Hi Steve, On Mon, Apr 06, 2015 at 10:45:04AM -0400, Steven Rostedt wrote: > On Mon, 6 Apr 2015 14:36:16 +0900 > Namhyung Kim <[email protected]> wrote: > > > 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) > > Nice catch. One nit. > > > > > Cc: Steven Rostedt <[email protected]> > > Signed-off-by: Namhyung Kim <[email protected]> > > --- > > 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 */ > > This isn't really a swap. Better term to use is "rotate".
You're right! > > But other than that, > > Acked-by: Steven Rostedt <[email protected]> Thanks for the review Namhyung > > > + 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) { > > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to [email protected] > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
