[LU-7766] LNetEQAlloc() misuses roundup_pow_of_two()

• Type: Bug
• Resolution: Fixed
• Priority: Blocker
• Fix Version/s: Lustre 2.8.0
• Severity: 3
• Assignee: Oleg Drokin
• Reporter: John Hammond

Description

After http://review.whamcloud.com/16914 we see the following when starting LNet:

[690112.179415] LNet: 8882:0:(lib-eq.c:87:LNetEQAlloc()) EQ callback is guaranteed to get every event, do you still want to set eqcount 1 for polling event which will have locking overhead? Please contact with developer to confirm

Here LNetEQAlloc() is being called with a count of 0 and passing that to roundup_pow_of_two(). This is undefined behavior according to http://lxr.free-electrons.com/source/tools/include/linux/log2.h#L161.