[Intel-gfx] [PATCH] ALSA: hda: fix general protection fault in azx_runtime_idle

[Kai Vehmanen]

Hi,

On Fri, 12 Nov 2021, Takashi Iwai wrote:

> On Thu, 11 Nov 2021 18:39:36 +0100, Kai Vehmanen wrote:
> > And later
> > [   54.770701] Enabling runtime PM for inactive device (0000:00:1f.3) with active children
> > [   54.770718] WARNING: CPU: 0 PID: 10 at drivers/base/power/runtime.c:1439 pm_runtime_enable+0x98/0xb0
> > 
> > Adding a "pm_runtime_set_active(&pci->dev)" to both azx_free() and 
> > azx_probe_continue() seems to help and fix still works.
> 
> Ah yes, I was confused as if it were already called in hdac_device.c,
> but this was about the HD-audio bus controller, not the codec.
> 
> Below is the revised one.
[...]
> Currently we haven't explicitly enable and allow/forbid the runtime PM
> at the probe and the remove phases of HD-audio controller driver, and
> this was the reason of a GPF mentioned in the commit e81478bbe7a1
> ("ALSA: hda: fix general protection fault in azx_runtime_idle");
> namely, even after the resources are released, the runtime PM might be
> still invoked by the bound graphics driver during the remove of the
> controller driver.  Although we've fixed it by clearing the drvdata
> reference, it'd be also better to cover the runtime PM issue more
> properly.
> 
> This patch adds a few more pm_runtime_*() calls at the probe and the
> remove time for setting and cleaning up the runtime PM.  Particularly,
> now more explicitly pm_runtime_enable() and _disable() get called as
> well as pm_runtime_forbid() call at the remove callback, so that a
> use-after-free should be avoided.
> 
> Reported-by: Kai Vehmanen <kai.vehmanen at linux.intel.com>
> Signed-off-by: Takashi Iwai <tiwai at suse.de>

ack, tested this and no warnings anymore.

Reviewed-by: Kai Vehmanen <kai.vehmanen at linux.intel.com>
Tested-by: Kai Vehmanen <kai.vehmanen at linux.intel.com>

Br, Kai