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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2017-02-23 20:36:04 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-02-23 20:36:04 +0300 |
| commit | 15192b029509316af4977d2cd389c1eb11183d13 (patch) | |
| tree | cdbbd91a683348cfdb86752a782d583de61a70c9 /fs/gfs2/glock.c | |
| parent | 28cbc335d272f293c4368abd4ac2e17e36805b79 (diff) | |
| parent | f38e5fb95a1f8feda88531eedc98f69b24748712 (diff) | |
| download | linux-15192b029509316af4977d2cd389c1eb11183d13.tar.xz | |
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
Diffstat (limited to 'fs/gfs2/glock.c')
| -rw-r--r-- | fs/gfs2/glock.c | 5 |
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); } |