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Date: Mon, 1 Feb 2010 11:39:33 +0100
From: Oleg Nesterov <oleg@redhat.com>
To: Neil Horman <nhorman@tuxdriver.com>
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Cc: jmoskovc@redhat.com, neilb@suse.de, benh@kernel.crashing.org,
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Subject: Re: [Drbd-dev] [PATCH 2/2] exec: allow core_pipe recursion check to
	look for	a value of 1 rather than 0 (v2)
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On 02/01, Oleg Nesterov wrote:
>
> Oh. And in theory, it is better to change wait_for_helper(). It should
> do allow_signal(SIGCHLD) after kernel_thread(). Otherwise, kernel_thread()
> can fail if user-space sends SIGCHLD to the forking thread.

Well ;) And since allow_signal(SIGCHLD) was called, in theory we should
call sys_wait4() + clear_thread_flag(TIF_SIGPENDING) in a loop to protect
against the false SIGCHLD.

> > > Cough. And why call_usermodehelper_exec() has this strange ->path[0] == '\0'
> > > check?
> > >
> > That I can't explain.  I figured I'd let that sleeping dog lie until this got
> > striaghtened out and fix it separately if it needed it
> > Neil
>
> Yes, yes, agreed. As I said, this has nothing to do with this series,
> even if I am right these (minor) bugs should be fixed separately.

Yes.

Oleg.