Acked-by: Hao Luo <haoluo@xxxxxxxxxx>
On Sun, Jan 10, 2021 at 8:05 PM Yonghong Song <yhs@xxxxxx> wrote:
>
>
>
> On 1/8/21 2:09 PM, Andrii Nakryiko wrote:
> > If some of the subtests use module BTFs through ksyms, they will cause
> > bpf_prog to take a refcount on bpf_testmod module, which will prevent it from
> > successfully unloading. Module's refcnt is decremented when bpf_prog is freed,
> > which generally happens in RCU callback. So we need to trigger
> > syncronize_rcu() in the kernel, which can be achieved nicely with
> > membarrier(MEMBARRIER_CMD_GLOBAL) syscall. So do that in kernel_sync_rcu() and
> > make it available to other test inside the test_progs. This synchronize_rcu()
> > is called before attempting to unload bpf_testmod.
> >
> > Fixes: 9f7fa225894c ("selftests/bpf: Add bpf_testmod kernel module for testing")
> > Suggested-by: Alexei Starovoitov <ast@xxxxxxxxxx>
> > Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
>
> Acked-by: Yonghong Song <yhs@xxxxxx>
