markers: don't risk NULL deref in marker
get_marker() may return NULL, so test for it.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/kernel/marker.c b/kernel/marker.c
index 50effc0..48a4ea5a 100644
--- a/kernel/marker.c
+++ b/kernel/marker.c
@@ -698,14 +698,12 @@
{
struct marker_entry *entry;
struct marker_probe_closure *old;
- int ret = 0;
+ int ret = -ENOENT;
mutex_lock(&markers_mutex);
entry = get_marker(name);
- if (!entry) {
- ret = -ENOENT;
+ if (!entry)
goto end;
- }
if (entry->rcu_pending)
rcu_barrier();
old = marker_entry_remove_probe(entry, probe, probe_private);
@@ -713,12 +711,15 @@
marker_update_probes(); /* may update entry */
mutex_lock(&markers_mutex);
entry = get_marker(name);
+ if (!entry)
+ goto end;
entry->oldptr = old;
entry->rcu_pending = 1;
/* write rcu_pending before calling the RCU callback */
smp_wmb();
call_rcu(&entry->rcu, free_old_closure);
remove_marker(name); /* Ignore busy error message */
+ ret = 0;
end:
mutex_unlock(&markers_mutex);
return ret;