ctime() was updated in 0.9.31 to call localtime_r() instead of localtime() to avoid using a static buffer. Unfortunately, this change replaces the static buffer (which is zeroed out on initialization) with an uninitialized local buffer.

In the common case, this has no effect. However, with a sufficiently large time_t value, the value returned differs from that returned by asctime(localtime(t)), and thus violates the ANSI/ISO standard.

An example input is (on a 64-bit machine):
time_t t = 0x7ffffffffff6c600;

When passed to uClibc 0.9.30.3, the resulting string is:
"Sun Jan  0 15:32:16 1900"

When passed to uClibc 0.9.31, the resulting string is:
"??? ??? ?? 15:32:16 ????"

The recommended fix is to zero-out the 'tm' struct using memset() before calling localtime_r.