ALSA: hda: Fix racy display power access (4bdc4209) · Commits · 戴 / test

snd_hdac_display_power() doesn't handle the concurrent calls carefully enough, and it may lead to the doubly get_power or put_power calls, when a runtime PM and an async work get called in racy way. This patch addresses it by reusing the bus->lock mutex that has been used for protecting the link state change in ext bus code, so that it can protect against racy display state changes. The initialization of bus->lock was moved from snd_hdac_ext_bus_init() to snd_hdac_bus_init() as well accordingly. Testcase: igt/i915_pm_rpm/module-reload #glk-dsi Reported-by:

Chris Wilson <chris@chris-wilson.co.uk> Cc: Imre Deak <imre.deak@intel.com> Signed-off-by:

Takashi Iwai <tiwai@suse.de> Reviewed-by:

Chris Wilson <chris@chris-wilson.co.uk> Signed-off-by:

Chris Wilson <chris@chris-wilson.co.uk> Link: https://patchwork.freedesktop.org/patch/msgid/s5h8swiunph.wl-tiwai@suse.de

sound/hda/ext/hdac_ext_bus.c

+0 −1

Original line number	Diff line number	Diff line
		@@ -107,7 +107,6 @@ int snd_hdac_ext_bus_init(struct hdac_bus bus, struct device dev,
		INIT_LIST_HEAD(&bus->hlink_list);
		bus->idx = idx++;

		mutex_init(&bus->lock);
		bus->cmd_dma_state = true;

		return 0;

sound/hda/hdac_bus.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -38,6 +38,7 @@ int snd_hdac_bus_init(struct hdac_bus bus, struct device dev,
		INIT_WORK(&bus->unsol_work, snd_hdac_bus_process_unsol_events);
		spin_lock_init(&bus->reg_lock);
		mutex_init(&bus->cmd_mutex);
		mutex_init(&bus->lock);
		bus->irq = -1;
		return 0;
		}

sound/hda/hdac_component.c

+5 −1

Original line number	Diff line number	Diff line
		@@ -69,13 +69,15 @@ void snd_hdac_display_power(struct hdac_bus *bus, unsigned int idx, bool enable)

		dev_dbg(bus->dev, "display power %s\n",
		enable ? "enable" : "disable");

		mutex_lock(&bus->lock);
		if (enable)
		set_bit(idx, &bus->display_power_status);
		else
		clear_bit(idx, &bus->display_power_status);

		if (!acomp \|\| !acomp->ops)
		return;
		goto unlock;

		if (bus->display_power_status) {
		if (!bus->display_power_active) {
		@@ -98,6 +100,8 @@ void snd_hdac_display_power(struct hdac_bus *bus, unsigned int idx, bool enable)
		bus->display_power_active = 0;
		}
		}
		unlock:
		mutex_unlock(&bus->lock);
		}
		EXPORT_SYMBOL_GPL(snd_hdac_display_power);

Admin message