From 78a764504d1e11411bec0e068c5d9e0a417aff08 Mon Sep 17 00:00:00 2001 From: Elena Reshetova Date: Fri, 3 Mar 2017 10:55:24 +0200 Subject: [PATCH] btrfs: convert scrub_parity.refs from atomic_t to refcount_t refcount_t type and corresponding API should be used instead of atomic_t when the variable is used as a reference counter. This allows to avoid accidental refcounter overflows that might lead to use-after-free situations. Signed-off-by: Elena Reshetova Signed-off-by: Hans Liljestrand Signed-off-by: Kees Cook Signed-off-by: David Windsor Signed-off-by: David Sterba --- fs/btrfs/scrub.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c index d2c35848e61d..8130ab11821f 100644 --- a/fs/btrfs/scrub.c +++ b/fs/btrfs/scrub.c @@ -142,7 +142,7 @@ struct scrub_parity { int stripe_len; - atomic_t refs; + refcount_t refs; struct list_head spages; @@ -2822,12 +2822,12 @@ static inline int scrub_calc_parity_bitmap_len(int nsectors) static void scrub_parity_get(struct scrub_parity *sparity) { - atomic_inc(&sparity->refs); + refcount_inc(&sparity->refs); } static void scrub_parity_put(struct scrub_parity *sparity) { - if (!atomic_dec_and_test(&sparity->refs)) + if (!refcount_dec_and_test(&sparity->refs)) return; scrub_parity_check_and_repair(sparity); @@ -2879,7 +2879,7 @@ static noinline_for_stack int scrub_raid56_parity(struct scrub_ctx *sctx, sparity->scrub_dev = sdev; sparity->logic_start = logic_start; sparity->logic_end = logic_end; - atomic_set(&sparity->refs, 1); + refcount_set(&sparity->refs, 1); INIT_LIST_HEAD(&sparity->spages); sparity->dbitmap = sparity->bitmap; sparity->ebitmap = (void *)sparity->bitmap + bitmap_len; -- 2.39.5