From fec1e5f987bfc41f9f08cbd206e7302e6ac2ab0c Mon Sep 17 00:00:00 2001 From: Michal Hocko Date: Thu, 28 Jul 2016 15:45:19 -0700 Subject: [PATCH] cpuset, mm: fix TIF_MEMDIE check in cpuset_change_task_nodemask Commit c0ff7453bb5c ("cpuset,mm: fix no node to alloc memory when changing cpuset's mems") has added TIF_MEMDIE and PF_EXITING check but it is checking the flag on the current task rather than the given one. This doesn't make much sense and it is actually wrong. If the current task which updates the nodemask of a cpuset got killed by the OOM killer then a part of the cpuset cgroup processes would have incompatible nodemask which is surprising to say the least. The comment suggests the intention was to skip oom victim or an exiting task so we should be checking the given task. But even then it would be layering violation because it is the memory allocator to interpret the TIF_MEMDIE meaning. Simply drop both checks. All tasks in the cpuset should simply follow the same mask. Link: http://lkml.kernel.org/r/1467029719-17602-3-git-send-email-mhocko@kernel.org Signed-off-by: Michal Hocko Cc: David Rientjes Cc: Miao Xie Cc: Miao Xie Cc: "Rafael J. Wysocki" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/cpuset.c | 9 --------- 1 file changed, 9 deletions(-) diff --git a/kernel/cpuset.c b/kernel/cpuset.c index 73e93e53884d..c7fd2778ed50 100644 --- a/kernel/cpuset.c +++ b/kernel/cpuset.c @@ -1034,15 +1034,6 @@ static void cpuset_change_task_nodemask(struct task_struct *tsk, { bool need_loop; - /* - * Allow tasks that have access to memory reserves because they have - * been OOM killed to get memory anywhere. - */ - if (unlikely(test_thread_flag(TIF_MEMDIE))) - return; - if (current->flags & PF_EXITING) /* Let dying task have memory */ - return; - task_lock(tsk); /* * Determine if a loop is necessary if another thread is doing