From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ralf Baechle Subject: Sign extension problem in llseek(2) Date: Tue, 24 Mar 2009 19:24:18 +0100 Message-ID: <20090324182418.GC6509@linux-mips.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from ftp.linux-mips.org ([213.58.128.207]:33844 "EHLO ftp.linux-mips.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757327AbZCXSYf (ORCPT ); Tue, 24 Mar 2009 14:24:35 -0400 Received: from localhost.localdomain ([127.0.0.1]:40639 "EHLO h5.dl5rb.org.uk") by ftp.linux-mips.org with ESMTP id S21368290AbZCXSYY (ORCPT ); Tue, 24 Mar 2009 18:24:24 +0000 Content-Disposition: inline Sender: linux-arch-owner@vger.kernel.org List-ID: To: linux-arch@vger.kernel.org Cc: dann frazier , linux-mips@linux-mips.org In fs/read_write.c: SYSCALL_DEFINE5(llseek, unsigned int, fd, unsigned long, offset_high, unsigned long, offset_low, loff_t __user *, result, unsigned int, origin) ... offset = vfs_llseek(file, ((loff_t) offset_high << 32) | offset_low, origin); On a 64-bit system that define CONFIG_HAVE_SYSCALL_WRAPPERS SYSCALL_DEFINEx will truncate long arguments to 32-bit and on some architectures such as MIPS sign-extended to 64-bit again. On such architectures passing a value with bit 31 in offset_low set will result in a huge 64-bit offset being passed to vfs_llseek() and it failiing with EINVAL. MIPS is affected by this issue. Other 64-bit architectures which also set CONFIG_HAVE_SYSCALL_WRAPPERS and __ARCH_WANT_SYS_LLSEEK are PowerPC, S390 and sparc. The issue was discovered on Debian's MIPS infrastructure machines running e2fsck: [...] This was noticed on one of the Debian infrastructure machines where, after an upgrade, e2fsck began failing with errors like: Error reading block 524290 (Invalid argument) while getting next inode from scan. Ignore error? [...] Ralf