From: Steven Rostedt <rost...@goodmis.org> The mapping of the ring buffer to memory allocated at boot up will also expose a "last_boot_info" to help tooling to read the raw data from the last boot. As instances that have their ring buffer mapped to fixed memory cannot perform snapshots, they can either have the "snapshot" file or the "last_boot_info" file, but not both.
The code that added the "last_boot_info" file failed to notice that the "snapshot" creation was inside a "#ifdef CONFIG_TRACER_SNAPSHOT" and incorrectly placed the creation of the "last_boot_info" file within the ifdef block. Not only does it cause a warning when CONFIG_TRACER_SNAPSHOT is not enabled, it also incorrectly prevents the file from appearing. Link: https://lore.kernel.org/all/20240719102640.718554-1-a...@kernel.org/ Reported-by: Arnd Bergmann <a...@kernel.org> Fixes: 7a1d1e4b9639 ("tracing/ring-buffer: Add last_boot_info file to boot instance") Signed-off-by: Steven Rostedt (Google) <rost...@goodmis.org> --- kernel/trace/trace.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 5462fb10ff64..0d1841b3363e 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -9828,15 +9828,15 @@ init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer) if (ftrace_create_function_files(tr, d_tracer)) MEM_FAIL(1, "Could not allocate function filter files"); -#ifdef CONFIG_TRACER_SNAPSHOT if (tr->range_addr_start) { trace_create_file("last_boot_info", TRACE_MODE_READ, d_tracer, tr, &last_boot_fops); +#ifdef CONFIG_TRACER_SNAPSHOT } else { trace_create_file("snapshot", TRACE_MODE_WRITE, d_tracer, tr, &snapshot_fops); - } #endif + } trace_create_file("error_log", TRACE_MODE_WRITE, d_tracer, tr, &tracing_err_log_fops); -- 2.43.0
