6.6-stable review patch. If anyone has any objections, please let me know.
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From: Steven Rostedt (Google) rostedt@goodmis.org
commit d06aff1cb13d2a0d52b48e605462518149c98c81 upstream.
The snapshot buffer is to mimic the main buffer so that when a snapshot is needed, the snapshot and main buffer are swapped. When the snapshot buffer is allocated, it is set to the minimal size that the ring buffer may be at and still functional. When it is allocated it becomes the same size as the main ring buffer, and when the main ring buffer changes in size, it should do.
Currently, the resize only updates the snapshot buffer if it's used by the current tracer (ie. the preemptirqsoff tracer). But it needs to be updated anytime it is allocated.
When changing the size of the main buffer, instead of looking to see if the current tracer is utilizing the snapshot buffer, just check if it is allocated to know if it should be updated or not.
Also fix typo in comment just above the code change.
Link: https://lore.kernel.org/linux-trace-kernel/20231210225447.48476a6a@rorschach...
Cc: stable@vger.kernel.org Cc: Mark Rutland mark.rutland@arm.com Cc: Mathieu Desnoyers mathieu.desnoyers@efficios.com Fixes: ad909e21bbe69 ("tracing: Add internal tracing_snapshot() functions") Reviewed-by: Masami Hiramatsu (Google) mhiramat@kernel.org Signed-off-by: Steven Rostedt (Google) rostedt@goodmis.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- kernel/trace/trace.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -6352,7 +6352,7 @@ static int __tracing_resize_ring_buffer( if (!tr->array_buffer.buffer) return 0;
- /* Do not allow tracing while resizng ring buffer */ + /* Do not allow tracing while resizing ring buffer */ tracing_stop_tr(tr);
ret = ring_buffer_resize(tr->array_buffer.buffer, size, cpu); @@ -6360,7 +6360,7 @@ static int __tracing_resize_ring_buffer( goto out_start;
#ifdef CONFIG_TRACER_MAX_TRACE - if (!tr->current_trace->use_max_tr) + if (!tr->allocated_snapshot) goto out;
ret = ring_buffer_resize(tr->max_buffer.buffer, size, cpu);