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Subject: Re: [PATCH 176/190] Revert "net/net_namespace: Check the return value
 of register_pernet_subsys()"
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-kernel@vger.kernel.org
Cc:     Aditya Pakki <pakki001@umn.edu>,
        "David S . Miller" <davem@davemloft.net>
References: <20210421130105.1226686-1-gregkh@linuxfoundation.org>
 <20210421130105.1226686-177-gregkh@linuxfoundation.org>
From:   Kirill Tkhai <ktkhai@virtuozzo.com>
Message-ID: <c4cdd3fe-0fd1-c328-14f4-e428eee1d02c@virtuozzo.com>
Date:   Wed, 21 Apr 2021 23:45:26 +0300
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On 21.04.2021 16:00, Greg Kroah-Hartman wrote:
> This reverts commit 0eb987c874dc93f9c9d85a6465dbde20fdd3884c.
> 
> Commits from @umn.edu addresses have been found to be submitted in "bad
> faith" to try to test the kernel community's ability to review "known
> malicious" changes.  The result of these submissions can be found in a
> paper published at the 42nd IEEE Symposium on Security and Privacy
> entitled, "Open Source Insecurity: Stealthily Introducing
> Vulnerabilities via Hypocrite Commits" written by Qiushi Wu (University
> of Minnesota) and Kangjie Lu (University of Minnesota).
> 
> Because of this, all submissions from this group must be reverted from
> the kernel tree and will need to be re-reviewed again to determine if
> they actually are a valid fix.  Until that work is complete, remove this
> change to ensure that no problems are being introduced into the
> codebase.
> 
> Cc: Aditya Pakki <pakki001@umn.edu>
> Cc: Kirill Tkhai <ktkhai@virtuozzo.com>
> Cc: David S. Miller <davem@davemloft.net>
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> ---
>  net/core/net_namespace.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
> index 43b6ac4c4439..9ae0b275238e 100644
> --- a/net/core/net_namespace.c
> +++ b/net/core/net_namespace.c
> @@ -1101,8 +1101,7 @@ static int __init net_ns_init(void)
>  	init_net_initialized = true;
>  	up_write(&pernet_ops_rwsem);
>  
> -	if (register_pernet_subsys(&net_ns_ops))
> -		panic("Could not register network namespace subsystems");
> +	register_pernet_subsys(&net_ns_ops);

Nacked-by: Kirill Tkhai <ktkhai@virtuozzo.com>

This patch does not have any problem, since it has been already carefully reviewed.
Kernel panics here only, if we can't allocate ns_common::inum for init_net.
This can be only a result of a critical deficiency of memory during boot.