[PATCH 08/25] coresight: perf: Validate context before resuming trace
From: Leo Yan <leo.yan@arm.com>
Date: 2026-09-15 15:49:52
Also in:
linux-doc, linux-perf-users, lkml
Subsystem:
arm/coresight framework and drivers, hardware tracing facilities, the rest · Maintainers:
Suzuki K Poulose, Alexander Shishkin, Linus Torvalds
An AUX pause ends the current AUX output before trying to begin a new one. That new beginning can fail, leaving the CoreSight path published after the perf handle has become inactive. AUX resume may also overlap a normal stop which clears the per-CPU context. Pass the per-CPU ETM context to etm_event_resume() and centralize both lifetime checks there. Use perf_get_aux() to confirm that the AUX output handle is active and path to confirm that the context is still live. Resume the source only when both checks succeed. Assisted-by: Codex:gpt-6 Signed-off-by: Leo Yan <leo.yan@arm.com> --- drivers/hwtracing/coresight/coresight-etm-perf.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c
index c7454da5c881c4a8eea5cc77902c9113c297096e..e3c9d3cf84c502f357a430bc3bfa854a776618f1 100644
--- a/drivers/hwtracing/coresight/coresight-etm-perf.c
+++ b/drivers/hwtracing/coresight/coresight-etm-perf.c@@ -517,11 +517,17 @@ static void *etm_setup_aux(struct perf_event *event, void **pages, goto out; } -static int etm_event_resume(struct coresight_path *path) +static int etm_event_resume(struct etm_ctxt *ctxt) { + struct perf_output_handle *handle = &ctxt->handle; struct coresight_device *source; + struct coresight_path *path; int ret; + if (!perf_get_aux(handle)) + return 0; + + path = etm_event_get_ctxt_path(ctxt); if (!path) return 0;
@@ -547,8 +553,7 @@ static void etm_event_start(struct perf_event *event, int flags) u64 hw_id; if (flags & PERF_EF_RESUME) { - path = etm_event_get_ctxt_path(ctxt); - if (etm_event_resume(path) < 0) + if (etm_event_resume(ctxt) < 0) goto fail; return; }
--
2.34.1