Hi Piotr, On 08/06/2013 05:36 PM, Piotr Sarna wrote: > This patch fixes "mm: zcache: core functions added" patch, > available at https://lkml.org/lkml/2013/7/20/90. > It regards incorrect implementation of zcache_cleancache_flush_fs(). > > Function above should be effective only if cleancache pool referred > by pool_id is valid. This issue is checked by testing whether zpool > points to NULL. > > Unfortunately, if filesystem mount fails, such pool is never created > and fs/super.c calls cleancache_invalidate_fs() function with pool_id > parameter set to -1. This results in assigning zpool with pools[-1], > which causes zpool to be not NULL and thus whole function hangs on > uninitialized read-write lock. > > To prevent that behaviour, pool_id should be checked for being positive > before assigning zpool variable with pools[pool_id]. > > Signed-off-by: Piotr Sarna <p.sarna@xxxxxxxxxxxxxxxxxxx> > Acked-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@xxxxxxxxxxx> > Signed-off-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx> Yes, that's a problem. Thank you very much! I'm so glad you are also interesting in zcache. I'm preparing a update version of zcache which is still under testing currently. > --- > mm/zcache.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/mm/zcache.c b/mm/zcache.c > index a2408e8..7e6d2e7 100644 > --- a/mm/zcache.c > +++ b/mm/zcache.c > @@ -600,8 +600,12 @@ static void zcache_cleancache_flush_fs(int pool_id) > struct zcache_rb_entry *entry = NULL; > struct rb_node *node; > unsigned long flags1, flags2; > - struct zcache_pool *zpool = zcache.pools[pool_id]; > + struct zcache_pool *zpool; > + > + if (pool_id < 0) > + return; > > + zpool = zcache.pools[pool_id]; > if (!zpool) > return; > > -- Regards, -Bob -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>