On Sun, Jan 06, 2013 at 06:24:47PM +0100, Antti Kantee wrote: >[I'd submit this to cygwin-patches, but the web page says only >subscribers can post to that list, so please bear with me for this >simple issue] > >Hi, > >Calling pthread_rwlock_tryrdlock() twice from the same thread always >fails with EBUSY the second time. See attached test.c. Replacing the >second tryrdlock() with rdlock() makes the call succeed, leading me to >believe there is a bug in tryrdlock(). > >Assuming I was looking at the correct source file, the attached patch >should fix the issue. I'm not sure why the lookup_reader() call was >there in the first place; perhaps a remnant from a time when recursive >read locking was not supported? > >While looking at tryrdlock(), the handling of ULONG_MAX also seems >wrong, as you'd probably want to return EAGAIN instead of allocating >another reader structure. However, that problem is arguably more of an >academic issue and therefore I didn't touch it in my patch.
Thanks for the analysis and patch. I've made a few more changes to this function and should have everything checked in tomorrow. cgf -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple
