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authorLinus Torvalds <torvalds@linux-foundation.org>2017-02-23 09:36:04 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2017-02-23 09:36:04 -0800
commit15192b029509316af4977d2cd389c1eb11183d13 (patch)
treecdbbd91a683348cfdb86752a782d583de61a70c9
parent28cbc335d272f293c4368abd4ac2e17e36805b79 (diff)
parentf38e5fb95a1f8feda88531eedc98f69b24748712 (diff)
downloadlinux-15192b029509316af4977d2cd389c1eb11183d13.tar.bz2
Merge tag 'gfs2-4.11.addendum' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2
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
-rw-r--r--fs/gfs2/glock.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index 20a13716a672..ec0848fcca02 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -658,9 +658,11 @@ int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
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)
@@ -728,15 +730,18 @@ again:
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);
}