On Mon, 30 Nov 2020 16:57:37 +0100 Vlastimil Babka <vbabka@xxxxxxx> wrote:
> On 11/30/20 2:45 PM, Michal Hocko wrote:
> > On Mon 30-11-20 21:36:49, Muchun Song wrote:
> >> On Mon, Nov 30, 2020 at 9:23 PM Michal Hocko <mhocko@xxxxxxxx> wrote:
> >> >
> >> > On Mon 30-11-20 21:15:12, Muchun Song wrote:
> >> > > We found a case of kernel panic. The stack trace is as follows
> >> > > (omit some irrelevant information):
> >> > >
> >> > > BUG: kernel NULL pointer dereference, address: 00000000000000c8
> >> > > RIP: 0010:workingset_eviction+0x26b/0x450
> >> > > Call Trace:
> >> > > __remove_mapping+0x224/0x2b0
> >> > > shrink_page_list+0x8c2/0x14e0
> >> > > shrink_inactive_list+0x1bf/0x3f0
> >> > > ? do_raw_spin_unlock+0x49/0xc0
> >> > > ? _raw_spin_unlock+0xa/0x20
> >> > > shrink_lruvec+0x401/0x640
> >> > >
> >> > > This was caused by commit 76761ffa9ea1 ("mm/memcg: bail out early when
> >> > > !memcg in mem_cgroup_lruvec"). When the parameter of memcg is NULL, we
> >> > > should not use the &pgdat->__lruvec. So this just reverts commit
> >> > > 76761ffa9ea1 to fix it.
> >> > >
> >> > > Fixes: 76761ffa9ea1 ("mm/memcg: bail out early when !memcg in mem_cgroup_lruvec")
> >> >
> >> > I do not see any commits like that in the current Linus tree. Is this a
> >> > commit id from the linux-next? If yes, can we just fold it into the
> >> > respective patch in mmotm tree please?
> >>
> >> Yes. This commit is on the linux-next tree.
> >
> > FYI, patches coming from mmotm are constantly rebased in linux-next so
> > the sha1 is meaningless and shouldn't be added as a reference in the
> > changelog.
> >
> >> Of course can.
> >
> > Thanks! I believe Andrew should be able to just pick up the patch and
> > make it -fix patch.
>
> Well the fix is a revert, so just remove the patch from mmotm/next?
> BTW, looks like it wasn't sent to linux-mm [1], looks like missing To: header.
>
> [1]
> https://lore.kernel.org/lkml/1606446515-36069-1-git-send-email-alex.shi@xxxxxxxxxxxxxxxxx/
Yes, I've dropped "mm/memcg: bail out early when !memcg in
mem_cgroup_lruvec", thanks.
