[Bug libc/4306] New: Valgrind complains about uninitialized bytes when calling timer_create()

[Bug libc/4306] New: Valgrind complains about uninitialized bytes when calling timer_create()

[bart dot vanassche at gmail dot com]

According to Valgrind some of the fields in the sigevent structure passed by
glibc to the timer_create() system call are uninitialized. Tested with glibc
built from CVS sources (2007-04-01). See also
http://bugs.kde.org/show_bug.cgi?id=124478 for the opinion of the Valgrind
authors about this issue.

$ uname -a
Linux pc-101 2.6.18.6 #8 Sun Feb 4 11:17:43 CET 2007 i686 athlon i386 GNU/Linux
$ /lib/libc.so.6
GNU C Library stable release version 2.5 (20061011), by Roland McGrath et al.
Copyright (C) 2006 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.
There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A
PARTICULAR PURPOSE.
Configured for i686-suse-linux.
Compiled by GNU CC version 4.1.2 20061115 (prerelease) (SUSE Linux).
Compiled on a Linux 2.6.18 system on 2006-11-26.
Available extensions:
        crypt add-on version 2.1 by Michael Glad and others
        GNU Libidn by Simon Josefsson
        GNU libio by Per Bothner
        NIS(YP)/NIS+ NSS modules 0.19 by Thorsten Kukuk
        NoVersion patch for broken glibc 2.0 binaries
        Native POSIX Threads Library by Ulrich Drepper et al
        BIND-8.2.3-T5B
Thread-local storage support included.
For bug reporting instructions, please see:
<http://www.gnu.org/software/libc/bugs.html>.
$ valgrind ./glibc-cvs-timer_create
==5995== Memcheck, a memory error detector.
==5995== Copyright (C) 2002-2007, and GNU GPL'd, by Julian Seward et al.
==5995== Using LibVEX rev 1734, a library for dynamic binary translation.
==5995== Copyright (C) 2004-2007, and GNU GPL'd, by OpenWorks LLP.
==5995== Using valgrind-3.3.0.SVN, a dynamic binary instrumentation framework.
==5995== Copyright (C) 2000-2007, and GNU GPL'd, by Julian Seward et al.
==5995== For more details, rerun with: -v
==5995==
==5995== Syscall param timer_create(evp) points to uninitialised byte(s)
==5995==    at 0x405F749: timer_create (in /lib/librt-2.5.so)
==5995==    by 0x80485E5: main (timer_create.c:23)
==5995==  Address 0xbef6ebf8 is on thread 1's stack
timer
timer
timer
timer
timer
==5995==
==5995== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 5 from 1)
==5995== malloc/free: in use at exit: 136 bytes in 1 blocks.
==5995== malloc/free: 8 allocs, 7 frees, 364 bytes allocated.
==5995== For counts of detected errors, rerun with: -v
==5995== searching for pointers to 1 not-freed blocks.
==5995== checked 98,532 bytes.
==5995==
==5995== LEAK SUMMARY:
==5995==    definitely lost: 0 bytes in 0 blocks.
==5995==      possibly lost: 136 bytes in 1 blocks.
==5995==    still reachable: 0 bytes in 0 blocks.
==5995==         suppressed: 0 bytes in 0 blocks.
==5995== Rerun with --leak-check=full to see details of leaked memory.

-- 
           Summary: Valgrind complains about uninitialized bytes when
                    calling timer_create()
           Product: glibc
           Version: unspecified
            Status: NEW
          Severity: normal
          Priority: P2
         Component: libc
        AssignedTo: drepper at redhat dot com
        ReportedBy: bart dot vanassche at gmail dot com
                CC: glibc-bugs at sources dot redhat dot com
 GCC build triplet: i686-suse-linux-gnu
  GCC host triplet: i686-suse-linux-gnu
GCC target triplet: i686-suse-linux-gnu


http://sourceware.org/bugzilla/show_bug.cgi?id=4306

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[Bug libc/4306] Valgrind complains about uninitialized bytes when calling timer_create()

[bart dot vanassche at gmail dot com]

------- Additional Comments From bart dot vanassche at gmail dot com  2007-04-01 16:25 -------
Created an attachment (id=1661)
 --> (http://sourceware.org/bugzilla/attachment.cgi?id=1661&action=view)
Source code of test program.


-- 


http://sourceware.org/bugzilla/show_bug.cgi?id=4306

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[Bug libc/4306] Valgrind complains about uninitialized bytes when calling timer_create()

[drepper at redhat dot com]

------- Additional Comments From drepper at redhat dot com  2007-04-28 05:04 -------
There is nothing wrong, valgrind does just not look deep enough into the
structure.  Otherwise it would have found that those bytes aren't used in this
call.  Since I don't expect valgrind to be fixed I've made some changes.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED


http://sourceware.org/bugzilla/show_bug.cgi?id=4306

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