From: Namhyung Kim <namhyung@xxxxxxxxxx> 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) Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx> Acked-by: Steven Rostedt <rostedt@xxxxxxxxxxx> Cc: David Ahern <dsahern@xxxxxxxxx> Cc: Jiri Olsa <jolsa@xxxxxxxxxx> Cc: Joonsoo Kim <js1304@xxxxxxxxx> Cc: Minchan Kim <minchan@xxxxxxxxxx> Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> Cc: linux-mm@xxxxxxxxx Link: http://lkml.kernel.org/r/1428298576-9785-10-git-send-email-namhyung@xxxxxxxxxx [ Replaced 'swap' with 'rotate' in a comment as requested by Steve and agreed by Namhyung ] Signed-off-by: Arnaldo Carvalho de Melo <acme@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..12a7e2a40c89 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; + + /* rotate 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) { -- 1.9.3 -- 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>