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[PATCH 2/2] lockdep reentrancy
- From: Mathieu Desnoyers <mathieu dot desnoyers at polymtl dot ca>
- To: Ingo Molnar <mingo at redhat dot com>
- Cc: Andrew Morton <akpm at osdl dot org>, Greg Kroah-Hartman <gregkh at suse dot de>, Christoph Hellwig <hch at infradead dot org>, linux-kernel at vger dot kernel dot org, ltt-dev at shafik dot org, "Martin J. Bligh" <mbligh at mbligh dot org>, Douglas Niehaus <niehaus at eecs dot ku dot edu>, systemtap at sources dot redhat dot com, Thomas Gleixner <tglx at linutronix dot de>, Richard J Moore <richardj_moore at uk dot ibm dot com>
- Date: Tue, 16 Jan 2007 12:56:31 -0500
- Subject: [PATCH 2/2] lockdep reentrancy
- References: <20061220235216.GA28643@Krystal> <OFAB3D8A6C.1643F2D3-ON80257262.000581E4-80257262.00088F04@uk.ibm.com>
Here is a patch to lockdep.c so it behaves correctly when a kprobe breakpoint is
put on a marker within hardirq tracing functions as long as the marker is within
the lockdep_recursion incremented boundaries. It should apply on
2.6.20-rc4-git3.
Mathieu
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
@@ -1841,33 +1843,36 @@ void trace_hardirqs_on(void)
struct task_struct *curr = current;
unsigned long ip;
if (unlikely(!debug_locks || current->lockdep_recursion))
return;
+ current->lockdep_recursion++;
+ barrier();
+
if (DEBUG_LOCKS_WARN_ON(unlikely(!early_boot_irqs_enabled)))
- return;
+ goto end;
if (unlikely(curr->hardirqs_enabled)) {
debug_atomic_inc(&redundant_hardirqs_on);
- return;
+ goto end;
}
/* we'll do an OFF -> ON transition: */
curr->hardirqs_enabled = 1;
ip = (unsigned long) __builtin_return_address(0);
if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
- return;
+ goto end;
if (DEBUG_LOCKS_WARN_ON(current->hardirq_context))
- return;
+ goto end;
/*
* We are going to turn hardirqs on, so set the
* usage bit for all held locks:
*/
if (!mark_held_locks(curr, 1, ip))
- return;
+ goto end;
/*
* If we have softirqs enabled, then set the usage
* bit for all held locks. (disabled hardirqs prevented
@@ -1875,11 +1880,14 @@ void trace_hardirqs_on(void)
*/
if (curr->softirqs_enabled)
if (!mark_held_locks(curr, 0, ip))
- return;
+ goto end;
curr->hardirq_enable_ip = ip;
curr->hardirq_enable_event = ++curr->irq_events;
debug_atomic_inc(&hardirqs_on_events);
+end:
+ barrier();
+ current->lockdep_recursion--;
}
EXPORT_SYMBOL(trace_hardirqs_on);
@@ -1888,14 +1896,17 @@ void trace_hardirqs_off(void)
{
struct task_struct *curr = current;
if (unlikely(!debug_locks || current->lockdep_recursion))
return;
+ current->lockdep_recursion++;
+ barrier();
+
if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
- return;
+ goto end;
if (curr->hardirqs_enabled) {
/*
@@ -1910,6 +1921,9 @@ void trace_hardirqs_off(void)
debug_atomic_inc(&hardirqs_off_events);
} else
debug_atomic_inc(&redundant_hardirqs_off);
+end:
+ barrier();
+ current->lockdep_recursion--;
}
EXPORT_SYMBOL(trace_hardirqs_off);
--
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