From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935364AbcJ0HkI (ORCPT ); Thu, 27 Oct 2016 03:40:08 -0400 Received: from terminus.zytor.com ([198.137.202.10]:54746 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933572AbcJ0HkF (ORCPT ); Thu, 27 Oct 2016 03:40:05 -0400 Date: Thu, 27 Oct 2016 00:37:36 -0700 From: tip-bot for Josh Poimboeuf Message-ID: Cc: torvalds@linux-foundation.org, jpoimboe@redhat.com, tglx@linutronix.de, dvlasenk@redhat.com, luto@kernel.org, peterz@infradead.org, linux-kernel@vger.kernel.org, brgerst@gmail.com, mingo@kernel.org, hpa@zytor.com, bp@alien8.de Reply-To: mingo@kernel.org, brgerst@gmail.com, linux-kernel@vger.kernel.org, peterz@infradead.org, bp@alien8.de, hpa@zytor.com, luto@kernel.org, dvlasenk@redhat.com, tglx@linutronix.de, torvalds@linux-foundation.org, jpoimboe@redhat.com In-Reply-To: <03c888f6f7414d54fa56b393ea25482be6899b5f.1477496147.git.jpoimboe@redhat.com> References: <03c888f6f7414d54fa56b393ea25482be6899b5f.1477496147.git.jpoimboe@redhat.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/asm] x86/unwind: Warn on bad frame pointer Git-Commit-ID: c32c47c68a0ae701088c5b2c3798856ed16746ae X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: c32c47c68a0ae701088c5b2c3798856ed16746ae Gitweb: http://git.kernel.org/tip/c32c47c68a0ae701088c5b2c3798856ed16746ae Author: Josh Poimboeuf AuthorDate: Wed, 26 Oct 2016 10:41:48 -0500 Committer: Ingo Molnar CommitDate: Thu, 27 Oct 2016 08:32:37 +0200 x86/unwind: Warn on bad frame pointer Detect situations in the unwinder where the frame pointer refers to a bad address, and print an appropriate warning. 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 Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/03c888f6f7414d54fa56b393ea25482be6899b5f.1477496147.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar --- arch/x86/kernel/unwind_frame.c | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/unwind_frame.c b/arch/x86/kernel/unwind_frame.c index 5795427..9be9a8f 100644 --- a/arch/x86/kernel/unwind_frame.c +++ b/arch/x86/kernel/unwind_frame.c @@ -123,8 +123,17 @@ bool unwind_next_frame(struct unwind_state *state) } /* make sure the next frame's data is accessible */ - if (!update_stack_state(state, next_frame, next_len)) - return false; + if (!update_stack_state(state, next_frame, next_len)) { + /* + * Don't warn on bad regs->bp. An interrupt in entry code + * might cause a false positive warning. + */ + if (state->regs) + goto the_end; + + goto bad_address; + } + /* move to the next frame */ if (regs) { state->regs = regs; @@ -136,6 +145,11 @@ bool unwind_next_frame(struct unwind_state *state) return true; +bad_address: + printk_deferred_once(KERN_WARNING + "WARNING: kernel stack frame pointer at %p in %s:%d has bad value %p\n", + state->bp, state->task->comm, + state->task->pid, next_bp); the_end: state->stack_info.type = STACK_TYPE_UNKNOWN; return false;