[Bug 1027977]

[Moritz Hassert]

Yes, compiling myself was of course the quick solution. I patched and
built the valgrind package from Ubuntu locally and it works like a
charm. Thanks again! Saves me lots of trouble.

There's no particular reason to care about other Ubuntu users. It's not
really an security issue or anything like that. But I do care about
myself and all the machines I would have to install my custom deb
package.

I adapted your "Patch for VEX" patch for version 3.7.0. It's attached to my corresponding Ubuntu bug report:
https://bugs.launchpad.net/ubuntu/+source/valgrind/+bug/1027977

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to valgrind in Ubuntu.
https://bugs.launchpad.net/bugs/1027977

Title:
  strstr() function produces wrong results under valgrind callgrind

Status in Valgrind:
  Fix Released
Status in “valgrind” package in Ubuntu:
  Confirmed

Bug description:
  $valgrind --version
  valgrind-3.7.0

  When an application that uses the strstr() function from the C standard library is profiled with valgrind --tool=callgrind, the strstr() function produces false results (at least) under the following conditions:
  * the string s1 to search in and the string s2 to search for are exact duplicates, that is strcmp(s1,s2)==0. s1 and s2 don't need to be pointing to the same memory object.
  * the string length (excluding terminating zero) is a multiple of 16

  Expected result: strstr(s1,s2) returns s1, indicating a match at the first charactor of s1
  What happens: strstr(s1,s2) returns NULL, indicating no matching substring was found.

  See attached minimal testcase for an example. Reproduce under Ubuntu 12.04 with the following steps:
  $gcc strstrtest.c -o strstrtest
  $./ strstrtest    # <-- should report no errors
  $valgrind --tool=callgrind ./ strstrtest  # <-- should report errors for lengths multiple of 16

  - The Problem does not show up under valgrind-3.6.0.SVN-Debian from Ubuntu 10.04 Lucid Lynx
  - The Problem does not show up under tool=memcheck.

  Some more info:
  OS: Ubuntu 12.04 Precise Pangolin
  $uname -a
  Linux mhassert 3.2.0-26-generic #41-Ubuntu SMP Thu Jun 14 17:49:24 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux

To manage notifications about this bug go to:
https://bugs.launchpad.net/valgrind/+bug/1027977/+subscriptions