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Date: Sun, 31 Jan 2010 16:50:01 +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,
	gregkh@suse.de, takedakn@nttdata.co.jp,
	linux-kernel@vger.kernel.org, spock@gentoo.org, mingo@redhat.com,
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	shemminger@linux-foundation.org, menage@google.com,
	abelay@mit.edu, drbd-dev@lists.linbit.com
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 01/29, Neil Horman wrote:
>
>  void do_coredump(long signr, int exit_code, struct pt_regs *regs)
>  {
> ...
> -		if (call_usermodehelper_pipe(helper_argv[0], helper_argv, NULL,
> -				&cprm.file)) {
> +		cprm.file = NULL;

it is already NULL,

> +		if (call_usermodehelper_fns(helper_argv[0], helper_argv, NULL,
> +					    UMH_WAIT_EXEC, umh_pipe_setup,
> +					    NULL, &cprm)) {
> +			if (cprm.file)
> +				filp_close(cprm.file, NULL);

Hmm. Looks like this change fixes the bug by accident.

Before this patch, I think we leak info->stdin if kernel_thread() fails
in __call_usermodehelper() pathes.



Completely off-topic, but I think __call_usermodehelper(UMH_NO_WAIT) is
buggy. if kernel_thread() failes it should do call_usermodehelper_freeinfo().
Also, UMH_WAIT_EXEC should set ->retval in this case.

Cough. And why call_usermodehelper_exec() has this strange ->path[0] == '\0'
check?

Oleg.