From nobody Fri Sep 25 03:17:45 2026 Received: from cstnet.cn (smtp25.cstnet.cn [159.226.251.25]) (using TLSv1.2 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 451CE4B8286; Thu, 17 Sep 2026 09:41:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=159.226.251.25 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789638128; cv=none; b=QQebCTXD4I3h8W52o+X1tXSoe3TKgSfLg29EJSJeCfbJatmwpB9LevLn6+k1uPR746SgpcdximAy08RqxPsbvw37qBcTcW7Df5UbE3DtYCclrBjy8YdeLtULcOH7puZzJYTHuPrZxUj5IjYwcxgWAuRc5xRjal6gIOldWtjNWC0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789638128; c=relaxed/simple; bh=VSjKifo0ugwIi++98rgQVbPk87BELTpT4aewq/eq20A=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=rvJJlvMYgns7bjdP03S6u42tzTiTYsJp0sphEAqLwPA9CWoDIrYv1CvggpIsqfeaqFxYUjZNu37WDFwRzM3Q9/ABL9m/OJPefQ5AB0R2IW6tJ2hTLHCijShhZjdewjosicJrVHR2RObypc5Duit6Rwe6Nvnrv3ZYrr+6jd0DIhk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=iscas.ac.cn; spf=pass smtp.mailfrom=iscas.ac.cn; arc=none smtp.client-ip=159.226.251.25 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=iscas.ac.cn Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=iscas.ac.cn Received: from dfae2b116770.home.arpa (unknown [36.110.52.2]) by APP-05 (Coremail) with SMTP id zQCowACnFUDNtatqg9t9CA--.41301S2; Thu, 17 Sep 2026 17:41:33 +0800 (CST) From: Wentao Liang To: cengku@gmail.com Cc: dm-devel@lists.linux.dev, dongsheng.yang@linux.dev, linux-kernel@vger.kernel.org, mpatocka@redhat.com, Wentao Liang , stable@vger.kernel.org Subject: [PATCH] dm-pcache: Fix use-after-free in kset_replay() Date: Thu, 17 Sep 2026 09:41:33 +0000 Message-Id: <20260917094133.2145340-1-vulab@iscas.ac.cn> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: zQCowACnFUDNtatqg9t9CA--.41301S2 X-Coremail-Antispam: 1UD129KBjvJXoW7Cw1kCFyxAF1kuFy8uF48JFb_yoW8Wr4kpF W3GryYqrW8XrWUCanrJa1jqrySy395AayUW3y7twn3Zw1rury2qFWI9rWjgr1UXFn3GF43 AF1UtF4DuF4jvrJanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUvm1xkIjI8I6I8E6xAIw20EY4v20xvaj40_Wr0E3s1l1IIY67AE w4v_Jr0_Jr4l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0rcxSw2x7M28EF7xvwVC0I7IYx2 IY67AKxVW5JVW7JwA2z4x0Y4vE2Ix0cI8IcVCY1x0267AKxVWxJVW8Jr1l84ACjcxK6I8E 87Iv67AKxVW0oVCq3wA2z4x0Y4vEx4A2jsIEc7CjxVAFwI0_GcCE3s1le2I262IYc4CY6c 8Ij28IcVAaY2xG8wAqx4xG64xvF2IEw4CE5I8CrVC2j2WlYx0E2Ix0cI8IcVAFwI0_JF0_ Jw1lYx0Ex4A2jsIE14v26r4UJVWxJr1lOx8S6xCaFVCjc4AY6r1j6r4UM4x0Y48IcxkI7V AKI48JM4x0x7Aq67IIx4CEVc8vx2IErcIFxwCY1x0262kKe7AKxVWUAVWUtwCF04k20xvY 0x0EwIxGrwCF04k20xvE74AGY7Cv6cx26r48ZrWUJr1UMxC20s026xCaFVCjc4AY6r1j6r 4UMI8I3I0E5I8CrVAFwI0_Jr0_Jr4lx2IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE17CEb7AF 67AKxVWUAVWUtwCIc40Y0x0EwIxGrwCI42IY6xIIjxv20xvE14v26r1j6r1xMIIF0xvE2I x0cI8IcVCY1x0267AKxVW8JVWxJwCI42IY6xAIw20EY4v20xvaj40_Jr0_JF4lIxAIcVC2 z280aVAFwI0_Cr0_Gr1UMIIF0xvEx4A2jsIEc7CjxVAFwI0_GcCE3sUvcSsGvfC2KfnxnU UI43ZEXa7VUbLiSJUUUUU== X-CM-SenderInfo: pyxotu46lvutnvoduhdfq/1tbiBgQNA2qrq3Yt6wAAsW Content-Type: text/plain; charset="utf-8" When the generation of the segment referenced by a replayed key is stale, kset_replay() releases the key with cache_key_put(). The caller holds the only reference, so the key is freed, yet the function then dereferences key->cache_pos to pin the segment. Pin the segment before the key can be released. Fixes: 1d57628ff95b ("dm-pcache: add persistent cache target in device-mapp= er") Cc: stable@vger.kernel.org Signed-off-by: Wentao Liang --- drivers/md/dm-pcache/cache_key.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/md/dm-pcache/cache_key.c b/drivers/md/dm-pcache/cache_= key.c index e068e878231b..668c16a2e111 100644 --- a/drivers/md/dm-pcache/cache_key.c +++ b/drivers/md/dm-pcache/cache_key.c @@ -730,6 +730,12 @@ static int kset_replay(struct pcache_cache *cache, str= uct pcache_cache_kset_onme =20 __set_bit(key->cache_pos.cache_seg->cache_seg_id, cache->seg_map); =20 + /* + * Pin the segment while the key is still alive: the stale key + * below is released and freed by cache_key_put(). + */ + cache_seg_get(key->cache_pos.cache_seg); + /* Check if the segment generation is valid for insertion. */ if (key->seg_gen < key->cache_pos.cache_seg->gen) { cache_key_put(key); @@ -739,8 +745,6 @@ static int kset_replay(struct pcache_cache *cache, stru= ct pcache_cache_kset_onme cache_key_insert(&cache->req_key_tree, key, true); spin_unlock(&cache_subtree->tree_lock); } - - cache_seg_get(key->cache_pos.cache_seg); } =20 return 0; --=20 2.34.1