From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751969AbYJYTrn (ORCPT ); Sat, 25 Oct 2008 15:47:43 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751041AbYJYTre (ORCPT ); Sat, 25 Oct 2008 15:47:34 -0400 Received: from casper.infradead.org ([85.118.1.10]:43061 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750928AbYJYTre convert rfc822-to-8bit (ORCPT ); Sat, 25 Oct 2008 15:47:34 -0400 Date: Sat, 25 Oct 2008 12:47:47 -0700 From: Arjan van de Ven To: torvalds@linux-foundation.com Cc: "Carlos R. Mafra" , Marcin Slusarz , linux-kernel@vger.kernel.org, "Rafael J. Wysocki" , tglx@tglx.de, mingo@elte.hu Subject: [PATCH] select: deal with math overflow from borderline valid userland data Message-ID: <20081025124747.5de4d8e7@infradead.org> Organization: Intel X-Mailer: Claws Mail 3.5.0 (GTK+ 2.12.12; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8BIT X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Linus, please apply this patch, it fixes a regression in 2.6.28-rc1. >>From fdaacc0a980f5d323a21610f7f75b2e92470172e Mon Sep 17 00:00:00 2001 From: Arjan van de Ven Date: Sat, 25 Oct 2008 12:41:41 -0700 Subject: [PATCH] select: deal with math overflow from borderline valid userland data Some userland apps seem to pass in a "0" for the seconds, and several seconds worth of usecs to select(). The old kernels accepted this just fine, so the new kernels must too. However, due to the upscaling of the microseconds to nanoseconds we had some cases where we got math overflow, and depending on the GCC version (due to inlining decisions) that actually resulted in an -EINVAL return. This patch fixes this by adding the excess microseconds to the seconds field. Also with thanks to Marcin Slusarz for spotting some implementation bugs in the diagnostics patches. Reported-by: Carlos R. Mafra Signed-off-by: Arjan van de Ven --- fs/compat.c | 5 +++-- fs/select.c | 5 +++-- 2 files changed, 6 insertions(+), 4 deletions(-) diff --git a/fs/compat.c b/fs/compat.c index fe3c9bf..1510879 100644 --- a/fs/compat.c +++ b/fs/compat.c @@ -1684,8 +1684,9 @@ asmlinkage long compat_sys_select(int n, compat_ulong_t __user *inp, return -EFAULT; to = &end_time; - if (poll_select_set_timeout(to, tv.tv_sec, - tv.tv_usec * NSEC_PER_USEC)) + if (poll_select_set_timeout(to, + tv.tv_sec + (tv.tv_usec / USEC_PER_SEC), + (tv.tv_usec % USEC_PER_SEC) * NSEC_PER_USEC)) return -EINVAL; } diff --git a/fs/select.c b/fs/select.c index 448e440..7fc3124 100644 --- a/fs/select.c +++ b/fs/select.c @@ -519,8 +519,9 @@ asmlinkage long sys_select(int n, fd_set __user *inp, fd_set __user *outp, return -EFAULT; to = &end_time; - if (poll_select_set_timeout(to, tv.tv_sec, - tv.tv_usec * NSEC_PER_USEC)) + if (poll_select_set_timeout(to, + tv.tv_sec + (tv.tv_usec / USEC_PER_SEC), + (tv.tv_usec % USEC_PER_SEC) * NSEC_PER_USEC)) return -EINVAL; } -- 1.5.6.5 -- Arjan van de Ven Intel Open Source Technology Centre For development, discussion and tips for power savings, visit http://www.lesswatts.org