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btrfs: convert btrfs_raid_bio.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 <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>
hifive-unleashed-5.1
Elena Reshetova 2017-03-03 10:55:26 +02:00 committed by David Sterba
parent 99f4cdb16f
commit dec95574f4
1 changed files with 9 additions and 10 deletions
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19
fs/btrfs/raid56.c
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@ -149,7 +149,7 @@ struct btrfs_raid_bio {
int generic_bio_cnt;
atomic_t refs;
refcount_t refs;
atomic_t stripes_pending;
@ -389,7 +389,7 @@ static void __remove_rbio_from_cache(struct btrfs_raid_bio *rbio)
if (bio_list_empty(&rbio->bio_list)) {
if (!list_empty(&rbio->hash_list)) {
list_del_init(&rbio->hash_list);
atomic_dec(&rbio->refs);
refcount_dec(&rbio->refs);
BUG_ON(!list_empty(&rbio->plug_list));
}
}
@ -480,7 +480,7 @@ static void cache_rbio(struct btrfs_raid_bio *rbio)
/* bump our ref if we were not in the list before */
if (!test_and_set_bit(RBIO_CACHE_BIT, &rbio->flags))
atomic_inc(&rbio->refs);
refcount_inc(&rbio->refs);
if (!list_empty(&rbio->stripe_cache)){
list_move(&rbio->stripe_cache, &table->stripe_cache);
@ -689,7 +689,7 @@ static noinline int lock_stripe_add(struct btrfs_raid_bio *rbio)
test_bit(RBIO_CACHE_BIT, &cur->flags) &&
!test_bit(RBIO_RMW_LOCKED_BIT, &cur->flags)) {
list_del_init(&cur->hash_list);
atomic_dec(&cur->refs);
refcount_dec(&cur->refs);
steal_rbio(cur, rbio);
cache_drop = cur;
@ -738,7 +738,7 @@ static noinline int lock_stripe_add(struct btrfs_raid_bio *rbio)
}
}
lockit:
atomic_inc(&rbio->refs);
refcount_inc(&rbio->refs);
list_add(&rbio->hash_list, &h->hash_list);
out:
spin_unlock_irqrestore(&h->lock, flags);
@ -784,7 +784,7 @@ static noinline void unlock_stripe(struct btrfs_raid_bio *rbio)
}
list_del_init(&rbio->hash_list);
atomic_dec(&rbio->refs);
refcount_dec(&rbio->refs);
/*
* we use the plug list to hold all the rbios
@ -801,7 +801,7 @@ static noinline void unlock_stripe(struct btrfs_raid_bio *rbio)
list_del_init(&rbio->plug_list);
list_add(&next->hash_list, &h->hash_list);
atomic_inc(&next->refs);
refcount_inc(&next->refs);
spin_unlock(&rbio->bio_list_lock);
spin_unlock_irqrestore(&h->lock, flags);
@ -843,8 +843,7 @@ static void __free_raid_bio(struct btrfs_raid_bio *rbio)
{
int i;
WARN_ON(atomic_read(&rbio->refs) < 0);
if (!atomic_dec_and_test(&rbio->refs))
if (!refcount_dec_and_test(&rbio->refs))
return;
WARN_ON(!list_empty(&rbio->stripe_cache));
@ -997,7 +996,7 @@ static struct btrfs_raid_bio *alloc_rbio(struct btrfs_fs_info *fs_info,
rbio->stripe_npages = stripe_npages;
rbio->faila = -1;
rbio->failb = -1;
atomic_set(&rbio->refs, 1);
refcount_set(&rbio->refs, 1);
atomic_set(&rbio->error, 0);
atomic_set(&rbio->stripes_pending, 0);