcm_be_dai_startup+0x255/0x300 [snd_soc_core] [ 334.244695] dpcm_fe_dai_open+0x20e/0xf30 [snd_soc_core] [ 334.244701] ? snd_pcm_hw_rule_muldivk+0x110/0x110 [snd_pcm] [ 334.244709] ? dpcm_be_dai_startup+0x300/0x300 [snd_soc_core] [ 334.244714] ? snd_pcm_attach_substream+0x3c4/0x540 [snd_pcm] [ 334.244719] snd_pcm_open_substream+0x69a/0xb60 [snd_pcm] [ 334.244729] ? snd_pcm_release_substream+0x30/0x30 [snd_pcm] [ 334.244732] ? __mutex_lock_slowpath+0x10/0x10 [ 334.244736] snd_pcm_open+0x1b3/0x3c0 [snd_pcm] Fixes:5bd70440cb("ASoC: soc-dai: revert all changes to DAI startup/shutdown sequence") Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com> Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com> Reviewed-by: Rander Wang <rander.wang@linux.intel.com> BugLink: https://github.com/thesofproject/linux/issues/2159 Link: https://lore.kernel.org/r/20200717101950.3885187-3-kai.vehmanen@linux.intel.com Signed-off-by: Mark Brown <broonie@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.