Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933983Ab2HWNMK (ORCPT ); Thu, 23 Aug 2012 09:12:10 -0400 Received: from mailhub.sw.ru ([195.214.232.25]:21792 "EHLO relay.sw.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933161Ab2HWNMA (ORCPT ); Thu, 23 Aug 2012 09:12:00 -0400 From: Glauber Costa To: Cc: Andrew Morton , , Peter Zijlstra , Glauber Costa Subject: [PATCH] fork: fix oops after fork failure Date: Thu, 23 Aug 2012 17:08:46 +0400 Message-Id: <1345727326-18730-1-git-send-email-glommer@parallels.com> X-Mailer: git-send-email 1.7.11.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1538 Lines: 43 When we want to duplicate a new process, dup_task_struct() will undergo a series of allocations. If alloc_thread_info_node() fails, we call free_task_struct() and return. This seems right, but it is not. free_task_struct() will not only free the task struct from the kmem_cache, but will also call arch_release_task_struct(). The problem is that this function is supposed to undo whatever arch-specific work done by arch_dup_task_struct(), that is not yet called at this point. The particular problem I ran accross was that in x86, we will arrive at fpu_free() without having ever allocated it. This code is very ancient, and according to git, it is there since the pre-git era. But forks don't fail that often, so that made it well hidden. Signed-off-by: Glauber Costa Reported-by: Frederic Weisbecker --- kernel/fork.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/fork.c b/kernel/fork.c index 152d023..b397435 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -299,7 +299,7 @@ static struct task_struct *dup_task_struct(struct task_struct *orig) ti = alloc_thread_info_node(tsk, node); if (!ti) { - free_task_struct(tsk); + kmem_cache_free(task_struct_cachep, tsk); return NULL; } -- 1.7.11.4 -- 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/