tracing: Stop current tracer when resizing buffer
authorSteven Rostedt (Google) <rostedt@goodmis.org>
Tue, 5 Dec 2023 21:52:10 +0000 (16:52 -0500)
committerSteven Rostedt (Google) <rostedt@goodmis.org>
Tue, 5 Dec 2023 22:06:12 +0000 (17:06 -0500)
commitd78ab792705c7be1b91243b2544d1a79406a2ad7
tree97ffb49b0c906e3636e416e2eab2e2c10a5e0c47
parent7be76461f302ec05cbd62b90b2a05c64299ca01f
tracing: Stop current tracer when resizing buffer

When the ring buffer is being resized, it can cause side effects to the
running tracer. For instance, there's a race with irqsoff tracer that
swaps individual per cpu buffers between the main buffer and the snapshot
buffer. The resize operation modifies the main buffer and then the
snapshot buffer. If a swap happens in between those two operations it will
break the tracer.

Simply stop the running tracer before resizing the buffers and enable it
again when finished.

Link: https://lkml.kernel.org/r/20231205220010.748996423@goodmis.org
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Fixes: 3928a8a2d9808 ("ftrace: make work with new ring buffer")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
kernel/trace/trace.c