From d7a181da2dfa3190487c446042ba01e07d851c74 Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Wed, 10 Apr 2019 12:49:55 +0200 Subject: ALSA: hda: Fix racy display power access 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 Reviewed-by: Chris Wilson Cc: Imre Deak Signed-off-by: Takashi Iwai --- sound/hda/hdac_component.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'sound/hda/hdac_component.c') diff --git a/sound/hda/hdac_component.c b/sound/hda/hdac_component.c index a6d37b9d6413..6b5caee61c6e 100644 --- a/sound/hda/hdac_component.c +++ b/sound/hda/hdac_component.c @@ -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) { @@ -92,6 +94,8 @@ void snd_hdac_display_power(struct hdac_bus *bus, unsigned int idx, bool enable) bus->display_power_active = false; } } + unlock: + mutex_unlock(&bus->lock); } EXPORT_SYMBOL_GPL(snd_hdac_display_power); -- cgit v1.2.3-59-g8ed1b