From mboxrd@z Thu Jan 1 00:00:00 1970 From: akpm@linux-foundation.org Subject: + sys_personality-remove-the-bogus-checks-in-sys_personality-__set_personality-path.patch added to -mm tree Date: Tue, 01 Jun 2010 23:03:10 -0700 Message-ID: <201006020603.o52637nD008191@imap1.linux-foundation.org> Reply-To: linux-kernel@vger.kernel.org Return-path: Received: from smtp1.linux-foundation.org ([140.211.169.13]:35539 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751957Ab0FBGDT (ORCPT ); Wed, 2 Jun 2010 02:03:19 -0400 Sender: mm-commits-owner@vger.kernel.org List-Id: mm-commits@vger.kernel.org To: mm-commits@vger.kernel.org Cc: oleg@redhat.com, hpa@zytor.com, torvalds@linux-foundation.org, wezhang@redhat.com The patch titled sys_personality: remove the bogus checks in sys_personality()->__set_personality() path has been added to the -mm tree. Its filename is sys_personality-remove-the-bogus-checks-in-sys_personality-__set_personality-path.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: sys_personality: remove the bogus checks in sys_personality()->__set_personality() path From: Oleg Nesterov Cleanup, no functional changes. - __set_personality() always changes ->exec_domain/personality, the special case when ->exec_domain remains the same buys nothing but complicates the code. Unify both cases to simplify the code. - The -EINVAL check in sys_personality() was never right. If we assume that set_personality() can fail we should check the value it returns instead of verifying that task->personality was actually changed. Remove it. Before the previous patch it was possible to hit this case due to overflow problems, but this -EINVAL just indicated the kernel bug. OTOH, probably it makes sense to change lookup_exec_domain() to return ERR_PTR() instead of default_exec_domain if the search in exec_domains list fails, and report this error to the user-space. But this means another user-space change, and we have in-kernel users which need fixes. For example, PER_OSF4 falls into PER_MASK for unkown reason and nobody cares to register this domain. Signed-off-by: Oleg Nesterov Cc: Wenming Zhang Cc: Linus Torvalds Cc: "H. Peter Anvin" Signed-off-by: Andrew Morton --- kernel/exec_domain.c | 22 +++++----------------- 1 file changed, 5 insertions(+), 17 deletions(-) diff -puN kernel/exec_domain.c~sys_personality-remove-the-bogus-checks-in-sys_personality-__set_personality-path kernel/exec_domain.c --- a/kernel/exec_domain.c~sys_personality-remove-the-bogus-checks-in-sys_personality-__set_personality-path +++ a/kernel/exec_domain.c @@ -134,23 +134,14 @@ unregister: return 0; } -int -__set_personality(unsigned int personality) +int __set_personality(unsigned int personality) { - struct exec_domain *ep, *oep; - - ep = lookup_exec_domain(personality); - if (ep == current_thread_info()->exec_domain) { - current->personality = personality; - module_put(ep->module); - return 0; - } + struct exec_domain *oep = current_thread_info()->exec_domain; + current_thread_info()->exec_domain = lookup_exec_domain(personality); current->personality = personality; - oep = current_thread_info()->exec_domain; - current_thread_info()->exec_domain = ep; - module_put(oep->module); + return 0; } @@ -192,11 +183,8 @@ SYSCALL_DEFINE1(personality, unsigned in { unsigned int old = current->personality; - if (personality != 0xffffffff) { + if (personality != 0xffffffff) set_personality(personality); - if (current->personality != personality) - return -EINVAL; - } return old; } _ Patches currently in -mm which might be from oleg@redhat.com are sys_personality-change-sys_personality-to-accept-unsigned-int-instead-of-u_long.patch sys_personality-remove-the-bogus-checks-in-sys_personality-__set_personality-path.patch