[Bug libc/5058] New: libintl "dgettext" is not thread safe.

["madcoder at debian dot org" <sourceware-bugzilla at sourceware dot org>]

in debian bug http://bugs.debian.org/443660 was reported a crash due to 
dgettext in a multi-threaded context.

It was reported that when it crashes (as it seems to be a race, it's hard to) 
a valgrind trace looks like that:

==3535== Thread 3:
==3535== Invalid read of size 4
==3535==    at 0x4063F0B: _nl_find_msg (dcigettext.c:862)
==3535==    by 0x4064A41: __dcigettext (dcigettext.c:639)
==3535==    by 0x4063972: dcgettext (dcgettext.c:53)
==3535==    by 0x406399F: dgettext (dgettext.c:54)
==3535==    by 0x80484DD: run (in /home/remi/a.out)
==3535==    by 0x402D2D2: start_thread (pthread_create.c:296)
==3535==    by 0x41124ED: clone (in /usr/lib/debug/libc-2.6.1.so)
==3535==  Address 0x418C91C is 0 bytes after a block of size 12 alloc'd
==3535==    at 0x4024862: realloc (vg_replace_malloc.c:306)
==3535==    by 0x4063FF1: _nl_find_msg (dcigettext.c:876)
==3535==    by 0x4064A41: __dcigettext (dcigettext.c:639)
==3535==    by 0x4063972: dcgettext (dcgettext.c:53)
==3535==    by 0x406399F: dgettext (dgettext.c:54)
==3535==    by 0x80484DD: run (in /home/remi/a.out)
==3535==    by 0x402D2D2: start_thread (pthread_create.c:296)
==3535==    by 0x41124ED: clone (in /usr/lib/debug/libc-2.6.1.so)


THe second block looks indeed fishy, as I seem to understand that the realloc 
is perfomed on a shared data, without locking.

-- 
           Summary: libintl "dgettext" is not thread safe.
           Product: glibc
           Version: unspecified
            Status: NEW
          Severity: normal
          Priority: P2
         Component: libc
        AssignedTo: drepper at redhat dot com
        ReportedBy: madcoder at debian dot org
                CC: debian-glibc at lists dot debian dot org,glibc-bugs at
                    sources dot redhat dot com


http://sourceware.org/bugzilla/show_bug.cgi?id=5058

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