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| author | Steven Rostedt (Google) <rostedt@goodmis.org> | 2023-04-04 22:21:15 -0400 |
|---|---|---|
| committer | Steven Rostedt (Google) <rostedt@goodmis.org> | 2023-04-04 22:29:53 -0400 |
| commit | e94891641c21f607e4d6887bcd3beff882fcc483 (patch) | |
| tree | e57d9f77fc0efab94415779934da9f5390c212dd | |
| parent | 9d52727f8043cfda241ae96896628d92fa9c50bb (diff) | |
| download | nvme-e94891641c21f607e4d6887bcd3beff882fcc483.tar.gz | |
tracing: Fix ftrace_boot_snapshot command line logic
The kernel command line ftrace_boot_snapshot by itself is supposed to
trigger a snapshot at the end of boot up of the main top level trace
buffer. A ftrace_boot_snapshot=foo will do the same for an instance called
foo that was created by trace_instance=foo,...
The logic was broken where if ftrace_boot_snapshot was by itself, it would
trigger a snapshot for all instances that had tracing enabled, regardless
if it asked for a snapshot or not.
When a snapshot is requested for a buffer, the buffer's
tr->allocated_snapshot is set to true. Use that to know if a trace buffer
wants a snapshot at boot up or not.
Since the top level buffer is part of the ftrace_trace_arrays list,
there's no reason to treat it differently than the other buffers. Just
iterate the list if ftrace_boot_snapshot was specified.
Link: https://lkml.kernel.org/r/20230405022341.895334039@goodmis.org
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ross Zwisler <zwisler@google.com>
Fixes: 9c1c251d670bc ("tracing: Allow boot instances to have snapshot buffers")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
| -rw-r--r-- | kernel/trace/trace.c | 13 |
1 files changed, 7 insertions, 6 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index ed1d1093f5e9d..4686473b8497b 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -10393,19 +10393,20 @@ out: void __init ftrace_boot_snapshot(void) { +#ifdef CONFIG_TRACER_MAX_TRACE struct trace_array *tr; - if (snapshot_at_boot) { - tracing_snapshot(); - internal_trace_puts("** Boot snapshot taken **\n"); - } + if (!snapshot_at_boot) + return; list_for_each_entry(tr, &ftrace_trace_arrays, list) { - if (tr == &global_trace) + if (!tr->allocated_snapshot) continue; - trace_array_puts(tr, "** Boot snapshot taken **\n"); + tracing_snapshot_instance(tr); + trace_array_puts(tr, "** Boot snapshot taken **\n"); } +#endif } void __init early_trace_init(void) |