[Valgrind-users] memory barriers support

[Jan V. <jan...@ni...>]

Hello list,

we develop an authoritative DNS server called Knot DNS and we use the 
userspace-rcu library [1] for synchronization. The library implements the 
synchronization by inserting appropriate sfence/lfence/mfcence instructions 
and some reference counting around.

Currently, we are trying to track down an invalid read reported by Valgrind. 
The problem appears very rarely and it's quite difficult to reproduce. 
Valgrind claims that a previously freed memory is being read. However we quite 
sure that the synchronization is correct and that this problem should not 
happen.

Does Valgrind support the mentioned memory barrier instructions?

I'm not rejecting that there is a problem in our code, but I want to make sure 
that we are chasing a real bug.

Thanks and regards

Jan

[1] http://lttng.org/urcu