On Thu, Jul 09, 2020 at 11:59:09AM -0700, Cong Wang wrote: > On Thu, Jul 9, 2020 at 11:51 AM Cong Wang <xiyou.wangc...@gmail.com> wrote: > > > > On Thu, Jul 9, 2020 at 10:10 AM Guenter Roeck <li...@roeck-us.net> wrote: > > > > > > Something seems fishy with the use of skcd->val on big endian systems. > > > > > > Some debug output: > > > > > > [ 22.643703] sock: ##### sk_alloc(sk=000000001be28100): Calling > > > cgroup_sk_alloc(000000001be28550) > > > [ 22.643807] cgroup: ##### cgroup_sk_alloc(skcd=000000001be28550): > > > cgroup_sk_alloc_disabled=0, in_interrupt: 0 > > > [ 22.643886] cgroup: #### cgroup_sk_alloc(skcd=000000001be28550): > > > cset->dfl_cgrp=0000000001224040, skcd->val=0x1224040 > > > [ 22.643957] cgroup: ###### cgroup_bpf_get(cgrp=0000000001224040) > > > [ 22.646451] sock: ##### sk_prot_free(sk=000000001be28100): Calling > > > cgroup_sk_free(000000001be28550) > > > [ 22.646607] cgroup: #### sock_cgroup_ptr(skcd=000000001be28550) -> > > > 0000000000014040 [v=14040, skcd->val=14040] > > > [ 22.646632] cgroup: ####### cgroup_sk_free(): skcd=000000001be28550, > > > cgrp=0000000000014040 > > > [ 22.646739] cgroup: ####### cgroup_sk_free(): skcd->no_refcnt=0 > > > [ 22.646814] cgroup: ####### cgroup_sk_free(): Calling > > > cgroup_bpf_put(cgrp=0000000000014040) > > > [ 22.646886] cgroup: ###### cgroup_bpf_put(cgrp=0000000000014040) > > > > Excellent debugging! I thought it was a double put, but it seems to > > be an endian issue. I didn't realize the bit endian machine actually > > packs bitfields in a big endian way too... > > > > Does the attached patch address this? > > Ah, this is too ugly. We just have to always make them the last two bits. > > Please test this attached patch instead and ignore the previous one. >
Sorry, that one came too late; I was already about to leave when I got the first one. It looks correct, though. I'll be back Monday night and will have another look then (and I guess my builders will pick it up after Dave sends it all to Linus). I'll let you know if I still see a problem. Thanks, Guenter
