From 6f615018b35fb5ea1ce49673079fc637a0b6be70 Mon Sep 17 00:00:00 2001 From: Elena Reshetova Date: Fri, 3 Mar 2017 10:55:21 +0200 Subject: [PATCH] btrfs: convert scrub_recover.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 b0251eb1239f..c9406bf302b8 100644 --- a/fs/btrfs/scrub.c +++ b/fs/btrfs/scrub.c @@ -64,7 +64,7 @@ struct scrub_ctx; #define SCRUB_MAX_PAGES_PER_BLOCK 16 /* 64k per node/leaf/sector */ struct scrub_recover { - atomic_t refs; + refcount_t refs; struct btrfs_bio *bbio; u64 map_length; }; @@ -857,12 +857,12 @@ static void scrub_fixup_nodatasum(struct btrfs_work *work) static inline void scrub_get_recover(struct scrub_recover *recover) { - atomic_inc(&recover->refs); + refcount_inc(&recover->refs); } static inline void scrub_put_recover(struct scrub_recover *recover) { - if (atomic_dec_and_test(&recover->refs)) { + if (refcount_dec_and_test(&recover->refs)) { btrfs_put_bbio(recover->bbio); kfree(recover); } @@ -1343,7 +1343,7 @@ static int scrub_setup_recheck_block(struct scrub_block *original_sblock, return -ENOMEM; } - atomic_set(&recover->refs, 1); + refcount_set(&recover->refs, 1); recover->bbio = bbio; recover->map_length = mapped_length; -- GitLab