Re: [Valgrind-developers] Hang in err_disable4

[Paul F. <pj...@wa...>]

> 
> With --trace-sched=yes --trace-syscalls=yes I get the following (I've taken it from the mmap/mprotect, which I assume is the main thread setting up the memory for the child thread's stack).
> 
> The last line looks very interesting (I hadn't seen it before). It looks like there are 4 values of umtx_op that I'm not handling.


This seems to have pointed me in the right direction. Adding a ‘MayBlock’ to the flags for _umtx_op has fixed the problem.

A+
Paul