From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752426AbdLLLCh (ORCPT ); Tue, 12 Dec 2017 06:02:37 -0500 Received: from terminus.zytor.com ([65.50.211.136]:51243 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751434AbdLLLCg (ORCPT ); Tue, 12 Dec 2017 06:02:36 -0500 Date: Tue, 12 Dec 2017 02:58:03 -0800 From: tip-bot for Andrey Ryabinin Message-ID: Cc: hpa@zytor.com, peterz@infradead.org, linux-kernel@vger.kernel.org, aryabinin@virtuozzo.com, xiaolong.ye@intel.com, torvalds@linux-foundation.org, dvyukov@google.com, tglx@linutronix.de, fengguang.wu@intel.com, glider@google.com, jpoimboe@redhat.com, mingo@kernel.org Reply-To: hpa@zytor.com, peterz@infradead.org, xiaolong.ye@intel.com, torvalds@linux-foundation.org, linux-kernel@vger.kernel.org, aryabinin@virtuozzo.com, tglx@linutronix.de, dvyukov@google.com, glider@google.com, mingo@kernel.org, jpoimboe@redhat.com, fengguang.wu@intel.com In-Reply-To: <20171130123554.4330-1-aryabinin@virtuozzo.com> References: <20171130123554.4330-1-aryabinin@virtuozzo.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/urgent] x86/unwinder/guess: Prevent using CONFIG_UNWINDER_GUESS=y with CONFIG_STACKDEPOT=y Git-Commit-ID: 0a373d4fc248cb707821d7dad54ce6d5bcb0cdfe 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: 0a373d4fc248cb707821d7dad54ce6d5bcb0cdfe Gitweb: https://git.kernel.org/tip/0a373d4fc248cb707821d7dad54ce6d5bcb0cdfe Author: Andrey Ryabinin AuthorDate: Thu, 30 Nov 2017 15:35:54 +0300 Committer: Ingo Molnar CommitDate: Mon, 11 Dec 2017 19:07:07 +0100 x86/unwinder/guess: Prevent using CONFIG_UNWINDER_GUESS=y with CONFIG_STACKDEPOT=y Stackdepot doesn't work well with CONFIG_UNWINDER_GUESS=y. The 'guess' unwinder generate awfully large and inaccurate stacktraces, thus stackdepot can't deduplicate stacktraces because they all look like unique. Eventually stackdepot reaches its capacity limit: WARNING: CPU: 0 PID: 545 at lib/stackdepot.c:119 depot_save_stack+0x28e/0x550 Call Trace: ? kasan_kmalloc+0x144/0x160 ? depot_save_stack+0x1f5/0x550 ? do_raw_spin_unlock+0xda/0xf0 ? preempt_count_sub+0x13/0xc0 <...90 lines...> ? do_raw_spin_unlock+0xda/0xf0 Add a STACKDEPOT=n dependency to UNWINDER_GUESS to avoid the problem. Reported-by: kernel test robot Reported-by: Fengguang Wu Signed-off-by: Andrey Ryabinin Acked-by: Dmitry Vyukov Acked-by: Josh Poimboeuf Cc: Alexander Potapenko Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/20171130123554.4330-1-aryabinin@virtuozzo.com Signed-off-by: Ingo Molnar --- arch/x86/Kconfig.debug | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug index 6293a87..672441c 100644 --- a/arch/x86/Kconfig.debug +++ b/arch/x86/Kconfig.debug @@ -400,6 +400,7 @@ config UNWINDER_FRAME_POINTER config UNWINDER_GUESS bool "Guess unwinder" depends on EXPERT + depends on !STACKDEPOT ---help--- This option enables the "guess" unwinder for unwinding kernel stack traces. It scans the stack and reports every kernel text address it