From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:47118 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729136AbgCCCuU (ORCPT ); Mon, 2 Mar 2020 21:50:20 -0500 From: Sasha Levin Subject: [PATCH AUTOSEL 4.9 12/13] s390/cio: cio_ignore_proc_seq_next should increase position index Date: Mon, 2 Mar 2020 21:50:01 -0500 Message-Id: <20200303025002.10600-12-sashal@kernel.org> In-Reply-To: <20200303025002.10600-1-sashal@kernel.org> References: <20200303025002.10600-1-sashal@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-s390-owner@vger.kernel.org List-ID: To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Vasily Averin , Cornelia Huck , Christian Borntraeger , Vasily Gorbik , Sasha Levin , linux-s390@vger.kernel.org From: Vasily Averin [ Upstream commit 8b101a5e14f2161869636ff9cb4907b7749dc0c2 ] if seq_file .next fuction does not change position index, read after some lseek can generate unexpected output. Link: https://bugzilla.kernel.org/show_bug.cgi?id=206283 Link: https://lore.kernel.org/r/d44c53a7-9bc1-15c7-6d4a-0c10cb9dffce@virtuozzo.com Reviewed-by: Cornelia Huck Signed-off-by: Christian Borntraeger Signed-off-by: Vasily Averin Signed-off-by: Vasily Gorbik Signed-off-by: Sasha Levin --- drivers/s390/cio/blacklist.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/s390/cio/blacklist.c b/drivers/s390/cio/blacklist.c index 9082476b51db9..4e9f794176d35 100644 --- a/drivers/s390/cio/blacklist.c +++ b/drivers/s390/cio/blacklist.c @@ -302,8 +302,10 @@ static void * cio_ignore_proc_seq_next(struct seq_file *s, void *it, loff_t *offset) { struct ccwdev_iter *iter; + loff_t p = *offset; - if (*offset >= (__MAX_SUBCHANNEL + 1) * (__MAX_SSID + 1)) + (*offset)++; + if (p >= (__MAX_SUBCHANNEL + 1) * (__MAX_SSID + 1)) return NULL; iter = it; if (iter->devno == __MAX_SUBCHANNEL) { @@ -313,7 +315,6 @@ cio_ignore_proc_seq_next(struct seq_file *s, void *it, loff_t *offset) return NULL; } else iter->devno++; - (*offset)++; return iter; } -- 2.20.1