Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752992AbdF0Lko (ORCPT ); Tue, 27 Jun 2017 07:40:44 -0400 Received: from mga03.intel.com ([134.134.136.65]:14331 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752957AbdF0Lke (ORCPT ); Tue, 27 Jun 2017 07:40:34 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.39,399,1493708400"; d="scan'208";a="872136602" From: Elena Reshetova To: axboe@kernel.dk Cc: james.bottomley@hansenpartnership.com, linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, linux-scsi@vger.kernel.org, linux-btrfs@vger.kernel.org, peterz@infradead.org, gregkh@linuxfoundation.org, keescook@chromium.org, fujita.tomonori@lab.ntt.co.jp, mingo@redhat.com, clm@fb.com, jbacik@fb.com, dsterba@suse.com, Elena Reshetova , Hans Liljestrand , David Windsor Subject: [PATCH 1/5] block: convert bio.__bi_cnt from atomic_t to refcount_t Date: Tue, 27 Jun 2017 14:39:56 +0300 Message-Id: <1498563601-10949-2-git-send-email-elena.reshetova@intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1498563601-10949-1-git-send-email-elena.reshetova@intel.com> References: <1498563601-10949-1-git-send-email-elena.reshetova@intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3096 Lines: 103 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 --- block/bio.c | 6 +++--- fs/btrfs/volumes.c | 2 +- include/linux/bio.h | 4 ++-- include/linux/blk_types.h | 3 ++- 4 files changed, 8 insertions(+), 7 deletions(-) diff --git a/block/bio.c b/block/bio.c index 888e780..80032f3 100644 --- a/block/bio.c +++ b/block/bio.c @@ -276,7 +276,7 @@ void bio_init(struct bio *bio, struct bio_vec *table, { memset(bio, 0, sizeof(*bio)); atomic_set(&bio->__bi_remaining, 1); - atomic_set(&bio->__bi_cnt, 1); + refcount_set(&bio->__bi_cnt, 1); bio->bi_io_vec = table; bio->bi_max_vecs = max_vecs; @@ -551,12 +551,12 @@ void bio_put(struct bio *bio) if (!bio_flagged(bio, BIO_REFFED)) bio_free(bio); else { - BIO_BUG_ON(!atomic_read(&bio->__bi_cnt)); + BIO_BUG_ON(!refcount_read(&bio->__bi_cnt)); /* * last put frees it */ - if (atomic_dec_and_test(&bio->__bi_cnt)) + if (refcount_dec_and_test(&bio->__bi_cnt)) bio_free(bio); } } diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 017b67d..cd8a5d5 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -446,7 +446,7 @@ static noinline void run_scheduled_bios(struct btrfs_device *device) waitqueue_active(&fs_info->async_submit_wait)) wake_up(&fs_info->async_submit_wait); - BUG_ON(atomic_read(&cur->__bi_cnt) == 0); + BUG_ON(refcount_read(&cur->__bi_cnt) == 0); /* * if we're doing the sync list, record that our diff --git a/include/linux/bio.h b/include/linux/bio.h index d1b04b0..bfd0661 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -229,7 +229,7 @@ static inline void bio_get(struct bio *bio) { bio->bi_flags |= (1 << BIO_REFFED); smp_mb__before_atomic(); - atomic_inc(&bio->__bi_cnt); + refcount_inc(&bio->__bi_cnt); } static inline void bio_cnt_set(struct bio *bio, unsigned int count) @@ -238,7 +238,7 @@ static inline void bio_cnt_set(struct bio *bio, unsigned int count) bio->bi_flags |= (1 << BIO_REFFED); smp_mb__before_atomic(); } - atomic_set(&bio->__bi_cnt, count); + refcount_set(&bio->__bi_cnt, count); } static inline bool bio_flagged(struct bio *bio, unsigned int bit) diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h index 61339bc..f6e5daa 100644 --- a/include/linux/blk_types.h +++ b/include/linux/blk_types.h @@ -7,6 +7,7 @@ #include #include +#include struct bio_set; struct bio; @@ -81,7 +82,7 @@ struct bio { unsigned short bi_max_vecs; /* max bvl_vecs we can hold */ - atomic_t __bi_cnt; /* pin count */ + refcount_t __bi_cnt; /* pin count */ struct bio_vec *bi_io_vec; /* the actual vec list */ -- 2.7.4