80 lines
2.3 KiB
Diff
80 lines
2.3 KiB
Diff
From e30e64f60b466d52be57bfd243efe9bd1feb7df5 Mon Sep 17 00:00:00 2001
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From: Thomas Gleixner <tglx@linutronix.de>
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Date: Fri, 5 Oct 2012 08:56:15 +0100
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Subject: [PATCH 284/290] sched: Better debug output for might sleep
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might sleep can tell us where interrupts have been disabled, but we
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have no idea what disabled preemption. Add some debug infrastructure.
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Cc: stable-rt@vger.kernel.org
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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---
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include/linux/sched.h | 4 ++++
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kernel/sched.c | 23 +++++++++++++++++++++--
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2 files changed, 25 insertions(+), 2 deletions(-)
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diff --git a/include/linux/sched.h b/include/linux/sched.h
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index 03498cc..12317b6 100644
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--- a/include/linux/sched.h
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+++ b/include/linux/sched.h
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@@ -1612,6 +1612,10 @@ struct task_struct {
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int kmap_idx;
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pte_t kmap_pte[KM_TYPE_NR];
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#endif
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+
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+#ifdef CONFIG_DEBUG_PREEMPT
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+ unsigned long preempt_disable_ip;
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+#endif
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};
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#ifdef CONFIG_PREEMPT_RT_FULL
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diff --git a/kernel/sched.c b/kernel/sched.c
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index 87654e6..cdf9484 100644
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--- a/kernel/sched.c
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+++ b/kernel/sched.c
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@@ -4487,8 +4487,13 @@ void __kprobes add_preempt_count(int val)
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DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >=
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PREEMPT_MASK - 10);
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#endif
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- if (preempt_count() == val)
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- trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
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+ if (preempt_count() == val) {
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+ unsigned long ip = get_parent_ip(CALLER_ADDR1);
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+#ifdef CONFIG_DEBUG_PREEMPT
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+ current->preempt_disable_ip = ip;
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+#endif
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+ trace_preempt_off(CALLER_ADDR0, ip);
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+ }
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}
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EXPORT_SYMBOL(add_preempt_count);
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@@ -4530,6 +4535,13 @@ static noinline void __schedule_bug(struct task_struct *prev)
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print_modules();
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if (irqs_disabled())
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print_irqtrace_events(prev);
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+#ifdef DEBUG_PREEMPT
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+ if (in_atomic_preempt_off()) {
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+ pr_err("Preemption disabled at:");
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+ print_ip_sym(current->preempt_disable_ip);
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+ pr_cont("\n");
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+ }
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+#endif
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if (regs)
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show_regs(regs);
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@@ -8912,6 +8924,13 @@ void __might_sleep(const char *file, int line, int preempt_offset)
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debug_show_held_locks(current);
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if (irqs_disabled())
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print_irqtrace_events(current);
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+#ifdef DEBUG_PREEMPT
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+ if (!preempt_count_equals(preempt_offset)) {
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+ pr_err("Preemption disabled at:");
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+ print_ip_sym(current->preempt_disable_ip);
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+ pr_cont("\n");
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+ }
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+#endif
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dump_stack();
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}
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EXPORT_SYMBOL(__might_sleep);
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