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authorTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>2014-01-02 19:52:20 +0900
committerSteven Whitehouse <swhiteho@redhat.com>2014-01-02 12:18:04 +0000
commit0b3a2c9968d453d5827e635a6f3d69129f70af66 (patch)
treeb5c0d6cee7f88e7d6dfc99afc51ec2be066906a8
parent582d2f7aedfde9e1a01170deb003df510aa778d3 (diff)
GFS2: Fix unsafe dereference in dump_holder()
GLOCK_BUG_ON() might call this function without RCU read lock. Make sure that RCU read lock is held when using task_struct returned from pid_task(). Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
-rw-r--r--fs/gfs2/glock.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index c8420f7e4db..6f7a47c0525 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -1655,6 +1655,7 @@ static int dump_holder(struct seq_file *seq, const struct gfs2_holder *gh)
struct task_struct *gh_owner = NULL;
char flags_buf[32];
+ rcu_read_lock();
if (gh->gh_owner_pid)
gh_owner = pid_task(gh->gh_owner_pid, PIDTYPE_PID);
gfs2_print_dbg(seq, " H: s:%s f:%s e:%d p:%ld [%s] %pS\n",
@@ -1664,6 +1665,7 @@ static int dump_holder(struct seq_file *seq, const struct gfs2_holder *gh)
gh->gh_owner_pid ? (long)pid_nr(gh->gh_owner_pid) : -1,
gh_owner ? gh_owner->comm : "(ended)",
(void *)gh->gh_ip);
+ rcu_read_unlock();
return 0;
}