From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753300Ab1KRXhz (ORCPT ); Fri, 18 Nov 2011 18:37:55 -0500 Received: from terminus.zytor.com ([198.137.202.10]:53404 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751083Ab1KRXhy (ORCPT ); Fri, 18 Nov 2011 18:37:54 -0500 Date: Fri, 18 Nov 2011 15:37:40 -0800 From: tip-bot for Peter Zijlstra Message-ID: Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@redhat.com, a.p.zijlstra@chello.nl, tglx@linutronix.de, mingo@elte.hu Reply-To: mingo@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, a.p.zijlstra@chello.nl, tglx@linutronix.de, mingo@elte.hu To: linux-tip-commits@vger.kernel.org Subject: [tip:core/printk] printk, lockdep: Disable lock debugging on zap_locks() Git-Commit-ID: 94d24fc47219219b5aa23b45956cc37ee5aa5b01 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.6 (terminus.zytor.com [127.0.0.1]); Fri, 18 Nov 2011 15:37:46 -0800 (PST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 94d24fc47219219b5aa23b45956cc37ee5aa5b01 Gitweb: http://git.kernel.org/tip/94d24fc47219219b5aa23b45956cc37ee5aa5b01 Author: Peter Zijlstra AuthorDate: Tue, 7 Jun 2011 11:17:30 +0200 Committer: Ingo Molnar CommitDate: Mon, 14 Nov 2011 13:35:16 +0100 printk, lockdep: Disable lock debugging on zap_locks() zap_locks() is used by printk() in a last ditch effort to get data out, clearly we cannot trust lock state after this so make it disable lock debugging. Also don't treat printk recursion through lockdep as a normal recursion bug but try hard to get the lockdep splat out. Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/n/tip-kqxwmo4xz37e1s8w0xopvr0q@git.kernel.org Signed-off-by: Ingo Molnar --- include/linux/lockdep.h | 4 ++++ kernel/printk.c | 3 ++- 2 files changed, 6 insertions(+), 1 deletions(-) diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h index b6a56e3..d36619e 100644 --- a/include/linux/lockdep.h +++ b/include/linux/lockdep.h @@ -343,6 +343,8 @@ extern void lockdep_trace_alloc(gfp_t mask); #define lockdep_assert_held(l) WARN_ON(debug_locks && !lockdep_is_held(l)) +#define lockdep_recursing(tsk) ((tsk)->lockdep_recursion) + #else /* !LOCKDEP */ static inline void lockdep_off(void) @@ -392,6 +394,8 @@ struct lock_class_key { }; #define lockdep_assert_held(l) do { } while (0) +#define lockdep_recursing(tsk) (0) + #endif /* !LOCKDEP */ #ifdef CONFIG_LOCK_STAT diff --git a/kernel/printk.c b/kernel/printk.c index 1455a0d..6d08794 100644 --- a/kernel/printk.c +++ b/kernel/printk.c @@ -688,6 +688,7 @@ static void zap_locks(void) oops_timestamp = jiffies; + debug_locks_off(); /* If a crash is occurring, make sure we can't deadlock */ raw_spin_lock_init(&logbuf_lock); /* And make sure that we print immediately */ @@ -856,7 +857,7 @@ asmlinkage int vprintk(const char *fmt, va_list args) * recursion and return - but flag the recursion so that * it can be printed at the next appropriate moment: */ - if (!oops_in_progress) { + if (!oops_in_progress && !lockdep_recursing(current)) { recursion_bug = 1; goto out_restore_irqs; }