2023-05-03 14:13:33

by Ondrej Mosnacek

Subject: [PATCH] tracing: Fix permissions for the buffer_percent file

This file defines both read and write operations, yet it is being
created as read-only. This means that it can't be written to without the
CAP_DAC_OVERRIDE capability. Fix the permissions to allow root to write
to it without the need to override DAC perms.

Fixes: 03329f993978 ("tracing: Add tracefs file buffer_percentage")
Signed-off-by: Ondrej Mosnacek <[email protected]>
---
kernel/trace/trace.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 45551c7b4c365..e278f4202a7ed 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -9655,7 +9655,7 @@ init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer)

tr->buffer_percent = 50;

- trace_create_file("buffer_percent", TRACE_MODE_READ, d_tracer,
+ trace_create_file("buffer_percent", TRACE_MODE_WRITE, d_tracer,
tr, &buffer_percent_fops);

create_trace_options_dir(tr);
--
2.40.1

2023-05-03 17:04:13

by Steven Rostedt

Subject: Re: [PATCH] tracing: Fix permissions for the buffer_percent file

On Wed, 3 May 2023 16:01:14 +0200
Ondrej Mosnacek <[email protected]> wrote:

> This file defines both read and write operations, yet it is being
> created as read-only. This means that it can't be written to without the
> CAP_DAC_OVERRIDE capability. Fix the permissions to allow root to write
> to it without the need to override DAC perms.
>
> Fixes: 03329f993978 ("tracing: Add tracefs file buffer_percentage")
> Signed-off-by: Ondrej Mosnacek <[email protected]>

Applied. Thanks Ondrej!

-- Steve