From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2BEE5C35296 for ; Tue, 10 May 2022 14:00:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244416AbiEJOC7 (ORCPT ); Tue, 10 May 2022 10:02:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45308 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244609AbiEJNz7 (ORCPT ); Tue, 10 May 2022 09:55:59 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 93BE83F892; Tue, 10 May 2022 06:38:39 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 27323615E9; Tue, 10 May 2022 13:38:38 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 203F9C385D4; Tue, 10 May 2022 13:38:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1652189917; bh=BLhaYnSDWTmnxGZlLocs5B2+vyy327FfiGc2UyQUzZc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DbYJwSl38SknuIwzYral34U0ruJbuEUtVKS/tcjTMVWfosYplvq6tWCgx4r/VqUu6 JKiasACzNbfT2bT0ADHo4ZkxqpefP7FGcM6I7vciXBeEIeCj74HobDRsQlpV0AithE 6Odpv0llX94nGsClQWT8oQbJBmAJ9KqDcYDSzzO0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, =?UTF-8?q?Jan=20H=C3=B6ppner?= , Stefan Haberland , Jens Axboe Subject: [PATCH 5.17 043/140] s390/dasd: Fix read for ESE with blksize < 4k Date: Tue, 10 May 2022 15:07:13 +0200 Message-Id: <20220510130742.851866478@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220510130741.600270947@linuxfoundation.org> References: <20220510130741.600270947@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Jan Höppner commit cd68c48ea15c85f1577a442dc4c285e112ff1b37 upstream. When reading unformatted tracks on ESE devices, the corresponding memory areas are simply set to zero for each segment. This is done incorrectly for blocksizes < 4096. There are two problems. First, the increment of dst is done using the counter of the loop (off), which is increased by blksize every iteration. This leads to a much bigger increment for dst as actually intended. Second, the increment of dst is done before the memory area is set to 0, skipping a significant amount of bytes of memory. This leads to illegal overwriting of memory and ultimately to a kernel panic. This is not a problem with 4k blocksize because blk_queue_max_segment_size is set to PAGE_SIZE, always resulting in a single iteration for the inner segment loop (bv.bv_len == blksize). The incorrectly used 'off' value to increment dst is 0 and the correct memory area is used. In order to fix this for blksize < 4k, increment dst correctly using the blksize and only do it at the end of the loop. Fixes: 5e2b17e712cf ("s390/dasd: Add dynamic formatting support for ESE volumes") Cc: stable@vger.kernel.org # v5.3+ Signed-off-by: Jan Höppner Reviewed-by: Stefan Haberland Link: https://lore.kernel.org/r/20220505141733.1989450-4-sth@linux.ibm.com Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- drivers/s390/block/dasd_eckd.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) --- a/drivers/s390/block/dasd_eckd.c +++ b/drivers/s390/block/dasd_eckd.c @@ -3285,12 +3285,11 @@ static int dasd_eckd_ese_read(struct das cqr->proc_bytes = blk_count * blksize; return 0; } - if (dst && !skip_block) { - dst += off; + if (dst && !skip_block) memset(dst, 0, blksize); - } else { + else skip_block--; - } + dst += blksize; blk_count++; } }