[v5] ring-buffer/tracing: Allow ring buffer to have bigger sub buffers

[PATCH v5 06/15] ring-buffer: Clear pages on error in ring_buffer_subbuf_order_set() failure

Posted by Steven Rostedt 1 year, 12 months ago

From: "Steven Rostedt (Google)" <rostedt@goodmis.org>

On failure to allocate ring buffer pages, the pointer to the CPU buffer
pages is freed, but the pages that were allocated previously were not.
Make sure they are freed too.

Fixes: TBD ("tracing: Set new size of the ring buffer sub page")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 kernel/trace/ring_buffer.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index c2afcf98ea91..3c11e8e811ed 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -5927,6 +5927,7 @@ int ring_buffer_subbuf_order_set(struct trace_buffer *buffer, int order)
 	for_each_buffer_cpu(buffer, cpu) {
 		if (!cpu_buffers[cpu])
 			continue;
+		rb_free_cpu_buffer(cpu_buffers[cpu]);
 		kfree(cpu_buffers[cpu]);
 	}
 	kfree(cpu_buffers);
-- 
2.42.0

Re: [PATCH v5 06/15] ring-buffer: Clear pages on error in ring_buffer_subbuf_order_set() failure

Posted by Masami Hiramatsu (Google) 1 year, 12 months ago

On Tue, 19 Dec 2023 13:54:20 -0500
Steven Rostedt <rostedt@goodmis.org> wrote:

> From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
> 
> On failure to allocate ring buffer pages, the pointer to the CPU buffer
> pages is freed, but the pages that were allocated previously were not.
> Make sure they are freed too.
> 
> Fixes: TBD ("tracing: Set new size of the ring buffer sub page")

Do you merge this fix to the original one in the same series later?
I think it is better to merge it for git bisect.

Thank you,

> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
> ---
>  kernel/trace/ring_buffer.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
> index c2afcf98ea91..3c11e8e811ed 100644
> --- a/kernel/trace/ring_buffer.c
> +++ b/kernel/trace/ring_buffer.c
> @@ -5927,6 +5927,7 @@ int ring_buffer_subbuf_order_set(struct trace_buffer *buffer, int order)
>  	for_each_buffer_cpu(buffer, cpu) {
>  		if (!cpu_buffers[cpu])
>  			continue;
> +		rb_free_cpu_buffer(cpu_buffers[cpu]);
>  		kfree(cpu_buffers[cpu]);
>  	}
>  	kfree(cpu_buffers);
> -- 
> 2.42.0
> 
> 


-- 
Masami Hiramatsu (Google) <mhiramat@kernel.org>

Re: [PATCH v5 06/15] ring-buffer: Clear pages on error in ring_buffer_subbuf_order_set() failure

Posted by Steven Rostedt 1 year, 12 months ago

On Thu, 21 Dec 2023 01:23:14 +0900
Masami Hiramatsu (Google) <mhiramat@kernel.org> wrote:

> On Tue, 19 Dec 2023 13:54:20 -0500
> Steven Rostedt <rostedt@goodmis.org> wrote:
> 
> > From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
> > 
> > On failure to allocate ring buffer pages, the pointer to the CPU buffer
> > pages is freed, but the pages that were allocated previously were not.
> > Make sure they are freed too.
> > 
> > Fixes: TBD ("tracing: Set new size of the ring buffer sub page")  
> 
> Do you merge this fix to the original one in the same series later?
> I think it is better to merge it for git bisect.

It only fixes the new functionality. If a git bisect gets here for that,
then we know the issue already. But it shouldn't break bisect for things
that happened before this change.

The reason I'm not merging this with the other patch is because the
original patch is from Tzvetomir, who isn't working on this anymore. I want
to keep his patches untouched, and anything I do is on top of it.

-- Steve