Re: "Switch !O_CREAT case to use of do_last()" causes segfault in glibc

[Al Viro <viro@ZenIV.linux.org.uk>]

On Sat, Mar 06, 2010 at 05:59:18PM +0000, Al Viro wrote:
> On Sat, Mar 06, 2010 at 09:43:42AM -0800, walt wrote:
> > Hi Al,
> > commit 1f36f774b22a0ceb7dd33eca626746c81a97b6a5
> > Author: Al Viro <viro@zeniv.linux.org.uk>
> > Date:   Sat Dec 26 10:56:19 2009 -0500
> > 
> >     Switch !O_CREAT case to use of do_last()
> > 
> >     ... and now we have all intents crap well localized
> > 
> > This commit is triggering a segfault when I try to open a spreadsheet in
> > openoffice:
> > 
> > Program received signal SIGSEGV, Segmentation fault.
> > 0x00007ffff6d13129 in __readdir (dirp=0x0) at ../sysdeps/unix/readdir.c:45
> > 45      ../sysdeps/unix/readdir.c: No such file or directory.
> >         in ../sysdeps/unix/readdir.c
> > (gdb) bt
> > #0  0x00007ffff6d13129 in __readdir (dirp=0x0) at ../sysdeps/unix/readdir.c:45
> > #1  0x00007ffff1dc58b0 in ?? () from /usr/lib/libicuuc.so.42
> > #2  0x00007ffff1dc591d in ?? () from /usr/lib/libicuuc.so.42
> > #3  0x00007ffff1dc5d7e in uprv_tzname_4_2 () from /usr/lib/libicuuc.so.42
> > #4  0x00007fffd7f73601 in icu_4_2::TimeZone::initDefault() () from /usr/lib/libicui18n.so.42
> > #5  0x00007fffd7f738c5 in icu_4_2::TimeZone::createDefault() () from /usr/lib/libicui18n.so.42
> > #6  0x00007fffd7f6e5c9 in icu_4_2::Calendar::createInstance(icu_4_2::Locale const&, UErrorCode&) ()
> >    from /usr/lib/libicui18n.so.42
> 
> Very interesting.  Could you give the relevant parts of strace (or reproduce
> it with something less monumental than openoffice)?

_Really_ interesting; it doesn't look like an oops - smells like an attempt
to do opendir() that fails for some reason, goes unnoticed and resulting
FILE * (i.e. NULL) is fed to readdir()?

What does it attempt to open?