The patch titled Subject: mm: memcontrol: add sanity checks for memcg->id.ref on get/put has been added to the -mm tree. Its filename is mm-memcontrol-add-sanity-checks-for-memcg-idref-on-get-put.patch This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/mm-memcontrol-add-sanity-checks-for-memcg-idref-on-get-put.patch and later at http://ozlabs.org/~akpm/mmotm/broken-out/mm-memcontrol-add-sanity-checks-for-memcg-idref-on-get-put.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx> Subject: mm: memcontrol: add sanity checks for memcg->id.ref on get/put Link: http://lkml.kernel.org/r/1c5ddb1c171dbdfc3262252769d6138a29b35b70.1470219853.git.vdavydov@xxxxxxxxxxxxx Signed-off-by: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx> Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx> Acked-by: Michal Hocko <mhocko@xxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/memcontrol.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff -puN mm/memcontrol.c~mm-memcontrol-add-sanity-checks-for-memcg-idref-on-get-put mm/memcontrol.c --- a/mm/memcontrol.c~mm-memcontrol-add-sanity-checks-for-memcg-idref-on-get-put +++ a/mm/memcontrol.c @@ -4049,6 +4049,7 @@ static DEFINE_IDR(mem_cgroup_idr); static void mem_cgroup_id_get_many(struct mem_cgroup *memcg, unsigned int n) { + VM_BUG_ON(atomic_read(&memcg->id.ref) <= 0); atomic_add(n, &memcg->id.ref); } @@ -4072,6 +4073,7 @@ static struct mem_cgroup *mem_cgroup_id_ static void mem_cgroup_id_put_many(struct mem_cgroup *memcg, unsigned int n) { + VM_BUG_ON(atomic_read(&memcg->id.ref) < n); if (atomic_sub_and_test(n, &memcg->id.ref)) { idr_remove(&mem_cgroup_idr, memcg->id.id); memcg->id.id = 0; @@ -4260,8 +4262,10 @@ fail: static int mem_cgroup_css_online(struct cgroup_subsys_state *css) { + struct mem_cgroup *memcg = mem_cgroup_from_css(css); + /* Online state pins memcg ID, memcg ID pins CSS */ - mem_cgroup_id_get(mem_cgroup_from_css(css)); + atomic_set(&memcg->id.ref, 1); css_get(css); return 0; } _ Patches currently in -mm which might be from vdavydov@xxxxxxxxxxxxx are mm-memcontrol-fix-swap-counter-leak-on-swapout-from-offline-cgroup.patch mm-memcontrol-fix-swap-counter-leak-on-swapout-from-offline-cgroup-fix.patch mm-memcontrol-fix-memcg-id-ref-counter-on-swap-charge-move.patch mm-oom-deduplicate-victim-selection-code-for-memcg-and-global-oom.patch mm-memcontrol-add-sanity-checks-for-memcg-idref-on-get-put.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html