| Message ID | 20171030135124.19189-1-aryabinin@virtuozzo.com |
|---|---|
| State | New |
| Series | "Series without cover letter" |
| Headers | show |
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 239fbca70b59..efc455d8ca81 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -3597,15 +3597,14 @@ static int mem_cgroup_move_account(struct page *page, /* caller should have done css_get */ pc->mem_cgroup = to; - move_unlock_mem_cgroup(from, &flags); + spin_unlock(&from->move_lock); ret = 0; - local_irq_disable(); mem_cgroup_charge_statistics(to, page, nr_pages); memcg_check_events(to, page); mem_cgroup_charge_statistics(from, page, -nr_pages); memcg_check_events(from, page); - local_irq_enable(); + local_irq_restore(flags); out_unlock: unlock_page(page); out:
Please consider to apply these patches a as ReadyKernel patch after they pass QA in the scope of vz7 update 6. https://readykernel.com/ -- Best regards, Konstantin Khorenko, Virtuozzo Linux Kernel Team On 10/30/2017 04:51 PM, Andrey Ryabinin wrote: > When mem_cgroup_move_parent() moves huge page it disables interrupt: > > if (nr_pages > 1) { > VM_BUG_ON_PAGE(!PageTransHuge(page), page); > flags = compound_lock_irqsave(page); > } > > and calls: > ret = mem_cgroup_move_account(page, nr_pages, ... > > which does the following: > > local_irq_disable(); > mem_cgroup_charge_statistics(to, page, nr_pages); > ... > local_irq_enable(); > > So the last local_irq_enable() enables irq too early, which may lead > to the deadlock. mem_cgroup_move_account() should use local_irq_save()/ > local_irq_restore() primitives instead. > > Found while investigating https://jira.sw.ru/browse/PSBM-76011 > but unrelated. > > Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> > --- > mm/memcontrol.c | 5 ++--- > 1 file changed, 2 insertions(+), 3 deletions(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index 239fbca70b59..efc455d8ca81 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -3597,15 +3597,14 @@ static int mem_cgroup_move_account(struct page *page, > > /* caller should have done css_get */ > pc->mem_cgroup = to; > - move_unlock_mem_cgroup(from, &flags); > + spin_unlock(&from->move_lock); > ret = 0; > > - local_irq_disable(); > mem_cgroup_charge_statistics(to, page, nr_pages); > memcg_check_events(to, page); > mem_cgroup_charge_statistics(from, page, -nr_pages); > memcg_check_events(from, page); > - local_irq_enable(); > + local_irq_restore(flags); > out_unlock: > unlock_page(page); > out: >
When mem_cgroup_move_parent() moves huge page it disables interrupt: if (nr_pages > 1) { VM_BUG_ON_PAGE(!PageTransHuge(page), page); flags = compound_lock_irqsave(page); } and calls: ret = mem_cgroup_move_account(page, nr_pages, ... which does the following: local_irq_disable(); mem_cgroup_charge_statistics(to, page, nr_pages); ... local_irq_enable(); So the last local_irq_enable() enables irq too early, which may lead to the deadlock. mem_cgroup_move_account() should use local_irq_save()/ local_irq_restore() primitives instead. Found while investigating https://jira.sw.ru/browse/PSBM-76011 but unrelated. Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> --- mm/memcontrol.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)