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    Subject[PATCH 4.20 316/352] ALSA: hda - Serialize codec registrations
    Date
    4.20-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Takashi Iwai <tiwai@suse.de>

    commit 305a0ade180981686eec1f92aa6252a7c6ebb1cf upstream.

    In the current code, the codec registration may happen both at the
    codec bind time and the end of the controller probe time. In a rare
    occasion, they race with each other, leading to Oops due to the still
    uninitialized card device.

    This patch introduces a simple flag to prevent the codec registration
    at the codec bind time as long as the controller probe is going on.
    The controller probe invokes snd_card_register() that does the whole
    registration task, and we don't need to register each piece
    beforehand.

    Cc: <stable@vger.kernel.org>
    Signed-off-by: Takashi Iwai <tiwai@suse.de>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    include/sound/hda_codec.h | 1 +
    sound/pci/hda/hda_bind.c | 3 ++-
    sound/pci/hda/hda_intel.c | 2 ++
    3 files changed, 5 insertions(+), 1 deletion(-)

    --- a/include/sound/hda_codec.h
    +++ b/include/sound/hda_codec.h
    @@ -68,6 +68,7 @@ struct hda_bus {
    unsigned int response_reset:1; /* controller was reset */
    unsigned int in_reset:1; /* during reset operation */
    unsigned int no_response_fallback:1; /* don't fallback at RIRB error */
    + unsigned int bus_probing :1; /* during probing process */

    int primary_dig_out_type; /* primary digital out PCM type */
    unsigned int mixer_assigned; /* codec addr for mixer name */
    --- a/sound/pci/hda/hda_bind.c
    +++ b/sound/pci/hda/hda_bind.c
    @@ -115,7 +115,8 @@ static int hda_codec_driver_probe(struct
    err = snd_hda_codec_build_controls(codec);
    if (err < 0)
    goto error_module;
    - if (codec->card->registered) {
    + /* only register after the bus probe finished; otherwise it's racy */
    + if (!codec->bus->bus_probing && codec->card->registered) {
    err = snd_card_register(codec->card);
    if (err < 0)
    goto error_module;
    --- a/sound/pci/hda/hda_intel.c
    +++ b/sound/pci/hda/hda_intel.c
    @@ -2228,6 +2228,7 @@ static int azx_probe_continue(struct azx
    int dev = chip->dev_index;
    int err;

    + to_hda_bus(bus)->bus_probing = 1;
    hda->probe_continued = 1;

    /* bind with i915 if needed */
    @@ -2323,6 +2324,7 @@ i915_power_fail:
    if (err < 0)
    hda->init_failed = 1;
    complete_all(&hda->probe_wait);
    + to_hda_bus(bus)->bus_probing = 0;
    return err;
    }


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