From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756652Ab3LENaP (ORCPT ); Thu, 5 Dec 2013 08:30:15 -0500 Received: from mailout2.w1.samsung.com ([210.118.77.12]:59630 "EHLO mailout2.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755863Ab3LENaN (ORCPT ); Thu, 5 Dec 2013 08:30:13 -0500 X-AuditID: cbfec7f5-b7fd16d000007299-ca-52a07fe32d4b Subject: [PATCH 1/2] ARM64: check stack pointer in get_wchan To: Catalin Marinas , Will Deacon , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org From: Konstantin Khlebnikov Date: Thu, 05 Dec 2013 17:30:10 +0400 Message-id: <20131205133010.16410.96824.stgit@buzz> User-Agent: StGit/0.15 MIME-version: 1.0 Content-type: text/plain; charset=utf-8 Content-transfer-encoding: 7bit X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFupkluLIzCtJLcpLzFFi42I5/e/4Fd3H9QuCDBZe47B4v6yH0eLHzl5W i02Pr7FaXN41h83i5ccTLA6sHmvmrWH02Lyk3qNvyypGj8+b5AJYorhsUlJzMstSi/TtErgy pr7+y1hwn7Pi5JkOpgbGr+xdjJwcEgImEv2nzrFA2GISF+6tZ+ti5OIQEljKKDHpTwuU08Ak 0Tm/nxmkSljARuL6wiZmkISIwAxGic93foKNYhMwk9i27zYjiM0ioCpx7e87sLG8AsYS6+89 YAOxRYFWrLl0kgkiLijxY/I9oBoODmYBdYkpU3JBwswC8hKb17xlnsDIOwtJ1SyEqllIqhYw Mq9iFE0tTS4oTkrPNdIrTswtLs1L10vOz93ECAm+rzsYlx6zOsQowMGoxMPrmDI/SIg1say4 MvcQowQHs5IIr3DOgiAh3pTEyqrUovz4otKc1OJDjEwcnFINjNPZdcpTw3b0amhtbHT4/Ox3 rMbn9zVm103ivnnIvPY6s3TJlEIx9fwzfmmT/Ht+TDh2JG1Ke8Ff24kvZWXyBZJCLvz9efS8 PgfL/LsBVpabPH0nvGxLMFNWm/PWnqPr84L2hKMrVxkK/LZzy1Up7/+ppvM4IdLaR/uIWeLr MuOD4ZaT3nRvVWIpzkg01GIuKk4EAFkF7ZQcAgAA Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org get_wchan() is lockless. Task may wakeup at any time and change its own stack, thus each next stack frame may be overwritten and filled with random stuff. Signed-off-by: Konstantin Khlebnikov --- arch/arm64/kernel/process.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index de17c89..0adb8f0 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -308,6 +308,7 @@ struct task_struct *__switch_to(struct task_struct *prev, unsigned long get_wchan(struct task_struct *p) { struct stackframe frame; + unsigned long stack_page; int count = 0; if (!p || p == current || p->state == TASK_RUNNING) return 0; @@ -315,9 +316,11 @@ unsigned long get_wchan(struct task_struct *p) frame.fp = thread_saved_fp(p); frame.sp = thread_saved_sp(p); frame.pc = thread_saved_pc(p); + stack_page = (unsigned long)task_stack_page(p); do { - int ret = unwind_frame(&frame); - if (ret < 0) + if (frame.sp < stack_page || + frame.sp >= stack_page + THREAD_SIZE || + unwind_frame(&frame)) return 0; if (!in_sched_functions(frame.pc)) return frame.pc;