Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752148AbdCCJH0 (ORCPT ); Fri, 3 Mar 2017 04:07:26 -0500 Received: from mga05.intel.com ([192.55.52.43]:27410 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752118AbdCCJHW (ORCPT ); Fri, 3 Mar 2017 04:07:22 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.35,236,1484035200"; d="scan'208";a="1117935843" From: Elena Reshetova To: linux-kernel@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org, peterz@infradead.org, gregkh@linuxfoundation.org, miklos@szeredi.hu, Elena Reshetova , Hans Liljestrand , Kees Cook , David Windsor Subject: [PATCH 2/3] fs, fuse: convert fuse_req.count from atomic_t to refcount_t Date: Fri, 3 Mar 2017 11:04:04 +0200 Message-Id: <1488531845-23463-3-git-send-email-elena.reshetova@intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1488531845-23463-1-git-send-email-elena.reshetova@intel.com> References: <1488531845-23463-1-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: 2161 Lines: 70 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 --- fs/fuse/dev.c | 10 +++++----- fs/fuse/fuse_i.h | 2 +- 2 files changed, 6 insertions(+), 6 deletions(-) diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c index f117926..3e67205 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -44,7 +44,7 @@ static void fuse_request_init(struct fuse_req *req, struct page **pages, INIT_LIST_HEAD(&req->list); INIT_LIST_HEAD(&req->intr_entry); init_waitqueue_head(&req->waitq); - atomic_set(&req->count, 1); + refcount_set(&req->count, 1); req->pages = pages; req->page_descs = page_descs; req->max_pages = npages; @@ -101,14 +101,14 @@ void fuse_request_free(struct fuse_req *req) void __fuse_get_request(struct fuse_req *req) { - atomic_inc(&req->count); + refcount_inc(&req->count); } /* Must be called with > 1 refcount */ static void __fuse_put_request(struct fuse_req *req) { - BUG_ON(atomic_read(&req->count) < 2); - atomic_dec(&req->count); + BUG_ON(refcount_read(&req->count) < 2); + refcount_dec(&req->count); } static void fuse_req_init_context(struct fuse_req *req) @@ -263,7 +263,7 @@ struct fuse_req *fuse_get_req_nofail_nopages(struct fuse_conn *fc, void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req) { - if (atomic_dec_and_test(&req->count)) { + if (refcount_dec_and_test(&req->count)) { if (test_bit(FR_BACKGROUND, &req->flags)) { /* * We get here in the unlikely case that a background diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h index 1d6d67e..9d43740 100644 --- a/fs/fuse/fuse_i.h +++ b/fs/fuse/fuse_i.h @@ -307,7 +307,7 @@ struct fuse_req { struct list_head intr_entry; /** refcount */ - atomic_t count; + refcount_t count; /** Unique ID for the interrupt request */ u64 intr_unique; -- 2.7.4