[PATCH] trace: fix missing assignment in trace_ctxwake_*

[PATCH] trace: fix missing assignment in trace_ctxwake_*

[Hiroshi Shimamoto]

From: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>

The state char variable S should be reassigned, if S == 0.

Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
---
 kernel/trace/trace_output.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index f572f44..cda766f 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -883,7 +883,7 @@ static int trace_ctxwake_raw(struct trace_iterator *iter, char S)
 	trace_assign_type(field, iter->ent);
 
 	if (!S)
-		task_state_char(field->prev_state);
+		S = task_state_char(field->prev_state);
 	T = task_state_char(field->next_state);
 	if (!trace_seq_printf(&iter->seq, "%d %d %c %d %d %d %c\n",
 			      field->prev_pid,
@@ -918,7 +918,7 @@ static int trace_ctxwake_hex(struct trace_iterator *iter, char S)
 	trace_assign_type(field, iter->ent);
 
 	if (!S)
-		task_state_char(field->prev_state);
+		S = task_state_char(field->prev_state);
 	T = task_state_char(field->next_state);
 
 	SEQ_PUT_HEX_FIELD_RET(s, field->prev_pid);
-- 
1.6.3.3

Re: [PATCH] trace: fix missing assignment in trace_ctxwake_*

[Frédéric Weisbecker]

2009/10/1 Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>:
> From: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
>
> The state char variable S should be reassigned, if S == 0.
>
> Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>


Good catch, we are indeed missing the state of the task that is going to sleep
for the context switch events (in the raw mode).

Acked-by: Frederic Weisbecker <fweisbec@gmail.com>

Fortunately the problem arises with the sched_switch/wake_up  tracers, not
the sched trace events.
The formers are legacy now. But still, that was buggy.

Thanks.

[tip:tracing/urgent] trace: Fix missing assignment in trace_ctxwake_*

[tip-bot for Hiroshi Shimamoto]

Commit-ID:  a2067f64cb59dfb19940a1a38a5a9fa6f2ddcaa5
Gitweb:     http://git.kernel.org/tip/a2067f64cb59dfb19940a1a38a5a9fa6f2ddcaa5
Author:     Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
AuthorDate: Thu, 1 Oct 2009 13:33:28 +0900
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Fri, 2 Oct 2009 15:24:55 +0200

trace: Fix missing assignment in trace_ctxwake_*

The state char variable S should be reassigned, if S == 0.

We are missing the state of the task that is going to sleep for the
context switch events (in the raw mode).

Fortunately the problem arises with the sched_switch/wake_up
tracers, not the sched trace events.

The formers are legacy now. But still, that was buggy.

Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4AC43118.6050409@ct.jp.nec.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>


---
 kernel/trace/trace_output.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index f572f44..cda766f 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -883,7 +883,7 @@ static int trace_ctxwake_raw(struct trace_iterator *iter, char S)
 	trace_assign_type(field, iter->ent);
 
 	if (!S)
-		task_state_char(field->prev_state);
+		S = task_state_char(field->prev_state);
 	T = task_state_char(field->next_state);
 	if (!trace_seq_printf(&iter->seq, "%d %d %c %d %d %d %c\n",
 			      field->prev_pid,
@@ -918,7 +918,7 @@ static int trace_ctxwake_hex(struct trace_iterator *iter, char S)
 	trace_assign_type(field, iter->ent);
 
 	if (!S)
-		task_state_char(field->prev_state);
+		S = task_state_char(field->prev_state);
 	T = task_state_char(field->next_state);
 
 	SEQ_PUT_HEX_FIELD_RET(s, field->prev_pid);

[tip:tracing/urgent] trace: Fix missing assignment in trace_ctxwake_*

[tip-bot for Hiroshi Shimamoto]

Commit-ID:  b0f56f1a63b7b968e6feeeefeace24bc8e0a4a65
Gitweb:     http://git.kernel.org/tip/b0f56f1a63b7b968e6feeeefeace24bc8e0a4a65
Author:     Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
AuthorDate: Thu, 1 Oct 2009 13:33:28 +0900
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Tue, 6 Oct 2009 14:28:24 +0200

trace: Fix missing assignment in trace_ctxwake_*

The state char variable S should be reassigned, if S == 0.

We are missing the state of the task that is going to sleep for the
context switch events (in the raw mode).

Fortunately the problem arises with the sched_switch/wake_up
tracers, not the sched trace events.

The formers are legacy now. But still, that was buggy.

Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4AC43118.6050409@ct.jp.nec.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 kernel/trace/trace_output.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index f572f44..cda766f 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -883,7 +883,7 @@ static int trace_ctxwake_raw(struct trace_iterator *iter, char S)
 	trace_assign_type(field, iter->ent);
 
 	if (!S)
-		task_state_char(field->prev_state);
+		S = task_state_char(field->prev_state);
 	T = task_state_char(field->next_state);
 	if (!trace_seq_printf(&iter->seq, "%d %d %c %d %d %d %c\n",
 			      field->prev_pid,
@@ -918,7 +918,7 @@ static int trace_ctxwake_hex(struct trace_iterator *iter, char S)
 	trace_assign_type(field, iter->ent);
 
 	if (!S)
-		task_state_char(field->prev_state);
+		S = task_state_char(field->prev_state);
 	T = task_state_char(field->next_state);
 
 	SEQ_PUT_HEX_FIELD_RET(s, field->prev_pid);