[PATCH 6.6 079/261] tracing/mmiotrace: Reset dropped_count in mmio_reset_data()

6.6-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Masami Hiramatsu (Google) <[email protected]>

[ Upstream commit c786d2bdf1f3964deee192ad942dee2a741c1e2c ]

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) <[email protected]>
Signed-off-by: Steven Rostedt <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
---
 kernel/trace/trace_mmiotrace.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/trace/trace_mmiotrace.c b/kernel/trace/trace_mmiotrace.c
index 4d9e5c830dbe1..c523ce5aa4958 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);
 }
-- 
2.53.0