linux-kernel - Re: 'khelper' (child) is stuck in endless loop: do_signal() and !user

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Message-ID: <20120308160843.GA12204@redhat.com>
Date:	Thu, 8 Mar 2012 17:08:43 +0100
From:	Oleg Nesterov <oleg@...hat.com>
To:	"Dmitry ADAMUSHKA (EXT)" <dmitry.adamushka_ext@...tathome.com>
Cc:	Ingo Molnar <mingo@...e.hu>, Ralf Baechle <ralf@...ux-mips.org>,
	wouter cloetens <wouter.cloetens@...tathome.com>,
	linux-kernel@...r.kernel.org,
	Dmitry Adamushko <dmitry.adamushko@...il.com>
Subject: Re: 'khelper' (child) is stuck in endless loop: do_signal() and
	!user_mode(regs)

On 03/08, Dmitry ADAMUSHKA (EXT) wrote:
>
> And to simplify a real-life test case: it's enough for khelper's child task,
> while it's running in ____call_usermodehelper(), to receive SIGKILL.
> In this case, do_execve_common() will fail - there are a number of
> fatal_signal_pending(current) checks in there.

Actually there is no difference, SIGUSR1 equally kills the task and
makes fatal_signal_pending() true. The handler is SIG_DFL after
flush_signal_handlers(), complete_signal() adds SIGKILL implicitely.

Not that this actually matters.

Oleg.

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