The patch titled Subject: kernel/taskstats: fix wrong nla type for {cgroup,task}stats policy has been added to the -mm tree. Its filename is kernel-taskstats-fix-wrong-nla-type-for-cgrouptaskstats-policy.patch

This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/kernel-taskstats-fix-wrong-nla-type... and later at http://ozlabs.org/~akpm/mmotm/broken-out/kernel-taskstats-fix-wrong-nla-type...

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------------------------------------------------------ From: Yafang Shao laoar.shao@gmail.com Subject: kernel/taskstats: fix wrong nla type for {cgroup,task}stats policy

After our server is upgraded to a newer kernel, we found that it continuesly print a warning in the kernel message. The warning is,

[832984.946322] netlink: 'irmas.lc': attribute type 1 has an invalid length.

irmas.lc is one of our container monitor daemons, and it will use CGROUPSTATS_CMD_GET to get the cgroupstats, that is similar with tools/accounting/getdelays.c. We can also produce this warning with getdelays. For example, after running bellow command

$ ./getdelays -C /sys/fs/cgroup/memory

then you can find a warning in dmesg, [61607.229318] netlink: 'getdelays': attribute type 1 has an invalid length.

This warning is introduced in commit 6e237d099fac ("netlink: Relax attr validation for fixed length types"), which is used to check whether attributes using types NLA_U* and NLA_S* have an exact length.

Regarding this issue, the root cause is cgroupstats_cmd_get_policy defines a wrong type as NLA_U32, while it should be NLA_NESTED an its minimal length is NLA_HDRLEN. That is similar to taskstats_cmd_get_policy.

As this behavior change really breaks our application, we'd better cc stable as well.

Link: http://lkml.kernel.org/r/1585191042-9935-1-git-send-email-laoar.shao@gmail.c... Signed-off-by: Yafang Shao laoar.shao@gmail.com Cc: Balbir Singh bsingharora@gmail.com Cc: David Ahern dsahern@gmail.com Cc: David S. Miller davem@davemloft.net Cc: Johannes Berg johannes@sipsolutions.net Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

kernel/taskstats.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/kernel/taskstats.c~kernel-taskstats-fix-wrong-nla-type-for-cgrouptaskstats-policy +++ a/kernel/taskstats.c @@ -35,8 +35,8 @@ struct kmem_cache *taskstats_cache; static struct genl_family family;

static const struct nla_policy taskstats_cmd_get_policy[TASKSTATS_CMD_ATTR_MAX+1] = { - [TASKSTATS_CMD_ATTR_PID] = { .type = NLA_U32 }, - [TASKSTATS_CMD_ATTR_TGID] = { .type = NLA_U32 }, + [TASKSTATS_CMD_ATTR_PID] = { .type = NLA_NESTED }, + [TASKSTATS_CMD_ATTR_TGID] = { .type = NLA_NESTED }, [TASKSTATS_CMD_ATTR_REGISTER_CPUMASK] = { .type = NLA_STRING }, [TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK] = { .type = NLA_STRING },};

@@ -45,7 +45,7 @@ static const struct nla_policy taskstats * Make sure they are always aligned. */ static const struct nla_policy cgroupstats_cmd_get_policy[TASKSTATS_CMD_ATTR_MAX+1] = { - [CGROUPSTATS_CMD_ATTR_FD] = { .type = NLA_U32 }, + [CGROUPSTATS_CMD_ATTR_FD] = { .type = NLA_NESTED }, };

struct listener { _

Patches currently in -mm which might be from laoar.shao@gmail.com are

kernel-taskstats-fix-wrong-nla-type-for-cgrouptaskstats-policy.patch mm-memcg-fix-build-error-around-the-usage-of-kmem_caches.patch