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 X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 04AA2C4332B for ; Wed, 18 Mar 2020 21:04:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C31C820777 for ; Wed, 18 Mar 2020 21:04:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584565488; bh=V4XcCi4zI+m4Y89ggKKf+m+BzhB6paEjnpHJR1dUQbY=; h=From:To:Cc:Subject:Date:List-ID:From; b=wPfB5jigto+SIs4G4GjLeebTlcQRpfpAwSqInTN/CYM7dBy3LuvAEgaeBXvQ9wPiz GLNSaBQjLTVSVXCAqv7m3dra4jO2UkNN9hk6X3oQJBg8NlMDzD4bYjNpjSU4/tDZVl 0WIVmskoje4z4r8igEUSkO1yKwnV3Sor56Q/VodM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728219AbgCRUzM (ORCPT ); Wed, 18 Mar 2020 16:55:12 -0400 Received: from mail.kernel.org ([198.145.29.99]:55480 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728214AbgCRUzM (ORCPT ); Wed, 18 Mar 2020 16:55:12 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id E25FE208E4; Wed, 18 Mar 2020 20:55:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584564911; bh=V4XcCi4zI+m4Y89ggKKf+m+BzhB6paEjnpHJR1dUQbY=; h=From:To:Cc:Subject:Date:From; b=CZLyyrZdXbnBL0Ra4FUCOyjQjnDP85Yv0Ct8ndGon4Y2wEmDEklb7RZjVR0L6vOsi bwL+NcsUzl/x0eeaXefvxoxPP8ecs37DH35KNx85h3pKWRsqCo/p1DgKi9yIXKOMKS OojtKtS/rB8fRygMUml+rZtpOrf5kHsyVKbAsfDM= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Vasily Averin , Tejun Heo , Sasha Levin , cgroups@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 01/37] cgroup-v1: cgroup_pidlist_next should update position index Date: Wed, 18 Mar 2020 16:54:33 -0400 Message-Id: <20200318205509.17053-1-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Vasily Averin [ Upstream commit db8dd9697238be70a6b4f9d0284cd89f59c0e070 ] if seq_file .next fuction does not change position index, read after some lseek can generate unexpected output. # mount | grep cgroup # dd if=/mnt/cgroup.procs bs=1 # normal output ... 1294 1295 1296 1304 1382 584+0 records in 584+0 records out 584 bytes copied dd: /mnt/cgroup.procs: cannot skip to specified offset 83 <<< generates end of last line 1383 <<< ... and whole last line once again 0+1 records in 0+1 records out 8 bytes copied dd: /mnt/cgroup.procs: cannot skip to specified offset 1386 <<< generates last line anyway 0+1 records in 0+1 records out 5 bytes copied https://bugzilla.kernel.org/show_bug.cgi?id=206283 Signed-off-by: Vasily Averin Signed-off-by: Tejun Heo Signed-off-by: Sasha Levin --- kernel/cgroup/cgroup-v1.c | 1 + 1 file changed, 1 insertion(+) diff --git a/kernel/cgroup/cgroup-v1.c b/kernel/cgroup/cgroup-v1.c index 51063e7a93c28..c9628b9a41d23 100644 --- a/kernel/cgroup/cgroup-v1.c +++ b/kernel/cgroup/cgroup-v1.c @@ -501,6 +501,7 @@ static void *cgroup_pidlist_next(struct seq_file *s, void *v, loff_t *pos) */ p++; if (p >= end) { + (*pos)++; return NULL; } else { *pos = *p; -- 2.20.1