While debugging another issue i noticed that the stack trace contains
one invalid entry at the end:
<idle>-0 [008] d..4. 26.484201: wake_lat: pid=0 delta=2629976084 000000009cc24024 stack=STACK:
=> __schedule+0xac6/0x1a98
=> schedule+0x126/0x2c0
=> schedule_timeout+0x150/0x2c0
=> kcompactd+0x9ca/0xc20
=> kthread+0x2f6/0x3d8
=> __ret_from_fork+0x8a/0xe8
=> 0x6b6b6b6b6b6b6b6b
This is because the code failed to add the one element containing the
number of entries to field_size.
Fixes: 00cf3d672a9d ("tracing: Allow synthetic events to pass around stacktraces")
Signed-off-by: Sven Schnelle <svens@xxxxxxxxxxxxx>
---
kernel/trace/trace_events_synth.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/kernel/trace/trace_events_synth.c b/kernel/trace/trace_events_synth.c
index 80a2a832f857..9897d0bfcab7 100644
--- a/kernel/trace/trace_events_synth.c
+++ b/kernel/trace/trace_events_synth.c
@@ -528,7 +528,8 @@ static notrace void trace_event_raw_event_synth(void *__data,
str_val = (char *)(long)var_ref_vals[val_idx];
if (event->dynamic_fields[i]->is_stack) {
- len = *((unsigned long *)str_val);
+ /* reserve one extra element for size */
+ len = *((unsigned long *)str_val) + 1;
len *= sizeof(unsigned long);
} else {
len = fetch_store_strlen((unsigned long)str_val);
--
2.39.2
