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

Commit ab992dc3 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Linus Torvalds
Browse files

watchdog: Fix merge 'conflict' 



Two watchdog changes that came through different trees had a non
conflicting conflict, that is, one changed the semantics of a variable
but no actual code conflict happened. So the merge appeared fine, but
the resulting code did not behave as expected.

Commit 195daf66 ("watchdog: enable the new user interface of the
watchdog mechanism") changes the semantics of watchdog_user_enabled,
which thereafter is only used by the functions introduced by
b3738d29 ("watchdog: Add watchdog enable/disable all functions").

There further appears to be a distinct lack of serialization between
setting and using watchdog_enabled, so perhaps we should wrap the
{en,dis}able_all() things in watchdog_proc_mutex.

This patch fixes a s2r failure reported by Michal; which I cannot
readily explain. But this does make the code internally consistent
again.

Reported-and-tested-by: default avatarMichal Hocko <mhocko@suse.cz>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 7cf7d424

kernel/watchdog.c

+15 −5
Original line number Original line Diff line number Diff line
@@ -41,6 +41,8 @@ 
#define NMI_WATCHDOG_ENABLED      (1 << NMI_WATCHDOG_ENABLED_BIT)

#define NMI_WATCHDOG_ENABLED      (1 << NMI_WATCHDOG_ENABLED_BIT)

#define SOFT_WATCHDOG_ENABLED     (1 << SOFT_WATCHDOG_ENABLED_BIT)

#define SOFT_WATCHDOG_ENABLED     (1 << SOFT_WATCHDOG_ENABLED_BIT)





static DEFINE_MUTEX(watchdog_proc_mutex);



#ifdef CONFIG_HARDLOCKUP_DETECTOR

#ifdef CONFIG_HARDLOCKUP_DETECTOR

static unsigned long __read_mostly watchdog_enabled = SOFT_WATCHDOG_ENABLED|NMI_WATCHDOG_ENABLED;

static unsigned long __read_mostly watchdog_enabled = SOFT_WATCHDOG_ENABLED|NMI_WATCHDOG_ENABLED;

#else

#else
@@ -608,26 +610,36 @@ void watchdog_nmi_enable_all(void) 
{

{

	int cpu;

	int cpu;





	if (!watchdog_user_enabled)

	mutex_lock(&watchdog_proc_mutex);

		return;



	if (!(watchdog_enabled & NMI_WATCHDOG_ENABLED))

		goto unlock;





	get_online_cpus();

	get_online_cpus();

	for_each_online_cpu(cpu)

	for_each_online_cpu(cpu)

		watchdog_nmi_enable(cpu);

		watchdog_nmi_enable(cpu);

	put_online_cpus();

	put_online_cpus();



unlock:

	mutex_lock(&watchdog_proc_mutex);

}

}





void watchdog_nmi_disable_all(void)

void watchdog_nmi_disable_all(void)

{

{

	int cpu;

	int cpu;





	mutex_lock(&watchdog_proc_mutex);



	if (!watchdog_running)

	if (!watchdog_running)

		return;

		goto unlock;





	get_online_cpus();

	get_online_cpus();

	for_each_online_cpu(cpu)

	for_each_online_cpu(cpu)

		watchdog_nmi_disable(cpu);

		watchdog_nmi_disable(cpu);

	put_online_cpus();

	put_online_cpus();



unlock:

	mutex_unlock(&watchdog_proc_mutex);

}

}

#else

#else

static int watchdog_nmi_enable(unsigned int cpu) { return 0; }

static int watchdog_nmi_enable(unsigned int cpu) { return 0; }
@@ -744,8 +756,6 @@ static int proc_watchdog_update(void) 




}

}





static DEFINE_MUTEX(watchdog_proc_mutex);



/*

/*

 * common function for watchdog, nmi_watchdog and soft_watchdog parameter

 * common function for watchdog, nmi_watchdog and soft_watchdog parameter

 *

 *