>From 2c06e795162cb306c9707ec51d3e1deadb37f573 Mon Sep 17 00:00:00 2001
From: Dennis Zhou <dennisz@xxxxxx>
Date: Wed, 21 Jun 2017 10:17:09 -0700
Commit 30a5b5367ef9 ("percpu: expose statistics about percpu memory via
debugfs") introduces percpu memory statistics. pcpu_stats_chunk_alloc
takes the spin lock and disables/enables irqs on creation of a chunk. Irqs
are not enabled when the first chunk is initialized and thus kernels are
failing to boot with kernel debugging enabled. Fixed by changing _irq to
_irqsave and _irqrestore.
Fixes: 30a5b5367ef9 ("percpu: expose statistics about percpu memory via debugfs")
Signed-off-by: Dennis Zhou <dennisz@xxxxxx>
Reported-by: Alexander Levin <alexander.levin@xxxxxxxxxxx>
---
Hi Sasha,
The root cause was from 0003 of that series where I prematurely enabled
irqs and the problem is addresssed here. I am able to boot with debug
options enabled.
Thanks,
Dennis
mm/percpu-internal.h | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/mm/percpu-internal.h b/mm/percpu-internal.h
index d030fce..cd2442e 100644
--- a/mm/percpu-internal.h
+++ b/mm/percpu-internal.h
@@ -116,13 +116,14 @@ static inline void pcpu_stats_area_dealloc(struct pcpu_chunk *chunk)
*/
static inline void pcpu_stats_chunk_alloc(void)
{
- spin_lock_irq(&pcpu_lock);
+ unsigned long flags;
+ spin_lock_irqsave(&pcpu_lock, flags);
pcpu_stats.nr_chunks++;
pcpu_stats.nr_max_chunks =
max(pcpu_stats.nr_max_chunks, pcpu_stats.nr_chunks);
- spin_unlock_irq(&pcpu_lock);
+ spin_unlock_irqrestore(&pcpu_lock, flags);
}
/*
@@ -130,11 +131,12 @@ static inline void pcpu_stats_chunk_alloc(void)
*/
static inline void pcpu_stats_chunk_dealloc(void)
{
- spin_lock_irq(&pcpu_lock);
+ unsigned long flags;
+ spin_lock_irqsave(&pcpu_lock, flags);
pcpu_stats.nr_chunks--;
- spin_unlock_irq(&pcpu_lock);
+ spin_unlock_irqrestore(&pcpu_lock, flags);
}
#else
--
2.9.3
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
