The perf_output_sample_ustack in kernel/events/core.c only writes a
single 64 bit word
if it can't dump the user registers. From the current version of the
man page, I would
have expected two 64 bit words (one for size, one for dyn_size). Change the man
page to make this behavior explicit.
This is my first man-pages patch, please let me know if I should do
anything else.
---
man2/perf_event_open.2 | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/man2/perf_event_open.2 b/man2/perf_event_open.2
index 0e42c50..6788154 100644
--- a/man2/perf_event_open.2
+++ b/man2/perf_event_open.2
@@ -1994,7 +1994,7 @@ struct {
/* if PERF_SAMPLE_REGS_USER */
u64 size; /* if PERF_SAMPLE_STACK_USER */
char data[size]; /* if PERF_SAMPLE_STACK_USER */
- u64 dyn_size; /* if PERF_SAMPLE_STACK_USER */
+ u64 dyn_size; /* if PERF_SAMPLE_STACK_USER && size != 0 */
u64 weight; /* if PERF_SAMPLE_WEIGHT */
u64 data_src; /* if PERF_SAMPLE_DATA_SRC */
u64 transaction;/* if PERF_SAMPLE_TRANSACTION */
@@ -2185,6 +2185,11 @@ stack pointer at the time of sampling).
.I dyn_size
is the amount of data actually dumped (can be less than
.IR size ).
+Note that
+.I dyn_size
+is omitted if
+.I size
+is 0.
.TP
.I weight
If
--
2.6.4
--
To unsubscribe from this list: send the line "unsubscribe linux-man" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
