2016-12-07 03:38:47

by Pavankumar Kondeti

[permalink] [raw]
Subject: [PATCH] tracing: fix "softirq" flag detection

The 's' flag is supposed to indicate that a softirq is running. This
can be detected by testing the preempt_count with SOFTIRQ_OFFSET.

The current code tests the preempt_count with SOFTIRQ_MASK, which
would be true even when softirqs are disabled but not serving a
softirq.

Change-Id: I084531ce806e0f7d42a38be0a7ad45977c43d158
Signed-off-by: Pavankumar Kondeti <[email protected]>
---
kernel/trace/trace.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index ae68222..1d0f1a1 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1685,7 +1685,7 @@ tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags,
TRACE_FLAG_IRQS_NOSUPPORT |
#endif
((pc & HARDIRQ_MASK) ? TRACE_FLAG_HARDIRQ : 0) |
- ((pc & SOFTIRQ_MASK) ? TRACE_FLAG_SOFTIRQ : 0) |
+ ((pc & SOFTIRQ_OFFSET) ? TRACE_FLAG_SOFTIRQ : 0) |
(tif_need_resched() ? TRACE_FLAG_NEED_RESCHED : 0) |
(test_preempt_need_resched() ? TRACE_FLAG_PREEMPT_RESCHED : 0);
}
--
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