1. vma_policy_mof(task) is simply not safe unless task == current, it can race with do_exit()->mpol_put(). Remove this arg and update its single caller.
2. vma can not be NULL, remove this check and simplify the code. Signed-off-by: Oleg Nesterov <[email protected]> --- include/linux/mempolicy.h | 2 +- kernel/sched/fair.c | 2 +- mm/mempolicy.c | 25 +++++++++++-------------- 3 files changed, 13 insertions(+), 16 deletions(-) diff --git a/include/linux/mempolicy.h b/include/linux/mempolicy.h index f230a97..5e4bfce 100644 --- a/include/linux/mempolicy.h +++ b/include/linux/mempolicy.h @@ -136,7 +136,7 @@ struct mempolicy *mpol_shared_policy_lookup(struct shared_policy *sp, struct mempolicy *get_vma_policy(struct task_struct *tsk, struct vm_area_struct *vma, unsigned long addr); -bool vma_policy_mof(struct task_struct *task, struct vm_area_struct *vma); +bool vma_policy_mof(struct vm_area_struct *vma); extern void numa_default_policy(void); extern void numa_policy_init(void); diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index bfa3c86..82088b2 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -1946,7 +1946,7 @@ void task_numa_work(struct callback_head *work) vma = mm->mmap; } for (; vma; vma = vma->vm_next) { - if (!vma_migratable(vma) || !vma_policy_mof(p, vma)) + if (!vma_migratable(vma) || !vma_policy_mof(vma)) continue; /* diff --git a/mm/mempolicy.c b/mm/mempolicy.c index b86b08e..ad27bbc 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -1646,27 +1646,24 @@ struct mempolicy *get_vma_policy(struct task_struct *task, return pol; } -bool vma_policy_mof(struct task_struct *task, struct vm_area_struct *vma) +bool vma_policy_mof(struct vm_area_struct *vma) { - struct mempolicy *pol = NULL; - - if (vma) { - if (vma->vm_ops && vma->vm_ops->get_policy) { - bool ret = false; + struct mempolicy *pol; - pol = vma->vm_ops->get_policy(vma, vma->vm_start); - if (pol && (pol->flags & MPOL_F_MOF)) - ret = true; - mpol_cond_put(pol); + if (vma->vm_ops && vma->vm_ops->get_policy) { + bool ret = false; - return ret; - } + pol = vma->vm_ops->get_policy(vma, vma->vm_start); + if (pol && (pol->flags & MPOL_F_MOF)) + ret = true; + mpol_cond_put(pol); - pol = vma->vm_policy; + return ret; } + pol = vma->vm_policy; if (!pol) - pol = get_task_policy(task); + pol = get_task_policy(current); return pol->flags & MPOL_F_MOF; } -- 1.5.5.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
