[for-linus][PATCH 1/5] ring-buffer: Unlock resize on mmap error

[Steven Rostedt]

From: Steven Rostedt <rostedt@xxxxxxxxxxx>

Memory mapping the tracing ring buffer will disable resizing the buffer.
But if there's an error in the memory mapping like an invalid parameter,
the function exits out without re-enabling the resizing of the ring
buffer, preventing the ring buffer from being resized after that.

Cc: stable@xxxxxxxxxxxxxxx
Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Cc: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx>
Cc: Vincent Donnefort <vdonnefort@xxxxxxxxxx>
Link: https://lore.kernel.org/20250213131957.530ec3c5@xxxxxxxxxxxxxxxxxx
Fixes: 117c39200d9d7 ("ring-buffer: Introducing ring-buffer mapping functions")
Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
---
 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 b8e0ae15ca5b..07b421115692 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -7126,6 +7126,7 @@ int ring_buffer_map(struct trace_buffer *buffer, int cpu,
 		kfree(cpu_buffer->subbuf_ids);
 		cpu_buffer->subbuf_ids = NULL;
 		rb_free_meta_page(cpu_buffer);
+		atomic_dec(&cpu_buffer->resize_disabled);
 	}
 
 unlock:
-- 
2.47.2