From f5886c7f96f2542382d3a983c5f13e03d7fc5259 Mon Sep 17 00:00:00 2001
From: Catalin Marinas <catalin.marinas@arm.com>
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 <catalin.marinas@arm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
mm/kmemleak.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index 5aabd41ffb8faf..487267310a8447 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);
--
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