From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932252AbWDUEsE (ORCPT ); Fri, 21 Apr 2006 00:48:04 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932253AbWDUEog (ORCPT ); Fri, 21 Apr 2006 00:44:36 -0400 Received: from mail.kroah.org ([69.55.234.183]:14210 "EHLO perch.kroah.org") by vger.kernel.org with ESMTP id S932252AbWDUEoS (ORCPT ); Fri, 21 Apr 2006 00:44:18 -0400 Date: Thu, 20 Apr 2006 21:39:45 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: Justin Forbes , Zwane Mwaikambo , "Theodore Ts'o" , Randy Dunlap , Dave Jones , Chuck Wolber , torvalds@osdl.org, akpm@osdl.org, alan@lxorguk.ukuu.org.uk, Greg Kroah-Hartman Subject: [patch 14/22] x86: be careful about tailcall breakage for sys_opentoo Message-ID: <20060421043945.GS12846@kroah.com> References: <20060421043353.602539000@blue.kroah.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline; filename="x86-be-careful-about-tailcall-breakage-for-sys_open-too.patch" In-Reply-To: <20060421043706.GA12846@kroah.com> User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org From: Linus Torvalds x86: be careful about tailcall breakage for sys_open[at] too Came up through a quick grep for other cases similar to the ftruncate() one in commit 0a489cb3b6a7b277030cdbc97c2c65905db94536. Also, add a comment, so that people who read the code understand why we do what looks like a no-op. (Again, this won't actually matter to any sane user, since libc will save and restore the register gcc stomps on, but it's still wrong to stomp on it) Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- fs/open.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) --- linux-2.6.16.9.orig/fs/open.c +++ linux-2.6.16.9/fs/open.c @@ -331,6 +331,7 @@ out: asmlinkage long sys_ftruncate(unsigned int fd, unsigned long length) { long ret = do_sys_ftruncate(fd, length, 1); + /* avoid REGPARM breakage on x86: */ prevent_tail_call(ret); return ret; } @@ -345,6 +346,7 @@ asmlinkage long sys_truncate64(const cha asmlinkage long sys_ftruncate64(unsigned int fd, loff_t length) { long ret = do_sys_ftruncate(fd, length, 0); + /* avoid REGPARM breakage on x86: */ prevent_tail_call(ret); return ret; } @@ -1087,20 +1089,30 @@ long do_sys_open(int dfd, const char __u asmlinkage long sys_open(const char __user *filename, int flags, int mode) { + long ret; + if (force_o_largefile()) flags |= O_LARGEFILE; - return do_sys_open(AT_FDCWD, filename, flags, mode); + ret = do_sys_open(AT_FDCWD, filename, flags, mode); + /* avoid REGPARM breakage on x86: */ + prevent_tail_call(ret); + return ret; } EXPORT_SYMBOL_GPL(sys_open); asmlinkage long sys_openat(int dfd, const char __user *filename, int flags, int mode) { + long ret; + if (force_o_largefile()) flags |= O_LARGEFILE; - return do_sys_open(dfd, filename, flags, mode); + ret = do_sys_open(dfd, filename, flags, mode); + /* avoid REGPARM breakage on x86: */ + prevent_tail_call(ret); + return ret; } EXPORT_SYMBOL_GPL(sys_openat); --