From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933520AbcIOKmY (ORCPT ); Thu, 15 Sep 2016 06:42:24 -0400 Received: from terminus.zytor.com ([198.137.202.10]:38412 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754934AbcIOKmP (ORCPT ); Thu, 15 Sep 2016 06:42:15 -0400 Date: Thu, 15 Sep 2016 03:40:59 -0700 From: tip-bot for Josh Poimboeuf Message-ID: Cc: linux-kernel@vger.kernel.org, bp@alien8.de, mingo@kernel.org, dvlasenk@redhat.com, tglx@linutronix.de, rostedt@goodmis.org, luto@kernel.org, keescook@chromium.org, brgerst@gmail.com, hpa@zytor.com, fweisbec@gmail.com, jpoimboe@redhat.com, byungchul.park@lge.com, torvalds@linux-foundation.org, nilayvaish@gmail.com, peterz@infradead.org, luto@amacapital.net Reply-To: linux-kernel@vger.kernel.org, rostedt@goodmis.org, tglx@linutronix.de, dvlasenk@redhat.com, mingo@kernel.org, bp@alien8.de, nilayvaish@gmail.com, byungchul.park@lge.com, torvalds@linux-foundation.org, jpoimboe@redhat.com, hpa@zytor.com, brgerst@gmail.com, fweisbec@gmail.com, luto@kernel.org, keescook@chromium.org, luto@amacapital.net, peterz@infradead.org In-Reply-To: <5a5e5de92dcf11e8dc6b6e8e50ad7639d067830b.1473905218.git.jpoimboe@redhat.com> References: <5a5e5de92dcf11e8dc6b6e8e50ad7639d067830b.1473905218.git.jpoimboe@redhat.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/asm] x86/dumpstack: Add support for unwinding empty IRQ stacks Git-Commit-ID: 5fe599e02e41550c59831613a11c8ae057897c29 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: 5fe599e02e41550c59831613a11c8ae057897c29 Gitweb: http://git.kernel.org/tip/5fe599e02e41550c59831613a11c8ae057897c29 Author: Josh Poimboeuf AuthorDate: Wed, 14 Sep 2016 21:07:43 -0500 Committer: Ingo Molnar CommitDate: Thu, 15 Sep 2016 08:13:15 +0200 x86/dumpstack: Add support for unwinding empty IRQ stacks When an interrupt happens in entry code while running on a software IRQ stack, and the IRQ stack was empty, regs->sp will contain the stack end address (e.g., irq_stack_ptr). If the regs are passed to dump_trace(), get_stack_info() will report STACK_TYPE_UNKNOWN, causing dump_trace() to return prematurely without trying to go to the next stack. Update the bounds checking for software interrupt stacks so that the ending address is now considered part of the stack. This means that it's now possible for the 'walk_stack' callbacks -- print_context_stack() and print_context_stack_bp() -- to be called with an empty stack. But that's fine; they're already prepared to deal with that due to their on_stack() checks. Signed-off-by: Josh Poimboeuf Cc: Andy Lutomirski Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Byungchul Park Cc: Denys Vlasenko Cc: Frederic Weisbecker Cc: H. Peter Anvin Cc: Kees Cook Cc: Linus Torvalds Cc: Nilay Vaish Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/5a5e5de92dcf11e8dc6b6e8e50ad7639d067830b.1473905218.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar --- arch/x86/kernel/dumpstack_32.c | 12 ++++++++++-- arch/x86/kernel/dumpstack_64.c | 6 +++++- 2 files changed, 15 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/dumpstack_32.c b/arch/x86/kernel/dumpstack_32.c index c92da5a..50076d4 100644 --- a/arch/x86/kernel/dumpstack_32.c +++ b/arch/x86/kernel/dumpstack_32.c @@ -35,7 +35,11 @@ static bool in_hardirq_stack(unsigned long *stack, struct stack_info *info) unsigned long *begin = (unsigned long *)this_cpu_read(hardirq_stack); unsigned long *end = begin + (THREAD_SIZE / sizeof(long)); - if (stack < begin || stack >= end) + /* + * This is a software stack, so 'end' can be a valid stack pointer. + * It just means the stack is empty. + */ + if (stack < begin || stack > end) return false; info->type = STACK_TYPE_IRQ; @@ -56,7 +60,11 @@ static bool in_softirq_stack(unsigned long *stack, struct stack_info *info) unsigned long *begin = (unsigned long *)this_cpu_read(softirq_stack); unsigned long *end = begin + (THREAD_SIZE / sizeof(long)); - if (stack < begin || stack >= end) + /* + * This is a software stack, so 'end' can be a valid stack pointer. + * It just means the stack is empty. + */ + if (stack < begin || stack > end) return false; info->type = STACK_TYPE_SOFTIRQ; diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c index 41813ab..2e708af 100644 --- a/arch/x86/kernel/dumpstack_64.c +++ b/arch/x86/kernel/dumpstack_64.c @@ -90,7 +90,11 @@ static bool in_irq_stack(unsigned long *stack, struct stack_info *info) unsigned long *end = (unsigned long *)this_cpu_read(irq_stack_ptr); unsigned long *begin = end - (IRQ_STACK_SIZE / sizeof(long)); - if (stack < begin || stack >= end) + /* + * This is a software stack, so 'end' can be a valid stack pointer. + * It just means the stack is empty. + */ + if (stack < begin || stack > end) return false; info->type = STACK_TYPE_IRQ;