From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Date: Tue, 28 Jul 2026 12:49:51 +0000 (+0900)
Subject: tracing/mmiotrace: Reset dropped_count in mmio_reset_data()
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c786d2bdf1f3964deee192ad942dee2a741c1e2c;p=thirdparty%2Flinux.git

tracing/mmiotrace: Reset dropped_count in mmio_reset_data()

mmio_reset_data() is called during tracer initialization, reset, and
start. While it resets overrun_detected and prev_overruns, it neglects
to reset dropped_count. Consequently, dropped event counts from prior
tracing sessions persist in dropped_count and corrupt overrun reports
in subsequent runs.

Fix this by explicitly calling atomic_set(&dropped_count, 0) in
mmio_reset_data().

Link: https://patch.msgid.link/178524299122.56416.16277704230639425172.stgit@devnote2
Fixes: 173ed24ee2d6 ("mmiotrace: count events lost due to not recording")
Assisted-by: Antigravity:gemini-3.6-flash
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---

diff --git a/kernel/trace/trace_mmiotrace.c b/kernel/trace/trace_mmiotrace.c
index b88b8d9923ad..e064ba3f28cb 100644
--- a/kernel/trace/trace_mmiotrace.c
+++ b/kernel/trace/trace_mmiotrace.c
@@ -29,6 +29,7 @@ static void mmio_reset_data(struct trace_array *tr)
 {
 	overrun_detected = false;
 	prev_overruns = 0;
+	atomic_set(&dropped_count, 0);
 
 	tracing_reset_online_cpus(&tr->array_buffer);
 }