[PATCH v1] ptp: ocp: fix NULL deref in _signal_summary_show

[Sagi Maimon]

Sysfs signal show operations can invoke _signal_summary_show before
signal_out array elements are initialized, causing a NULL pointer
dereference. Add NULL checks for signal_out elements to prevent kernel
crashes.

Fixes: b325af3cfab9 ("ptp: ocp: Add signal generators and update sysfs nodes")
Signed-off-by: Sagi Maimon <maimon.sagi@xxxxxxxxx>
---
 drivers/ptp/ptp_ocp.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/ptp/ptp_ocp.c b/drivers/ptp/ptp_ocp.c
index 7945c6be1f7c..4c7893539cec 100644
--- a/drivers/ptp/ptp_ocp.c
+++ b/drivers/ptp/ptp_ocp.c
@@ -3963,6 +3963,9 @@ _signal_summary_show(struct seq_file *s, struct ptp_ocp *bp, int nr)
 	bool on;
 	u32 val;
 
+	if (!bp->signal_out[nr])
+		return;
+
 	on = signal->running;
 	sprintf(label, "GEN%d", nr + 1);
 	seq_printf(s, "%7s: %s, period:%llu duty:%d%% phase:%llu pol:%d",
-- 
2.47.0