[PATCHES][BUG 13170] Fix crash in pthreadpool thread after failure from pthread_create

[Christof Schmitt]

On Wed, Dec 06, 2017 at 06:19:04PM +0100, Volker Lendecke wrote:
> On Tue, Dec 05, 2017 at 04:23:18PM -0700, Christof Schmitt via samba-technical wrote:
> > Another small update. I forgot to clear the inject variable at the end
> > of the test. That is not relevant for the test added here, but it causes
> > problems when adding more tests after that.
> 
> Patches look good. RB+ on the first two ones. Regarding the test: Yes,
> it's nasty, but do all linkers support the --wrap option? Do we have
> to #ifdef this depending on a configure check? If we can't get a
> resolution on this in soon, I'd vote to put in the bugfix without the
> test with the promise to actually work on the test. I know, famous
> last words, but this is important enough to not be held back by a
> cmocka vs linker flag discussion.

Andreas, please correct me in case i am missing something here:

My understanding is that intercepting the function calls in cmocka
relies on the linker wrap. That is pointed out in the lwn article and
can also be seen in the example provided by cmocka:

https://git.cryptomilk.org/projects/cmocka.git/tree/example/chef_wrap/CMakeLists.txt#n16

The only addition that cmocka then provides is a global data structure
that can be used to pass information from the test to the wrap function.
That data structure is only initialized when a cmocka test fixture is
used. Given that the linker wrap applies to the whole file, this would
require converting all tests to cmocka.

To allow backports, i would suggest to use the approach i submitted in
my patches. That easily applies back to 4.6 where no cmocka is in the
source tree. cmocka support could be added later, independent of the bug
fix here.

If we decide to go with cmocka anyway, the best approach would be to put
the new test in a new file and implement it completely with cmocka.
Existing tests could then be converted later.

Christof