[for-next][PATCH 1/5] tracing: Use SOFTIRQ_OFFSET for softirq dectection for more accurate results

From	Steven Rostedt <rostedt@goodmis.org>
Newsgroups	linux.kernel
Subject	[for-next][PATCH 1/5] tracing: Use SOFTIRQ_OFFSET for softirq dectection for more accurate results
Date	2016-12-13 17:20 +0100
Message-ID	<sNXY5-3ll-9@gated-at.bofh.it> (permalink)
References	<sNXY5-3ll-3@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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From: Pavankumar Kondeti <pkondeti@codeaurora.org>

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.

Link: http://lkml.kernel.org/r/1481300417-3564-1-git-send-email-pkondeti@codeaurora.org

Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 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 6f420d7b703b..970aafe80b49 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1949,7 +1949,7 @@ tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags,
 #endif
 		((pc & NMI_MASK    ) ? TRACE_FLAG_NMI     : 0) |
 		((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);
 }
-- 
2.10.2

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[for-next][PATCH 1/5] tracing: Use SOFTIRQ_OFFSET for softirq dectection for more accurate  results Steven Rostedt <rostedt@goodmis.org> - 2016-12-13 17:20 +0100

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