| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.4 52/57] tracing: Use SOFTIRQ_OFFSET for softirq dectection for more accurate results | Date | Wed, 19 Jul 2017 13:12:58 +0200 |
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4.4-stable review patch. If anyone has any objections, please let me know.
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From: Pavankumar Kondeti <pkondeti@codeaurora.org>
commit c59f29cb144a6a0dfac16ede9dc8eafc02dc56ca upstream.
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> Signed-off-by: Amit Pundir <amit.pundir@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- kernel/trace/trace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -1660,7 +1660,7 @@ tracing_generic_entry_update(struct trac 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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