tools lib traceevent: Zero should not be considered "not found" in eval_flag() (7c27f78a) · Commits · 戴 / test

Guilherme Cox found that: There is, however, a potential bug if there is an item with code zero that is not the first one in the symbol list, since eval_flag(..) returns 0 when it doesn't find anything. That is, if you have the following enums: enum { FOO_START = 0, FOO_GO = 1, FOO_END = 2 } and then have: __print_symbolic(foo, FOO_GO, "go", FOO_START, "start", FOO_END, "end") If none of the enums are known to pevent, then eval_flag() will return zero, and it will match it to the first item in the list, which would be FOO_GO, which is not zero. Luckily, in most cases, the first element would be zero, and the parsing would match out of sheer luck. Reported-by:

Guilherme Cox <cox@computer.org> Signed-off-by:

Steven Rostedt <rostedt@goodmis.org> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Link: http://lkml.kernel.org/r/20150324145813.0bfe95ba@gandalf.local.home Signed-off-by:

Arnaldo Carvalho de Melo <acme@redhat.com>

tools/lib/traceevent/event-parse.c

+5 −5

Original line number	Diff line number	Diff line
		@@ -3615,7 +3615,7 @@ static const struct flag flags[] = {
		{ "HRTIMER_RESTART", 1 },
		};

		static unsigned long long eval_flag(const char *flag)
		static long long eval_flag(const char *flag)
		{
		int i;

		@@ -3631,7 +3631,7 @@ static unsigned long long eval_flag(const char *flag)
		if (strcmp(flags[i].name, flag) == 0)
		return flags[i].value;

		return 0;
		return -1LL;
		}

		static void print_str_to_seq(struct trace_seq s, const char format,
		@@ -3705,7 +3705,7 @@ static void print_str_arg(struct trace_seq s, void data, int size,
		struct print_flag_sym *flag;
		struct format_field *field;
		struct printk_map *printk;
		unsigned long long val, fval;
		long long val, fval;
		unsigned long addr;
		char *str;
		unsigned char *hex;
		@@ -3764,11 +3764,11 @@ static void print_str_arg(struct trace_seq s, void data, int size,
		print = 0;
		for (flag = arg->flags.flags; flag; flag = flag->next) {
		fval = eval_flag(flag->value);
		if (!val && !fval) {
		if (!val && fval < 0) {
		print_str_to_seq(s, format, len_arg, flag->str);
		break;
		}
		if (fval && (val & fval) == fval) {
		if (fval > 0 && (val & fval) == fval) {
		if (print && arg->flags.delim)
		trace_seq_puts(s, arg->flags.delim);
		print_str_to_seq(s, format, len_arg, flag->str);

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