2009-10-07 08:22:08

by helight.xu

Subject: [PATCH V2] fix a warning on kernel/trace/trace_branch.c and trace_hw_branches.c

fix warnings that caused the API change of trace_buffer_lock_reserve()
change files: kernel/trace/trace_hw_branch.c
kernel/trace/trace_branch.c

Signed-off-by: Zhenwen Xu <[email protected]>
---
kernel/trace/trace_branch.c | 2 +-
kernel/trace/trace_hw_branches.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/trace/trace_branch.c b/kernel/trace/trace_branch.c
index 7a7a9fd..216e2dd 100644
--- a/kernel/trace/trace_branch.c
+++ b/kernel/trace/trace_branch.c
@@ -54,7 +54,7 @@ probe_likely_condition(struct ftrace_branch_data *f, int val, int expect)
goto out;

pc = preempt_count();
- event = trace_buffer_lock_reserve(tr, TRACE_BRANCH,
+ event = trace_buffer_lock_reserve(tr->buffer, TRACE_BRANCH,
sizeof(*entry), flags, pc);
if (!event)
goto out;
diff --git a/kernel/trace/trace_hw_branches.c b/kernel/trace/trace_hw_branches.c
index 23b6385..1cc17ca 100644
--- a/kernel/trace/trace_hw_branches.c
+++ b/kernel/trace/trace_hw_branches.c
@@ -180,7 +180,7 @@ void trace_hw_branch(u64 from, u64 to)
if (atomic_inc_return(&tr->data[cpu]->disabled) != 1)
goto out;

- event = trace_buffer_lock_reserve(tr, TRACE_HW_BRANCHES,
+ event = trace_buffer_lock_reserve(tr->buffer, TRACE_HW_BRANCHES,
sizeof(*entry), 0, 0);
if (!event)
goto out;
--
1.6.3.3

--
--------------------------------
http://zhwen.org - Open and Free

2009-10-07 08:55:34

by Li Zefan

Subject: Re: [PATCH V2] fix a warning on kernel/trace/trace_branch.c and trace_hw_branches.c

Zhenwen Xu wrote:
> fix warnings that caused the API change of trace_buffer_lock_reserve()
> change files: kernel/trace/trace_hw_branch.c
> kernel/trace/trace_branch.c
>

Hmm, did you really compile trace_hw_branch.c while testing
this patch?

This change is necessary too:

- trace_buffer_unlock_commit(tr, event, 0, 0);
+ trace_buffer_unlock_commit(tr->buffer, event, 0, 0);

And use a varaible "buffer = tr->buffer" should be better.

> Signed-off-by: Zhenwen Xu <[email protected]>
> ---
> kernel/trace/trace_branch.c | 2 +-
> kernel/trace/trace_hw_branches.c | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/trace/trace_branch.c b/kernel/trace/trace_branch.c
> index 7a7a9fd..216e2dd 100644
> --- a/kernel/trace/trace_branch.c
> +++ b/kernel/trace/trace_branch.c
> @@ -54,7 +54,7 @@ probe_likely_condition(struct ftrace_branch_data *f, int val, int expect)
> goto out;
>
> pc = preempt_count();
> - event = trace_buffer_lock_reserve(tr, TRACE_BRANCH,
> + event = trace_buffer_lock_reserve(tr->buffer, TRACE_BRANCH,
> sizeof(*entry), flags, pc);
> if (!event)
> goto out;
> diff --git a/kernel/trace/trace_hw_branches.c b/kernel/trace/trace_hw_branches.c
> index 23b6385..1cc17ca 100644
> --- a/kernel/trace/trace_hw_branches.c
> +++ b/kernel/trace/trace_hw_branches.c
> @@ -180,7 +180,7 @@ void trace_hw_branch(u64 from, u64 to)
> if (atomic_inc_return(&tr->data[cpu]->disabled) != 1)
> goto out;
>
> - event = trace_buffer_lock_reserve(tr, TRACE_HW_BRANCHES,
> + event = trace_buffer_lock_reserve(tr->buffer, TRACE_HW_BRANCHES,
> sizeof(*entry), 0, 0);
> if (!event)
> goto out;

2009-10-07 11:42:57

by helight.xu

Subject: Re: [PATCH V2] fix a warning on kernel/trace/trace_branch.c and trace_hw_branches.c

Li Zefan wrote:
> Zhenwen Xu wrote:
>
>> fix warnings that caused the API change of trace_buffer_lock_reserve()
>> change files: kernel/trace/trace_hw_branch.c
>> kernel/trace/trace_branch.c
>>
>>
>
> Hmm, did you really compile trace_hw_branch.c while testing
> this patch?
>
> This change is necessary too:
>
> - trace_buffer_unlock_commit(tr, event, 0, 0);
> + trace_buffer_unlock_commit(tr->buffer, event, 0, 0);
>
> And use a varaible "buffer = tr->buffer" should be better.
>
oh! sorry for my careless!
>
>> Signed-off-by: Zhenwen Xu <[email protected]>
>> ---
>> kernel/trace/trace_branch.c | 2 +-
>> kernel/trace/trace_hw_branches.c | 2 +-
>> 2 files changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/kernel/trace/trace_branch.c b/kernel/trace/trace_branch.c
>> index 7a7a9fd..216e2dd 100644
>> --- a/kernel/trace/trace_branch.c
>> +++ b/kernel/trace/trace_branch.c
>> @@ -54,7 +54,7 @@ probe_likely_condition(struct ftrace_branch_data *f, int val, int expect)
>> goto out;
>>
>> pc = preempt_count();
>> - event = trace_buffer_lock_reserve(tr, TRACE_BRANCH,
>> + event = trace_buffer_lock_reserve(tr->buffer, TRACE_BRANCH,
>> sizeof(*entry), flags, pc);
>> if (!event)
>> goto out;
>> diff --git a/kernel/trace/trace_hw_branches.c b/kernel/trace/trace_hw_branches.c
>> index 23b6385..1cc17ca 100644
>> --- a/kernel/trace/trace_hw_branches.c
>> +++ b/kernel/trace/trace_hw_branches.c
>> @@ -180,7 +180,7 @@ void trace_hw_branch(u64 from, u64 to)
>> if (atomic_inc_return(&tr->data[cpu]->disabled) != 1)
>> goto out;
>>
>> - event = trace_buffer_lock_reserve(tr, TRACE_HW_BRANCHES,
>> + event = trace_buffer_lock_reserve(tr->buffer, TRACE_HW_BRANCHES,
>> sizeof(*entry), 0, 0);
>> if (!event)
>> goto out;
>>
>
>


--
---------------------------------
Zhenwen Xu - Open and Free
Home Page: http://zhwen.org

2009-10-07 13:48:21

by Steven Rostedt

Subject: Re: [PATCH V2] fix a warning on kernel/trace/trace_branch.c and trace_hw_branches.c

On Wed, 2009-10-07 at 19:40 +0800, Helight.Xu wrote:
> Li Zefan wrote:
> > Zhenwen Xu wrote:
> >
> >> fix warnings that caused the API change of trace_buffer_lock_reserve()
> >> change files: kernel/trace/trace_hw_branch.c
> >> kernel/trace/trace_branch.c
> >>
> >>
> >
> > Hmm, did you really compile trace_hw_branch.c while testing
> > this patch?
> >
> > This change is necessary too:
> >
> > - trace_buffer_unlock_commit(tr, event, 0, 0);
> > + trace_buffer_unlock_commit(tr->buffer, event, 0, 0);
> >
> > And use a varaible "buffer = tr->buffer" should be better.
> >
> oh! sorry for my careless!
> >
> >> Signed-off-by: Zhenwen Xu <[email protected]>
> >> ---
> >> kernel/trace/trace_branch.c | 2 +-
> >> kernel/trace/trace_hw_branches.c | 2 +-
> >> 2 files changed, 2 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/kernel/trace/trace_branch.c b/kernel/trace/trace_branch.c
> >> index 7a7a9fd..216e2dd 100644
> >> --- a/kernel/trace/trace_branch.c
> >> +++ b/kernel/trace/trace_branch.c
> >> @@ -54,7 +54,7 @@ probe_likely_condition(struct ftrace_branch_data *f, int val, int expect)
> >> goto out;
> >>
> >> pc = preempt_count();
> >> - event = trace_buffer_lock_reserve(tr, TRACE_BRANCH,
> >> + event = trace_buffer_lock_reserve(tr->buffer, TRACE_BRANCH,
> >> sizeof(*entry), flags, pc);

Also, You should not pass in the buffer directly. This is because the
tr->buffer can change, and if it changes between the reserve and commit,
then you can corrupt the ring buffer.

What you want to do is:

struct ring_buffer *buffer = tr->buffer;

event = trace_buffer_lock_reserve(buffer, TRACE_BRANCH ...)

[...]

ring_buffer_unlock_commit(buffer, ...)


-- Steve

> >> if (!event)
> >> goto out;
> >> diff --git a/kernel/trace/trace_hw_branches.c b/kernel/trace/trace_hw_branches.c
> >> index 23b6385..1cc17ca 100644
> >> --- a/kernel/trace/trace_hw_branches.c
> >> +++ b/kernel/trace/trace_hw_branches.c
> >> @@ -180,7 +180,7 @@ void trace_hw_branch(u64 from, u64 to)
> >> if (atomic_inc_return(&tr->data[cpu]->disabled) != 1)
> >> goto out;
> >>
> >> - event = trace_buffer_lock_reserve(tr, TRACE_HW_BRANCHES,
> >> + event = trace_buffer_lock_reserve(tr->buffer, TRACE_HW_BRANCHES,
> >> sizeof(*entry), 0, 0);
> >> if (!event)
> >> goto out;
> >>
> >
> >
>
>