The patch titled cpusets: prevent PF_THREAD_BOUND tasks from attaching to non-root cpusets has been added to the -mm tree. Its filename is cpusets-prevent-pf_thread_bound-tasks-from-attaching-to-non-root-cpusets.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 *** See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: cpusets: prevent PF_THREAD_BOUND tasks from attaching to non-root cpusets From: David Rientjes <rientjes@xxxxxxxxxx> Kthreads that have the PF_THREAD_BOUND bit set in their flags are bound to a specific cpu. Thus, their set of allowed cpus shall not change. This patch prevents such threads from attaching to non-root cpusets. They do not have mempolicies that restrict them to a subset of system nodes and, since their cpumask may never change, they cannot use any of the features of cpusets. The tasks will forever be a member of the root cpuset and will be returned when listing the tasks attached to that cpuset. Cc: Paul Menage <menage@xxxxxxxxxx> Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> Cc: Dhaval Giani <dhaval@xxxxxxxxxxxxxxxxxx> Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxx> Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- kernel/cpuset.c | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) diff -puN kernel/cpuset.c~cpusets-prevent-pf_thread_bound-tasks-from-attaching-to-non-root-cpusets kernel/cpuset.c --- a/kernel/cpuset.c~cpusets-prevent-pf_thread_bound-tasks-from-attaching-to-non-root-cpusets +++ a/kernel/cpuset.c @@ -1342,19 +1342,22 @@ static int cpuset_can_attach(struct cgro struct cgroup *cont, struct task_struct *tsk) { struct cpuset *cs = cgroup_cs(cont); - int ret = 0; if (cpumask_empty(cs->cpus_allowed) || nodes_empty(cs->mems_allowed)) return -ENOSPC; - if (tsk->flags & PF_THREAD_BOUND) { - mutex_lock(&callback_mutex); - if (!cpumask_equal(&tsk->cpus_allowed, cs->cpus_allowed)) - ret = -EINVAL; - mutex_unlock(&callback_mutex); - } + /* + * Kthreads bound to specific cpus cannot be moved to a new cpuset; we + * cannot change their cpu affinity and isolating such threads by their + * set of allowed nodes is unnecessary. Thus, cpusets are not + * applicable for such threads. This prevents checking for success of + * set_cpus_allowed_ptr() on all attached tasks before cpus_allowed may + * be changed. + */ + if (tsk->flags & PF_THREAD_BOUND) + return -EINVAL; - return ret < 0 ? ret : security_task_setscheduler(tsk, 0, NULL); + return security_task_setscheduler(tsk, 0, NULL); } static void cpuset_attach(struct cgroup_subsys *ss, _ Patches currently in -mm which might be from rientjes@xxxxxxxxxx are linux-next.patch oom_kill-dont-call-for-int_sqrt0.patch page_fault-retry-with-nopage_retry.patch page_fault-retry-with-nopage_retry-fix.patch memcg-use-css-id.patch memcg-hierarchical-stat.patch memcg-fix-shrinking-memory-to-return-ebusy-by-fixing-retry-algorithm.patch memcg-fix-oom-killer-under-memcg.patch memcg-fix-oom-killer-under-memcg-fix2.patch memcg-fix-oom-killer-under-memcg-fix.patch memcg-show-memcg-information-during-oom.patch memcg-show-memcg-information-during-oom-fix2.patch memcg-show-memcg-information-during-oom-fix.patch memcg-show-memcg-information-during-oom-fix-fix.patch memcg-show-memcg-information-during-oom-fix-fix-checkpatch-fixes.patch cpusets-replace-zone-allowed-functions-with-node-allowed.patch cpusets-prevent-pf_thread_bound-tasks-from-attaching-to-non-root-cpusets.patch cpuset-check-if-the-cpus-allowed-is-a-subset-of-the-cpusets-cpus-for-pf_thread_bound-threads.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