Messages in this thread Patch in this message | | | Subject | [PATCH]: exec: avoid propagating PF_NO_SETAFFINITY into userspace child | From | zhang.yi20@zte ... | Date | Fri, 29 Nov 2013 17:19:21 +0800 |
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Khelper is a workqueue thread which has PF_NO_SETAFFINITY set. When a usermode process is spawned by khelper through __call_usermodehelper() which will invoke kernel_thread() (not kthread_create()) to fork the new process, we will clearly see that it will inherit the PF_NO_SETAFFINITY flag.
Consequently, this usermod process will lose some capabilities like sched_setaffinity(), moving between cgroups, etc.
Clearing this flag in flush_old_exec() to solve this problem.
Signed-off-by: Zhang Yi <zhang.yi20@zte.com.cn> Signed-off-by: Pang Xunlei <pang.xunlei@zte.com.cn>
--- linux-3.12.old/fs/exec.c 2013-11-26 08:53:12.175811856 +0000 +++ linux-3.12/fs/exec.c 2013-11-27 09:36:56.231972168 +0000 @@ -1090,8 +1090,8 @@ int flush_old_exec(struct linux_binprm * bprm->mm = NULL; /* We're using it now */
set_fs(USER_DS); - current->flags &= - ~(PF_RANDOMIZE | PF_FORKNOEXEC | PF_KTHREAD | PF_NOFREEZE); + current->flags &= ~(PF_RANDOMIZE | PF_FORKNOEXEC | PF_KTHREAD | + PF_NOFREEZE | PF_NO_SETAFFINITY); flush_thread(); current->personality &= ~bprm->per_clear;
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