Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 896a4f47 authored by Iliyan Malchev's avatar Iliyan Malchev Committed by Venkatesh Yadav Abbarapu
Browse files

PM: wakeup_reasons: fix race condition 



log_possible_wakeup_reason() and stop_logging_wakeup_reasons() can race, as the
latter can be called from process context, and both can run on separate cores.

Change-Id: I306441d0be46dd4fe58c55cdc162f9d61a28c27d
Signed-off-by: default avatarIliyan Malchev <malchev@google.com>
Git-commit: 0654cdc20b7463d948434931477b35a018e76db1
Git-repo: https://android.googlesource.com/kernel/msm


Signed-off-by: default avatarVenkatesh Yadav Abbarapu <vabbar@codeaurora.org>
parent ab2c849f

include/linux/wakeup_reason.h

+8 −2
Original line number Diff line number Diff line
@@ -61,16 +61,22 @@ static inline void start_logging_wakeup_reasons(void) 
{

	extern bool log_wakeups;

	extern struct completion wakeups_completion;

	log_wakeups = true;

	ACCESS_ONCE(log_wakeups) = true;

	init_completion(&wakeups_completion);

}



static inline bool logging_wakeup_reasons(void)

static inline bool logging_wakeup_reasons_nosync(void)

{

	extern bool log_wakeups;

	return ACCESS_ONCE(log_wakeups);

}



static inline bool logging_wakeup_reasons(void)

{

	smp_rmb();

	return logging_wakeup_reasons_nosync();

}



void log_base_wakeup_reason(int irq);



void log_suspend_abort_reason(const char *fmt, ...);

kernel/irq/irqdesc.c

+1 −1
Original line number Diff line number Diff line
@@ -354,7 +354,7 @@ int generic_handle_irq(unsigned int irq) 
	if (!desc)

		return -EINVAL;



	if (unlikely(logging_wakeup_reasons()))

	if (unlikely(logging_wakeup_reasons_nosync()))

		return log_possible_wakeup_reason(irq,

				desc,

				generic_handle_irq_desc);

kernel/power/wakeup_reason.c

+9 −2
Original line number Diff line number Diff line
@@ -293,6 +293,7 @@ static struct attribute_group attr_group = { 
static inline void stop_logging_wakeup_reasons(void)

{

	ACCESS_ONCE(log_wakeups) = false;

	smp_wmb();

}



/*
@@ -330,9 +331,16 @@ void log_base_wakeup_reason(int irq) 
struct wakeup_irq_node *

log_possible_wakeup_reason_start(int irq, struct irq_desc *desc, unsigned depth)

{

	BUG_ON(!irqs_disabled() || !logging_wakeup_reasons());

	BUG_ON(!irqs_disabled());

	BUG_ON((signed)depth < 0);



	/* This function can race with a call to stop_logging_wakeup_reasons()

	 * from a thread context.  If this happens, just exit silently, as we are no

	 * longer interested in logging interrupts.

	 */

	if (!logging_wakeup_reasons())

		return NULL;



	/* If suspend was aborted, the base IRQ nodes are missing, and we stop

	 * logging interrupts immediately.

	 */
@@ -540,7 +548,6 @@ static int wakeup_reason_pm_event(struct notifier_block *notifier, 
		/* log_wakeups should have been cleared by now. */

		if (WARN_ON(logging_wakeup_reasons())) {

			stop_logging_wakeup_reasons();

			mb();

			print_wakeup_sources();

		}

		/* monotonic time since boot */