From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 060D5129EC8; Mon, 18 Dec 2023 13:57:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="DJ2Pu3fL" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7AB95C433C7; Mon, 18 Dec 2023 13:57:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1702907878; bh=10UncFFhK69rKroDb+8MjGXFC0vVUlhZV8ajIaAQ2pU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DJ2Pu3fLQx2xDdUIjflpm7nX2NuSyvA+SUOTsr0iSLLlnmue+spq5PgmOFhpuhFEI Sqm2c54SWsqr0DzvuOBIID0nmt63BQsTWxmBAvmoB2DEMRehsmwZpxlUjPQW7qhcIb eORTuvn3oG4q8virGxWgeaM9HCVvu6L1kpfWzLBY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Baokun Li , Jan Kara , Theodore Tso , stable@kernel.org Subject: [PATCH 6.1 080/106] ext4: prevent the normalized size from exceeding EXT_MAX_BLOCKS Date: Mon, 18 Dec 2023 14:51:34 +0100 Message-ID: <20231218135058.489389353@linuxfoundation.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20231218135055.005497074@linuxfoundation.org> References: <20231218135055.005497074@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Baokun Li commit 2dcf5fde6dffb312a4bfb8ef940cea2d1f402e32 upstream. For files with logical blocks close to EXT_MAX_BLOCKS, the file size predicted in ext4_mb_normalize_request() may exceed EXT_MAX_BLOCKS. This can cause some blocks to be preallocated that will not be used. And after [Fixes], the following issue may be triggered: ========================================================= kernel BUG at fs/ext4/mballoc.c:4653! Internal error: Oops - BUG: 00000000f2000800 [#1] SMP CPU: 1 PID: 2357 Comm: xfs_io 6.7.0-rc2-00195-g0f5cc96c367f Hardware name: linux,dummy-virt (DT) pc : ext4_mb_use_inode_pa+0x148/0x208 lr : ext4_mb_use_inode_pa+0x98/0x208 Call trace: ext4_mb_use_inode_pa+0x148/0x208 ext4_mb_new_inode_pa+0x240/0x4a8 ext4_mb_use_best_found+0x1d4/0x208 ext4_mb_try_best_found+0xc8/0x110 ext4_mb_regular_allocator+0x11c/0xf48 ext4_mb_new_blocks+0x790/0xaa8 ext4_ext_map_blocks+0x7cc/0xd20 ext4_map_blocks+0x170/0x600 ext4_iomap_begin+0x1c0/0x348 ========================================================= Here is a calculation when adjusting ac_b_ex in ext4_mb_new_inode_pa(): ex.fe_logical = orig_goal_end - EXT4_C2B(sbi, ex.fe_len); if (ac->ac_o_ex.fe_logical >= ex.fe_logical) goto adjust_bex; The problem is that when orig_goal_end is subtracted from ac_b_ex.fe_len it is still greater than EXT_MAX_BLOCKS, which causes ex.fe_logical to overflow to a very small value, which ultimately triggers a BUG_ON in ext4_mb_new_inode_pa() because pa->pa_free < len. The last logical block of an actual write request does not exceed EXT_MAX_BLOCKS, so in ext4_mb_normalize_request() also avoids normalizing the last logical block to exceed EXT_MAX_BLOCKS to avoid the above issue. The test case in [Link] can reproduce the above issue with 64k block size. Link: https://patchwork.kernel.org/project/fstests/list/?series=804003 Cc: # 6.4 Fixes: 93cdf49f6eca ("ext4: Fix best extent lstart adjustment logic in ext4_mb_new_inode_pa()") Signed-off-by: Baokun Li Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/20231127063313.3734294-1-libaokun1@huawei.com Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman --- fs/ext4/mballoc.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -4110,6 +4110,10 @@ ext4_mb_normalize_request(struct ext4_al start = max(start, rounddown(ac->ac_o_ex.fe_logical, (ext4_lblk_t)EXT4_BLOCKS_PER_GROUP(ac->ac_sb))); + /* avoid unnecessary preallocation that may trigger assertions */ + if (start + size > EXT_MAX_BLOCKS) + size = EXT_MAX_BLOCKS - start; + /* don't cover already allocated blocks in selected range */ if (ar->pleft && start <= ar->lleft) { size -= ar->lleft + 1 - start;