From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 53736299920; Sat, 12 Sep 2026 09:37:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789205823; cv=none; b=ATlYOtxUBSgOaOWIPKSjHQCetIcWA9S3WU9UtRPbryJ0uygX39rgiBbpqK1UPMAzlFgaQRJVr41sNvd6g6k2j+PJmgMb4YYkEl+yAWPq4JYvvHon9iEuRextVA/o2oZJO+68fGYGuYm9Foh9tAIH7zWsRh9/u7PIuF8PFAtYmNY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789205823; c=relaxed/simple; bh=H3q5jjqgKY5n7RjqRJvjGFfjdo+B1lYfw95r3KiJw+A=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=EEJ2cxZ37/cU5z+keN1Srg73t7pTxYBarR9udeTWJIRZjYHeo1KcUHemi0m7CdpJyGXR7FYXVAUwqoRO3Vi9vrOAeDSpOMqshR4YBo1k/AmSeK8EY3gnkrGGWVnKwhWRC4pNEyJzeg8KhNqvDMiPFeBd/CXmAdwotORtsGEondQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=hFjhi4ZV; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="hFjhi4ZV" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E8E041F000FF; Sat, 12 Sep 2026 09:37:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789205822; bh=SYO0iRY5m084Crjx7fxvmD1KUlYx+JVHpi5Pp9eorJU=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=hFjhi4ZVs7DQhPE20FEy3GegOSVWWW6DaTd8TNB6ucVwIU3OcfEIp9JGHJQ0MGTKm l7ckqzGOW9asc+YOAwAtYfoOVRUd9ut5xXG8DqLvvQ/VX8PRkWLW1lu1P8J4iU9CQv kQwkCVEElRhe2cf2D/poDNywm1dRHr6BzL2nEdDc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Bryam Vargas , Mikulas Patocka , Sasha Levin Subject: [PATCH 6.18 0079/1518] dm-pcache: reject a kset that overruns its segment Date: Sat, 12 Sep 2026 08:37:28 +0200 Message-ID: <20260912065625.244295028@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260912065623.398859879@linuxfoundation.org> References: <20260912065623.398859879@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Bryam Vargas [ Upstream commit 7ac1f10f987a2ffae4aecf0e2ceca8f552b665cb ] cache_replay(), the writeback worker and the GC worker read a kset of get_kset_onmedia_size() bytes and advance the position by it. A forged key_num makes that size exceed the segment's remaining space, so the advance walks past the segment and trips the cache_pos_advance() BUG_ON. Reject a kset whose on-media size exceeds cache_seg_remain() before use. Fixes: 1d57628ff95b ("dm-pcache: add persistent cache target in device-mapper") Cc: stable@vger.kernel.org Signed-off-by: Bryam Vargas Signed-off-by: Mikulas Patocka [ backported missing writeback_errors support from the upstream dependency. ] Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/md/dm-pcache/cache.h | 1 + drivers/md/dm-pcache/cache_gc.c | 5 +++++ drivers/md/dm-pcache/cache_key.c | 5 +++++ drivers/md/dm-pcache/cache_writeback.c | 8 ++++++++ 4 files changed, 19 insertions(+) --- a/drivers/md/dm-pcache/cache.h +++ b/drivers/md/dm-pcache/cache.h @@ -180,6 +180,7 @@ struct pcache_cache { u32 advance; int ret; } writeback_ctx; + atomic_t writeback_errors; char gc_kset_onmedia_buf[PCACHE_KSET_ONMEDIA_SIZE_MAX]; struct delayed_work gc_work; --- a/drivers/md/dm-pcache/cache_gc.c +++ b/drivers/md/dm-pcache/cache_gc.c @@ -134,6 +134,11 @@ void pcache_cache_gc_fn(struct work_stru continue; } + if (get_kset_onmedia_size(kset_onmedia) > cache_seg_remain(&key_tail)) { + atomic_inc(&cache->gc_errors); + return; + } + for (i = 0; i < kset_onmedia->key_num; i++) { struct pcache_cache_key key_tmp = { 0 }; --- a/drivers/md/dm-pcache/cache_key.c +++ b/drivers/md/dm-pcache/cache_key.c @@ -811,6 +811,11 @@ int cache_replay(struct pcache_cache *ca } /* Replay the kset and check for errors. */ + if (get_kset_onmedia_size(kset_onmedia) > cache_seg_remain(pos)) { + ret = -EIO; + goto out; + } + ret = kset_replay(cache, kset_onmedia); if (ret) goto out; --- a/drivers/md/dm-pcache/cache_writeback.c +++ b/drivers/md/dm-pcache/cache_writeback.c @@ -229,6 +229,9 @@ void cache_writeback_fn(struct work_stru if (pcache_is_stopping(pcache)) goto unlock; + if (atomic_read(&cache->writeback_errors)) + goto unlock; + kset_onmedia = (struct pcache_cache_kset_onmedia *)cache->wb_kset_onmedia_buf; mutex_lock(&cache->dirty_tail_lock); @@ -246,6 +249,11 @@ void cache_writeback_fn(struct work_stru goto queue_work; } + if (get_kset_onmedia_size(kset_onmedia) > cache_seg_remain(&dirty_tail)) { + atomic_inc(&cache->writeback_errors); + goto unlock; + } + ret = cache_kset_insert_tree(cache, kset_onmedia); if (ret) { delay = PCACHE_CACHE_WRITEBACK_INTERVAL;