On Mon, 2017-01-02 at 14:14 -0700, Jason Gunthorpe wrote: > I felt that passing uninitialized memory into the kernel was just > in general a bad idea, and adding the branchs to copy zero instead of > un-init is probably performance neutral. > > Even so, I don't think we can fix valgrind, ioctl is a different case > as ioctls are much more well defined, this is write() and valgrind > would have to first know we are writing to a uverbs FD which seems > challenging to determine, can valgrind already do this? Hello Jason, As far as I know there is not yet any code in Valgrind to interpret the data sent from user space to kernel through the write() system call. Since I do not know any application for which ibv_modify_qp() is in the hot path I think modifying the ibv_modify_qp() implementation is fine. Bart.��.n��������+%������w��{.n�����{���fk��ܨ}���Ơz�j:+v�����w����ޙ��&�)ߡ�a����z�ޗ���ݢj��w�f