From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965015AbcHDWYm (ORCPT ); Thu, 4 Aug 2016 18:24:42 -0400 Received: from mx1.redhat.com ([209.132.183.28]:59738 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933899AbcHDWYF (ORCPT ); Thu, 4 Aug 2016 18:24:05 -0400 From: Josh Poimboeuf To: Thomas Gleixner , Ingo Molnar , "H . Peter Anvin" Cc: x86@kernel.org, linux-kernel@vger.kernel.org, Andy Lutomirski , Linus Torvalds , Steven Rostedt , Brian Gerst , Kees Cook , Peter Zijlstra , Frederic Weisbecker , Byungchul Park Subject: [PATCH v2 43/44] x86/unwind: warn on bad stack return address Date: Thu, 4 Aug 2016 17:22:39 -0500 Message-Id: <3eb6b7e36d5e82bd03b9d58b0864846694b2daac.1470345772.git.jpoimboe@redhat.com> In-Reply-To: References: X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Thu, 04 Aug 2016 22:24:00 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If __kernel_text_address() doesn't recognize a return address on the stack, it probably means that it's some generated code which __kernel_text_address() doesn't know about yet. Otherwise there's probably some stack corruption. Either way, warn about it. Use printk_deferred_once() because the unwinder can be called with the console lock by lockdep via save_stack_trace(). Signed-off-by: Josh Poimboeuf --- arch/x86/kernel/unwind_frame.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/unwind_frame.c b/arch/x86/kernel/unwind_frame.c index d90c2c9..f943413 100644 --- a/arch/x86/kernel/unwind_frame.c +++ b/arch/x86/kernel/unwind_frame.c @@ -17,7 +17,13 @@ unsigned long unwind_get_return_address(struct unwind_state *state) addr = ftrace_graph_ret_addr(state->task, &state->graph_idx, *addr_p, addr_p); - return __kernel_text_address(addr) ? addr : 0; + if (!__kernel_text_address(addr)) { + printk_deferred_once(KERN_WARNING "WARNING: unrecognized kernel stack return address %p in %s:%d\n", + (void *)addr, state->task->comm, state->task->pid); + return 0; + } + + return addr; } EXPORT_SYMBOL_GPL(unwind_get_return_address); -- 2.7.4