@@ -1079,6 +1079,7 @@ struct topology_update_data {
static int topology_timer_secs = 1;
static int topology_inited;
static int topology_update_needed;
+static struct mutex topology_update_lock;
/*
* Change polling interval for associativity changes.
@@ -1320,6 +1321,11 @@ int numa_update_cpu_topology(bool cpus_locked)
if (!updates)
return 0;
+ if (!mutex_trylock(&topology_update_lock)) {
+ kfree(updates);
+ return 0;
+ }
+
cpumask_clear(&updated_cpus);
for_each_cpu(cpu, &cpu_associativity_changes_mask) {
@@ -1424,6 +1430,7 @@ int numa_update_cpu_topology(bool cpus_locked)
out:
kfree(updates);
topology_update_needed = 0;
+ mutex_unlock(&topology_update_lock);
return changed;
}
@@ -1598,6 +1605,8 @@ static ssize_t topology_write(struct file *file, const char __user *buf,
static int topology_update_init(void)
{
+ mutex_init(&topology_update_lock);
+
/* Do not poll for changes if disabled at boot */
if (topology_updates_enabled)
start_topology_update();
mobility/numa: Ensure that numa_update_cpu_topology() can not be entered multiple times concurrently. It may be accessed through many different paths / concurrent work functions, and the lock ordering may be difficult to ensure otherwise. Signed-off-by: Michael Bringmann <mwb@linux.vnet.ibm.com> --- arch/powerpc/mm/numa.c | 9 +++++++++ 1 file changed, 9 insertions(+)