From f5886c7f96f2542382d3a983c5f13e03d7fc5259 Mon Sep 17 00:00:00 2001 From: Catalin Marinas Date: Wed, 29 Jul 2009 16:26:57 +0100 Subject: [PATCH] kmemleak: Protect the seq start/next/stop sequence by rcu_read_lock() Objects passed to kmemleak_seq_next() have an incremented reference count (hence not freed) but they may point via object_list.next to other freed objects. To avoid this, the whole start/next/stop sequence must be protected by rcu_read_lock(). Signed-off-by: Catalin Marinas Signed-off-by: Linus Torvalds --- mm/kmemleak.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/mm/kmemleak.c b/mm/kmemleak.c index 5aabd41ffb8f..487267310a84 100644 --- a/mm/kmemleak.c +++ b/mm/kmemleak.c @@ -1217,7 +1217,6 @@ static void *kmemleak_seq_start(struct seq_file *seq, loff_t *pos) } object = NULL; out: - rcu_read_unlock(); return object; } @@ -1233,13 +1232,11 @@ static void *kmemleak_seq_next(struct seq_file *seq, void *v, loff_t *pos) ++(*pos); - rcu_read_lock(); list_for_each_continue_rcu(n, &object_list) { next_obj = list_entry(n, struct kmemleak_object, object_list); if (get_object(next_obj)) break; } - rcu_read_unlock(); put_object(prev_obj); return next_obj; @@ -1255,6 +1252,7 @@ static void kmemleak_seq_stop(struct seq_file *seq, void *v) * kmemleak_seq_start may return ERR_PTR if the scan_mutex * waiting was interrupted, so only release it if !IS_ERR. */ + rcu_read_unlock(); mutex_unlock(&scan_mutex); if (v) put_object(v); -- 2.30.2