On Wed, Sep 13, 2017 at 05:18:56PM +0200, demerphq wrote: > > Hmph. That is very disturbing. But with that information I should be > > able to track down the culprit. Thanks for digging. > > FWIW, I see that git_config_set_multivar_in_file_gently() uses > write_in_full() which in turn uses xwrite(), but the latter has the > following comment on it: > > /* > * xwrite() is the same a write(), but it automatically restarts write() > * operations with a recoverable error (EAGAIN and EINTR). xwrite() DOES NOT > * GUARANTEE that "len" bytes is written even if the operation is successful. > */ > > I suspect that at this point I am not adding much value here, so I > will leave it at this. No, the problem is in this line: if (write_in_full(fd, contents + copy_begin, copy_end - copy_begin) < copy_end - copy_begin) goto write_err_out; write_in_full() returns -1 on error (_not_ how many bytes were actually written). So its return is a signed ssize_t. But the result of the pointer subtraction "copy_end - copy_begin" is an unsigned ptrdiff_t. The compiler promotes the signed to an unsigned, so the condition can never be true (the "-1" becomes the highest possible value). I have the fix, but I'm searching the code base for other instances of the same error. -Peff