Messages in this thread | | | Date | Thu, 24 Mar 2011 18:13:19 +0100 | From | Oleg Nesterov <> | Subject | Re: [PATCH 5/5] x86,mm: make pagefault killable |
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On 03/22, KOSAKI Motohiro wrote: > > This patch makes pagefault interruptible by SIGKILL.
Not a comment, but the question...
> --- a/arch/x86/mm/fault.c > +++ b/arch/x86/mm/fault.c > @@ -1035,6 +1035,7 @@ do_page_fault(struct pt_regs *regs, unsigned long error_code) > if (user_mode_vm(regs)) { > local_irq_enable(); > error_code |= PF_USER; > + flags |= FAULT_FLAG_KILLABLE;
OK, this is clear.
I am wondering, can't we set FAULT_FLAG_KILLABLE unconditionally but check PF_USER when we get VM_FAULT_RETRY? I mean,
if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) { if (!(error_code & PF_USER)) no_context(...); return; }
Probably not... but I can't find any example of in-kernel fault which can be broken by -EFAULT if current was killed.
mm_release()->put_user(clear_child_tid) should be fine...
Just curious, I feel I missed something obvious.
Oleg.
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