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Commit 6f615018 authored by Elena Reshetova's avatar Elena Reshetova Committed by David Sterba
Browse files

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: default avatarElena Reshetova <elena.reshetova@intel.com>
Signed-off-by: default avatarHans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarDavid Windsor <dwindsor@gmail.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent a50299ae

fs/btrfs/scrub.c

+4 −4
Original line number Diff line number Diff line
@@ -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;