On Mon, 04 Feb 2013 08:48:57 +0100 Markus Armbruster <[email protected]> wrote:
> [Note cc: Luiz] > > Peter Maydell <[email protected]> writes: > > > On 2 February 2013 21:37, Andreas Färber <[email protected]> wrote: > >> Am 02.02.2013 22:19, schrieb Peter Maydell: > >>> It's OK and expected for visitors to return errors when presented with > >>> the fuzz test's random data. This means the test harness needs to > >>> handle them; check for and free any error after each visitor call, > >>> and only free the string returned by visit_type_str if visit_type_str > >>> succeeded. > >>> > >>> This fixes a problem where this test failed the MacOSX malloc() > >>> consistency checks and might segfault on other platforms [due > >>> to calling free() on an uninitialized pointer variable]. > >>> > >>> Signed-off-by: Peter Maydell <[email protected]> > >>> --- > >>> tests/test-string-input-visitor.c | 23 ++++++++++++++++++++++- > >>> 1 file changed, 22 insertions(+), 1 deletion(-) > >>> > >>> diff --git a/tests/test-string-input-visitor.c > >>> b/tests/test-string-input-visitor.c > >>> index f6b0093..793b334 100644 > >>> --- a/tests/test-string-input-visitor.c > >>> +++ b/tests/test-string-input-visitor.c > >>> @@ -194,20 +194,41 @@ static void > >>> test_visitor_in_fuzz(TestInputVisitorData *data, > >>> > >>> v = visitor_input_test_init(data, buf); > >>> visit_type_int(v, &ires, NULL, &errp); > >>> + if (error_is_set(&errp)) { > >>> + error_free(errp); > >>> + errp = NULL; > >>> + } > >> > >> It seems to me the naming is bad here: errp appears to be an Error*, not > >> an Error**. It would be nice to fix this within the function touched. > > > > "Error *errp" is blessed by docs/writing-qmp-commands.txt (and > > git grep 'Error \*errp' has 80 examples in the tree). I think > > if I were writing this code I'd probably agree with you about the > > naming, but I'm not and I don't particularly feel like changing > > names somebody else has been consistent about in this source file > > in the course of fixing a bug. > > > >> Since it is an Error*, I think it was said that we should not use > >> error_is_set() but err != NULL (or if you prefer, just err). > >> error_is_set() is intended for **errp arguments that may be NULL. > > > > Calling error_is_set(&some_local_err_ptr) is also in the > > examples in the docs. If not doing that is the recommendation > > there should be a doc comment in error.h about that. > > I'd find this clearer: > > v = visitor_input_test_init(data, buf); > visit_type_int(v, &ires, NULL, &errp); > error_free(errp); > errp = NULL; > > Makes it blatantly obvious that the error is freed and the pointer reset > no matter what. It's simpler to get the error ignored by passing errp=NULL instead: visit_type_int(v, &ires, NULL, NULL); For the string test, you can do: sres = NULL; visit_type_str(v, &sres, NULL, NULL); g_free(sres); Two additional comments: o Isn't test_visitor_in_fuzz() leaking the visitors it allocates with visitor_input_test_init()? o This is probably the reason for the crash I reported here: http://lists.gnu.org/archive/html/qemu-devel/2013-01/msg05227.html
