On Tuesday, August 4, 2020 2:10:46 AM CEST Bruno Haible wrote: > Kamil Dudka wrote: > > Yes, the `ASSERT (msg3 == msg4 || STREQ (msg3, str3))` check is failing here: > > https://git.savannah.gnu.org/gitweb/?p=gnulib.git;a=blob;f=tests/test-> > > > strerror_r.c;h=b11d6fd9#l170 > The ASSERT means "either msg3 has been clobbered by the strerror (1729576) > call, or it has been left unmodified". If it fails, something is happening > that we don't understand.
I know what the ASSERT means. But the documentation of strerror() does not say that such an assertion is always satisfied, does it? > Can you, in an interactive gdb session, set a hardware watchpoint on the > value of msg3? I was not able to allocate the appropriate HW when I was debugging the issue two weeks ago. They key question is: Does any SW we care about rely on the undocumented assumption that calls to strerror() modify previously returned strings only by overwriting them with the last returned string? > One of these lines must modify its contents. The question is: where? > > msg4 = strerror (1729576); I believe it is this ^^^ line. Kamil > ASSERT (msg4); > str4 = strdup (msg4); > ASSERT (str4); > > strerror_r (EACCES, buf, sizeof buf); > strerror_r (-5, buf, sizeof buf); > > Bruno
