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kasan/quarantine: fix bugs on qlist_move_cache() 

There are two bugs on qlist_move_cache().  One is that qlist's tail
isn't set properly.  curr->next can be NULL since it is singly linked
list and NULL value on tail is invalid if there is one item on qlist.
Another one is that if cache is matched, qlist_put() is called and it
will set curr->next to NULL.  It would cause to stop the loop
prematurely.

These problems come from complicated implementation so I'd like to
re-implement it completely.  Implementation in this patch is really
simple.  Iterate all qlist_nodes and put them to appropriate list.

Unfortunately, I got this bug sometime ago and lose oops message.  But,
the bug looks trivial and no need to attach oops.

Fixes: 55834c5909 ("mm: kasan: initial memory quarantine implementation")
Link: http://lkml.kernel.org/r/1467766348-22419-1-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Acked-by: Alexander Potapenko <glider@google.com>
Cc: Kuthonuzo Luruo <poll.stdin@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
hifive-unleashed-5.1
Joonsoo Kim 2016-07-14 12:07:17 -07:00 committed by Linus Torvalds
parent 12cb22bb8a
commit 0ab686d8c8
1 changed files with 10 additions and 17 deletions
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27
mm/kasan/quarantine.c
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@ -238,30 +238,23 @@ static void qlist_move_cache(struct qlist_head *from,
struct qlist_head *to,
struct kmem_cache *cache)
{
struct qlist_node *prev = NULL, *curr;
struct qlist_node *curr;
if (unlikely(qlist_empty(from)))
return;
curr = from->head;
qlist_init(from);
while (curr) {
struct qlist_node *qlink = curr;
struct kmem_cache *obj_cache = qlink_to_cache(qlink);
struct qlist_node *next = curr->next;
struct kmem_cache *obj_cache = qlink_to_cache(curr);
if (obj_cache == cache) {
if (unlikely(from->head == qlink)) {
from->head = curr->next;
prev = curr;
} else
prev->next = curr->next;
if (unlikely(from->tail == qlink))
from->tail = curr->next;
from->bytes -= cache->size;
qlist_put(to, qlink, cache->size);
} else {
prev = curr;
}
curr = curr->next;
if (obj_cache == cache)
qlist_put(to, curr, obj_cache->size);
else
qlist_put(from, curr, obj_cache->size);
curr = next;
}
}