From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756575Ab2JJNkJ (ORCPT ); Wed, 10 Oct 2012 09:40:09 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:7014 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756334Ab2JJNio (ORCPT ); Wed, 10 Oct 2012 09:38:44 -0400 X-Authority-Analysis: v=2.0 cv=e+uEuNV/ c=1 sm=0 a=rXTBtCOcEpjy1lPqhTCpEQ==:17 a=mNMOxpOpBa8A:10 a=Ciwy3NGCPMMA:10 a=Uznudo2c6VkA:10 a=5SG0PmZfjMsA:10 a=bbbx4UPp9XUA:10 a=meVymXHHAAAA:8 a=ICDzjrYLAOYA:10 a=VwQbUJbxAAAA:8 a=koDLa-P1KwdDXAu4Kc4A:9 a=Zh68SRI7RUMA:10 a=jeBq3FmKZ4MA:10 a=rXTBtCOcEpjy1lPqhTCpEQ==:117 X-Cloudmark-Score: 0 X-Originating-IP: 74.67.115.198 Message-Id: <20121010133843.211513401@goodmis.org> User-Agent: quilt/0.60-1 Date: Wed, 10 Oct 2012 09:38:06 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org, linux-rt-users Cc: Thomas Gleixner , Carsten Emde , John Kacur Subject: [PATCH RT 5/6] sched: Better debug output for might sleep References: <20121010133801.331863565@goodmis.org> Content-Disposition: inline; filename=0005-sched-Better-debug-output-for-might-sleep.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Thomas Gleixner might sleep can tell us where interrupts have been disabled, but we have no idea what disabled preemption. Add some debug infrastructure. Cc: stable-rt@vger.kernel.org Signed-off-by: Thomas Gleixner Signed-off-by: Steven Rostedt --- include/linux/sched.h | 4 ++++ kernel/sched.c | 23 +++++++++++++++++++++-- 2 files changed, 25 insertions(+), 2 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index 8155129..a179dd0 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1606,6 +1606,10 @@ struct task_struct { int kmap_idx; pte_t kmap_pte[KM_TYPE_NR]; #endif + +#ifdef CONFIG_DEBUG_PREEMPT + unsigned long preempt_disable_ip; +#endif }; #ifdef CONFIG_PREEMPT_RT_FULL diff --git a/kernel/sched.c b/kernel/sched.c index ea235b6..38f9104 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -4121,8 +4121,13 @@ void __kprobes add_preempt_count(int val) DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >= PREEMPT_MASK - 10); #endif - if (preempt_count() == val) - trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1)); + if (preempt_count() == val) { + unsigned long ip = get_parent_ip(CALLER_ADDR1); +#ifdef CONFIG_DEBUG_PREEMPT + current->preempt_disable_ip = ip; +#endif + trace_preempt_off(CALLER_ADDR0, ip); + } } EXPORT_SYMBOL(add_preempt_count); @@ -4164,6 +4169,13 @@ static noinline void __schedule_bug(struct task_struct *prev) print_modules(); if (irqs_disabled()) print_irqtrace_events(prev); +#ifdef DEBUG_PREEMPT + if (in_atomic_preempt_off()) { + pr_err("Preemption disabled at:"); + print_ip_sym(current->preempt_disable_ip); + pr_cont("\n"); + } +#endif if (regs) show_regs(regs); @@ -8483,6 +8495,13 @@ void __might_sleep(const char *file, int line, int preempt_offset) debug_show_held_locks(current); if (irqs_disabled()) print_irqtrace_events(current); +#ifdef DEBUG_PREEMPT + if (!preempt_count_equals(preempt_offset)) { + pr_err("Preemption disabled at:"); + print_ip_sym(current->preempt_disable_ip); + pr_cont("\n"); + } +#endif dump_stack(); #endif } -- 1.7.10.4