From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752722AbdH2NJz (ORCPT ); Tue, 29 Aug 2017 09:09:55 -0400 Received: from terminus.zytor.com ([65.50.211.136]:48193 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751566AbdH2NJx (ORCPT ); Tue, 29 Aug 2017 09:09:53 -0400 Date: Tue, 29 Aug 2017 06:04:12 -0700 From: tip-bot for Ingo Molnar Message-ID: Cc: arnd@arndb.de, linux-kernel@vger.kernel.org, tglx@linutronix.de, keescook@chromium.org, riel@redhat.com, efault@gmx.de, dave@stgolabs.net, peterz@infradead.org, mingo@kernel.org, elena.reshetova@intel.com, jpoimboe@redhat.com, torvalds@linux-foundation.org, hpa@zytor.com Reply-To: dave@stgolabs.net, riel@redhat.com, efault@gmx.de, elena.reshetova@intel.com, peterz@infradead.org, mingo@kernel.org, jpoimboe@redhat.com, torvalds@linux-foundation.org, hpa@zytor.com, arnd@arndb.de, tglx@linutronix.de, linux-kernel@vger.kernel.org, keescook@chromium.org In-Reply-To: References: To: linux-tip-commits@vger.kernel.org Subject: [tip:locking/core] locking/refcounts, x86/asm: Disable CONFIG_ARCH_HAS_REFCOUNT for the time being Git-Commit-ID: 7b3d61cc73a1abe4c2c7eaf00093b338c8b233b0 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: 7b3d61cc73a1abe4c2c7eaf00093b338c8b233b0 Gitweb: http://git.kernel.org/tip/7b3d61cc73a1abe4c2c7eaf00093b338c8b233b0 Author: Ingo Molnar AuthorDate: Tue, 29 Aug 2017 13:10:35 +0200 Committer: Ingo Molnar CommitDate: Tue, 29 Aug 2017 13:10:35 +0200 locking/refcounts, x86/asm: Disable CONFIG_ARCH_HAS_REFCOUNT for the time being Mike Galbraith bisected a boot crash back to the following commit: 7a46ec0e2f48 ("locking/refcounts, x86/asm: Implement fast refcount overflow protection") The crash/hang pattern is: > Symptom is a few splats as below, with box finally hanging. Network > comes up, but neither ssh nor console login is possible. > > ------------[ cut here ]------------ > WARNING: CPU: 4 PID: 0 at net/netlink/af_netlink.c:374 netlink_sock_destruct+0x82/0xa0 > ... > __sk_destruct() > rcu_process_callbacks() > __do_softirq() > irq_exit() > smp_apic_timer_interrupt() > apic_timer_interrupt() We are at -rc7 already, and the code has grown some dependencies, so instead of a plain revert disable the config temporarily, in the hope of getting real fixes. Reported-by: Mike Galbraith Tested-by: Mike Galbraith Cc: Arnd Bergmann Cc: Davidlohr Bueso Cc: Elena Reshetova Cc: Josh Poimboeuf Cc: Kees Cook Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Rik van Riel Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/tip-7a46ec0e2f4850407de5e1d19a44edee6efa58ec@git.kernel.org Signed-off-by: Ingo Molnar --- arch/x86/Kconfig | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 6e01f58..efd9df5 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -55,7 +55,8 @@ config X86 select ARCH_HAS_KCOV if X86_64 select ARCH_HAS_MMIO_FLUSH select ARCH_HAS_PMEM_API if X86_64 - select ARCH_HAS_REFCOUNT + # Causing hangs/crashes, see the commit that added this change for details. + select ARCH_HAS_REFCOUNT if BROKEN select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 select ARCH_HAS_SET_MEMORY select ARCH_HAS_SG_CHAIN