Messages in this thread | | | Subject | Re: [PATCH v4] kasan/quarantine: fix bugs on qlist_move_cache() | From | Andrey Ryabinin <> | Date | Mon, 4 Jul 2016 12:49:08 +0300 |
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On 07/04/2016 07:31 AM, js1304@gmail.com wrote: > From: Joonsoo Kim <iamjoonsoo.kim@lge.com> > > 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. > > v4: fix cache size bug s/cache->size/obj_cache->size/ > v3: fix build warning > > Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> > --- > mm/kasan/quarantine.c | 21 +++++++-------------- > 1 file changed, 7 insertions(+), 14 deletions(-) > > diff --git a/mm/kasan/quarantine.c b/mm/kasan/quarantine.c > index 4973505..b2e1827 100644 > --- a/mm/kasan/quarantine.c > +++ b/mm/kasan/quarantine.c > @@ -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); > > - 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;
Nit: Wouldn't be more appropriate to swap 'curr' and 'qlink' variable names? Because now qlink is acts as a "current" pointer.
> + > + if (obj_cache == cache) > + qlist_put(to, qlink, obj_cache->size); > + else > + qlist_put(from, qlink, obj_cache->size); > } > } > >
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