On Tue, Sep 11, 2018 at 02:09:11PM -0700, Yonghong Song wrote:
> Commit f7010770fbac ("tools/bpf: move bpf/lib netlink related
> functions into a new file") introduced a while loop for the
> netlink recv path. This while loop is needed since the
> buffer in recv syscall may not be enough to hold all the
> information and in such cases multiple recv calls are needed.
>
> There is a bug introduced by the above commit as
> the while loop may block on recv syscall if there is no
> more messages are expected. The netlink message header
> flag NLM_F_MULTI is used to indicate that more messages
> are expected and this patch fixed the bug by doing
> further recv syscall only if multipart message is expected.
>
> The patch added another fix regarding to message length of 0.
> When netlink recv returns message length of 0, there will be
> no more messages for returning data so the while loop
> can end.
>
> Fixes: f7010770fbac ("tools/bpf: move bpf/lib netlink related functions into
> a new file")
> Reported-by: Björn Töpel <bjorn.to...@intel.com>
> Tested-by: Björn Töpel <bjorn.to...@intel.com>
> Signed-off-by: Yonghong Song <y...@fb.com>
Applied, Thanks
