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btrfs: convert scrub_recover.refs from atomic_t to refcount_t

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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 <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Elena Reshetova 2017-03-03 10:55:21 +02:00 committed by David Sterba
parent a50299ae7c
commit 6f615018b3
1 changed files with 4 additions and 4 deletions
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8
fs/btrfs/scrub.c
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@ -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 @@ out:
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;