Currently it ignores operator priority and just sets processed args as a
right operand. But it could result in priority inversion in case that
the right operand is also a operator arg and its priority is lower.
For example, following print format is from new kmem events.
"page=%p", REC->pfn != -1UL ? (((struct page *)(0xffffea0000000000UL)) + (REC->pfn)) : ((void *)0)
But this was treated as below:
REC->pfn != ((null - 1UL) ? ((struct page *)0xffffea0000000000UL + REC->pfn) : (void *) 0)
In this case, the right arg was '?' operator which has lower priority.
But it just sets the whole arg so making the output confusing - page was
always 0 or 1 since that's the result of logical operation.
With this patch, it can handle it properly like following:
((REC->pfn != (null - 1UL)) ? ((struct page *)0xffffea0000000000UL + REC->pfn) : (void *) 0)
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
---
tools/lib/traceevent/event-parse.c | 17 ++++++++++++++++-
1 file changed, 16 insertions(+), 1 deletion(-)
diff --git a/tools/lib/traceevent/event-parse.c b/tools/lib/traceevent/event-parse.c
index 6d31b6419d37..604bea5c3fb0 100644
--- a/tools/lib/traceevent/event-parse.c
+++ b/tools/lib/traceevent/event-parse.c
@@ -1939,7 +1939,22 @@ process_op(struct event_format *event, struct print_arg *arg, char **tok)
goto out_warn_free;
type = process_arg_token(event, right, tok, type);
- arg->op.right = right;
+
+ if (right->type == PRINT_OP &&
+ get_op_prio(arg->op.op) < get_op_prio(right->op.op)) {
+ struct print_arg tmp;
+
+ /* swap ops according to the priority */
+ arg->op.right = right->op.left;
+
+ tmp = *arg;
+ *arg = *right;
+ *right = tmp;
+
+ arg->op.left = right;
+ } else {
+ arg->op.right = right;
+ }
} else if (strcmp(token, "[") == 0) {
--
2.3.2
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>