Revision 7d638093d4b0e9ef15bd78f38f11f126e773cc14 authored by Vladimir Davydov on 10 June 2015, 18:14:46 UTC, committed by Linus Torvalds on 10 June 2015, 23:43:43 UTC
When trimming memcg consumption excess (see memory.high), we call
try_to_free_mem_cgroup_pages without checking if we are allowed to sleep
in the current context, which can result in a deadlock. Fix this.
Fixes: 241994ed8649 ("mm: memcontrol: default hierarchy interface for memory")
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 85bd839
dump_stack.c
/*
* Provide a default dump_stack() function for architectures
* which don't implement their own.
*/
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/sched.h>
#include <linux/smp.h>
#include <linux/atomic.h>
static void __dump_stack(void)
{
dump_stack_print_info(KERN_DEFAULT);
show_stack(NULL, NULL);
}
/**
* dump_stack - dump the current task information and its stack trace
*
* Architectures can override this implementation by implementing its own.
*/
#ifdef CONFIG_SMP
static atomic_t dump_lock = ATOMIC_INIT(-1);
asmlinkage __visible void dump_stack(void)
{
int was_locked;
int old;
int cpu;
/*
* Permit this cpu to perform nested stack dumps while serialising
* against other CPUs
*/
preempt_disable();
retry:
cpu = smp_processor_id();
old = atomic_cmpxchg(&dump_lock, -1, cpu);
if (old == -1) {
was_locked = 0;
} else if (old == cpu) {
was_locked = 1;
} else {
cpu_relax();
goto retry;
}
__dump_stack();
if (!was_locked)
atomic_set(&dump_lock, -1);
preempt_enable();
}
#else
asmlinkage __visible void dump_stack(void)
{
__dump_stack();
}
#endif
EXPORT_SYMBOL(dump_stack);
Computing file changes ...
