Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932486Ab0GAUt2 (ORCPT ); Thu, 1 Jul 2010 16:49:28 -0400 Received: from kroah.org ([198.145.64.141]:47104 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932271Ab0GAUt0 (ORCPT ); Thu, 1 Jul 2010 16:49:26 -0400 X-Mailbox-Line: From gregkh@clark.site Thu Jul 1 10:34:27 2010 Message-Id: <20100701173427.462712345@clark.site> User-Agent: quilt/0.48-10.1 Date: Thu, 01 Jul 2010 10:33:13 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, KOSAKI Motohiro , Rusty Russell , Arnd Bergmann , Andi Kleen Subject: [patch 007/164] cpumask: fix compat getaffinity In-Reply-To: <20100701175152.GA2135@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3061 Lines: 96 2.6.33-stable review patch. If anyone has any objections, please let me know. ------------------ From: KOSAKI Motohiro commit fa9dc265ace9774e62f0e31108e5f47911124bda upstream. Commit a45185d2d "cpumask: convert kernel/compat.c" broke libnuma, which abuses sched_getaffinity to find out NR_CPUS in order to parse /sys/devices/system/node/node*/cpumap. On NUMA systems with less than 32 possibly CPUs, the current compat_sys_sched_getaffinity now returns '4' instead of the actual NR_CPUS/8, which makes libnuma bail out when parsing the cpumap. The libnuma call sched_getaffinity(0, bitmap, 4096) at first. It mean the libnuma expect the return value of sched_getaffinity() is either len argument or NR_CPUS. But it doesn't expect to return nr_cpu_ids. Strictly speaking, userland requirement are 1) Glibc assume the return value mean the lengh of initialized of mask argument. E.g. if sched_getaffinity(1024) return 128, glibc make zero fill rest 896 byte. 2) Libnuma assume the return value can be used to guess NR_CPUS in kernel. It assume len-arg Acked-by: Rusty Russell Acked-by: Arnd Bergmann Reported-by: Ken Werner Cc: Andi Kleen Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- kernel/compat.c | 25 +++++++++++-------------- 1 file changed, 11 insertions(+), 14 deletions(-) --- a/kernel/compat.c +++ b/kernel/compat.c @@ -494,29 +494,26 @@ asmlinkage long compat_sys_sched_getaffi { int ret; cpumask_var_t mask; - unsigned long *k; - unsigned int min_length = cpumask_size(); - if (nr_cpu_ids <= BITS_PER_COMPAT_LONG) - min_length = sizeof(compat_ulong_t); - - if (len < min_length) + if ((len * BITS_PER_BYTE) < nr_cpu_ids) + return -EINVAL; + if (len & (sizeof(compat_ulong_t)-1)) return -EINVAL; if (!alloc_cpumask_var(&mask, GFP_KERNEL)) return -ENOMEM; ret = sched_getaffinity(pid, mask); - if (ret < 0) - goto out; + if (ret == 0) { + size_t retlen = min_t(size_t, len, cpumask_size()); - k = cpumask_bits(mask); - ret = compat_put_bitmap(user_mask_ptr, k, min_length * 8); - if (ret == 0) - ret = min_length; - -out: + if (compat_put_bitmap(user_mask_ptr, cpumask_bits(mask), retlen * 8)) + ret = -EFAULT; + else + ret = retlen; + } free_cpumask_var(mask); + return ret; } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/