ext4: fix locking typo in mballoc which could cause soft lockup hangs
Smatch (http://repo.or.cz/w/smatch.git/) complains about the locking in
ext4_mb_add_n_trim() from fs/ext4/mballoc.c
4438 list_for_each_entry_rcu(tmp_pa, &lg->lg_prealloc_list[order],
4439 pa_inode_list) {
4440 spin_lock(&tmp_pa->pa_lock);
4441 if (tmp_pa->pa_deleted) {
4442 spin_unlock(&pa->pa_lock);
4443 continue;
4444 }
Brown paper bag time...
Reported-by: Dan Carpenter <error27@gmail.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@kernel.org
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 5f3e3a3..f871677 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -4392,7 +4392,7 @@
pa_inode_list) {
spin_lock(&tmp_pa->pa_lock);
if (tmp_pa->pa_deleted) {
- spin_unlock(&pa->pa_lock);
+ spin_unlock(&tmp_pa->pa_lock);
continue;
}
if (!added && pa->pa_free < tmp_pa->pa_free) {