Messages in this thread | | | Date | Tue, 5 May 2009 16:47:33 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH 1/3] ptrace: ptrace_attach: check PF_KTHREAD + exit_state instead of ->mm |
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On Wed, 6 May 2009 00:47:22 +0200 Oleg Nesterov <oleg@redhat.com> wrote:
> - Add PF_KTHREAD check to prevent attaching to the kernel thread > with a borrowed ->mm. > > With or without this change we can race with daemonize() which > can set PF_KTHREAD or clear ->mm after ptrace_attach() does the > check, but this doesn't matter because reparent_to_kthreadd() > does ptrace_unlink(). > > - Kill "!task->mm" check. We don't really care about ->mm != NULL, > and the task can call exit_mm() right after we drop task_lock(). > What we need is to make sure we can't attach after exit_notify(), > check task->exit_state != 0 instead. >
These patches make a mess of utrace-core.patch. Do we really want to do that?
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