Pull GFS2 fix from Bob Peterson:
"This is an addendum for the 4.11 merge window.
Andy Price wrote this patch to close a nasty race condition that
allows access to glocks that are being destroyed. Without this patch,
GFS2 is vulnerable to random corruption and kernel panic"
* tag 'gfs2-4.11.addendum' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2:
gfs2: Add missing rcu locking for glock lookup
struct kmem_cache *cachep;
int ret, tries = 0;
+ rcu_read_lock();
gl = rhashtable_lookup_fast(&gl_hash_table, &name, ht_parms);
if (gl && !lockref_get_not_dead(&gl->gl_lockref))
gl = NULL;
+ rcu_read_unlock();
*glp = gl;
if (gl)
if (ret == -EEXIST) {
ret = 0;
+ rcu_read_lock();
tmp = rhashtable_lookup_fast(&gl_hash_table, &name, ht_parms);
if (tmp == NULL || !lockref_get_not_dead(&tmp->gl_lockref)) {
if (++tries < 100) {
+ rcu_read_unlock();
cond_resched();
goto again;
}
tmp = NULL;
ret = -ENOMEM;
}
+ rcu_read_unlock();
} else {
WARN_ON_ONCE(ret);
}