From: Zenghui Yu <yuzenghui@huawei.com>
To: <rostedt@goodmis.org>
Cc: <joel@joelfernandes.org>, <wanghaibin.wang@huawei.com>,
<linux-trace-devel@vger.kernel.org>,
Zenghui Yu <yuzenghui@huawei.com>
Subject: [PATCH] tracepoint: fix bad trace value in trace_kvm_exit()
Date: Wed, 28 Nov 2018 03:35:23 +0000 [thread overview]
Message-ID: <1543376123-23800-1-git-send-email-yuzenghui@huawei.com> (raw)
After enabling KVM event tracing, almost all of trace_kvm_exit()'s
printk shows
"kvm_exit: IRQ: ..."
even if the actual exception_type is NOT IRQ. More specifically,
trace_kvm_exit() is defined in virt/kvm/arm/trace.h by TRACE_EVENT.
This slight problem may have existed after commit e6753f23d961
("tracepoint: Make rcuidle tracepoint callers use SRCU"). There are
two variables in trace_kvm_exit() and __DO_TRACE() which have the
same name, *idx*. Thus the actual value of *idx* will be overwritten
when tracing. Fix it by adding a simple prefix.
Signed-off-by: Zenghui Yu <yuzenghui@huawei.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Wang Haibin <wanghaibin.wang@huawei.com>
Cc: linux-trace-devel@vger.kernel.org
---
include/linux/tracepoint.h | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
index 538ba1a..e9de8ad 100644
--- a/include/linux/tracepoint.h
+++ b/include/linux/tracepoint.h
@@ -166,7 +166,7 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p)
struct tracepoint_func *it_func_ptr; \
void *it_func; \
void *__data; \
- int __maybe_unused idx = 0; \
+ int __maybe_unused __idx = 0; \
\
if (!(cond)) \
return; \
@@ -182,7 +182,7 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p)
* doesn't work from the idle path. \
*/ \
if (rcuidle) { \
- idx = srcu_read_lock_notrace(&tracepoint_srcu); \
+ __idx = srcu_read_lock_notrace(&tracepoint_srcu);\
rcu_irq_enter_irqson(); \
} \
\
@@ -198,7 +198,7 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p)
\
if (rcuidle) { \
rcu_irq_exit_irqson(); \
- srcu_read_unlock_notrace(&tracepoint_srcu, idx);\
+ srcu_read_unlock_notrace(&tracepoint_srcu, __idx);\
} \
\
preempt_enable_notrace(); \
--
1.8.3.1
next reply other threads:[~2018-11-28 14:44 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-28 3:35 Zenghui Yu [this message]
2018-11-28 3:54 ` [PATCH] tracepoint: fix bad trace value in trace_kvm_exit() Steven Rostedt
2018-11-29 2:21 ` Zenghui Yu
2018-11-29 2:34 ` Steven Rostedt
2018-11-30 2:18 ` Joel Fernandes
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