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=-2.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 8AF5BC6778A for ; Sun, 8 Jul 2018 21:09:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 41E182084C for ; Sun, 8 Jul 2018 21:09:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="MKoG4YPc" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 41E182084C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933464AbeGHVJV (ORCPT ); Sun, 8 Jul 2018 17:09:21 -0400 Received: from mail-pf0-f195.google.com ([209.85.192.195]:37711 "EHLO mail-pf0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933033AbeGHVFf (ORCPT ); Sun, 8 Jul 2018 17:05:35 -0400 Received: by mail-pf0-f195.google.com with SMTP id x10-v6so2291777pfm.4; Sun, 08 Jul 2018 14:05:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=ic95r9CUwqwLACIDyPDH9dFY//qraNC0pvr+AmdEoMM=; b=MKoG4YPcec83UoTKNWCB7U6+jyNhApJzwUJImjNUE6IyzYbfNY/bl7TBwI6jL2/uYF TnWcsoQgw94qVTt7C1x89e0hCObZ8abGzv4F9ovBOjFPHVnPwW6JtMpvZU2CIblTbRAA xjvzaEv/6TNt8VfYjiTJbvMVpE33BOFXY5M+Ojt6qcnu8c9xYc6oZquKimHw43TzjNqP ww49PQ24v57OK2QEZlQezASLxTARZqly4Z8sqCkvbEAUY88H3c/6Z6dQ9et1ICNE75Ge LwYdipx8bvmxn4CDVEUG6YSQFuJDjn8t5RjqUwBHCERb4w0KRmymEKg/M3R8o7ru5G43 //iA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=ic95r9CUwqwLACIDyPDH9dFY//qraNC0pvr+AmdEoMM=; b=lcdM+hKrylEQavoY8MknMhmOnyZH+lgPb15eaBA3Sz1TK6nNvFcEZzoTSNHjQB4ecq Ckz1QXQh5eTphibrbtO37XP3NJpJmQz+HXgn4LQg8A+JtZvGCyVI/5z0zVil44hOWXwn bCptA9hFrMb5BWx6R5sTtl2ovicSWYlzacbCLQubWTy0QpdMnaMHagNO9o3VsK7NS5Ui VrqNzT3CJxB/n/c76AmwL7OYzII1CJIyl3t3T0x8/DNEUDvQEnjqmf7YO16f6GzHBe9c SlXF4rrQd7Jq1slwQFv/aarVrZsirbxgeDpsRWTx2Vrnc3Vbw3/yVJiO7gVpo6hMI6X8 m3VQ== X-Gm-Message-State: APt69E0o5YCT9tl+VT9Sw/pMdQx52ZMXcxpwW4h75mCZmXekPogOVgma bbpet0/nWIexlFr6Xl0A9Zg= X-Google-Smtp-Source: AAOMgpenX6vEr7j4i8RSUR9Lg2ZnAd4QRYSYbamnAwdNbFm672MoJNuvsLuVGWHgMLE0qLD8STGYTA== X-Received: by 2002:a63:383:: with SMTP id 125-v6mr10762509pgd.421.1531083935400; Sun, 08 Jul 2018 14:05:35 -0700 (PDT) Received: from sol.localdomain (c-67-185-97-198.hsd1.wa.comcast.net. [67.185.97.198]) by smtp.gmail.com with ESMTPSA id x68-v6sm23355681pfb.138.2018.07.08.14.05.34 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 08 Jul 2018 14:05:34 -0700 (PDT) From: Eric Biggers To: David Howells , Alexander Viro , linux-fsdevel@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Eric Biggers Subject: [PATCH 03/18] fs_context: fix detecting full log buffer Date: Sun, 8 Jul 2018 14:01:39 -0700 Message-Id: <20180708210154.10423-4-ebiggers3@gmail.com> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20180708210154.10423-1-ebiggers3@gmail.com> References: <20180708210154.10423-1-ebiggers3@gmail.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Eric Biggers When 'head' and 'tail' wrap around, 'log->head - log->tail' will be something like '4 - 252 = -248', and comparing that directly to the array size is wrong. Fix by casting to 'u8'. Fixes: 09aeca629fb3 ("vfs: Implement logging through fs_context") Signed-off-by: Eric Biggers --- fs/fs_context.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/fs/fs_context.c b/fs/fs_context.c index 97e8c1dc4e3b1..a0e22f4c6b64a 100644 --- a/fs/fs_context.c +++ b/fs/fs_context.c @@ -418,7 +418,9 @@ void logfc(struct fs_context *fc, const char *fmt, ...) freeable = 0; store_string: index = log->head & (logsize - 1); - if ((int)log->head - (int)log->tail == 8) { + BUILD_BUG_ON(sizeof(log->head) != sizeof(u8) || + sizeof(log->tail) != sizeof(u8)); + if ((u8)(log->head - log->tail) == logsize) { /* The buffer is full, discard the oldest message */ if (log->need_free & (1 << index)) kfree(log->buffer[index]); -- 2.18.0