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Date: Sat, 19 Apr 2014 20:04:21 +0200
From: Oleg Nesterov <oleg@redhat.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Neil Horman <nhorman@tuxdriver.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Hugh Dickins <hughd@google.com>
Subject: Re: [PATCH] coredump: fix va_list corruption
Message-ID: <20140419180421.GA982@redhat.com>
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On 04/19, Eric Dumazet wrote:
>
> A va_list needs to be copied in case it needs to be used twice.

OOPS :/

> --- a/fs/coredump.c
> +++ b/fs/coredump.c
> @@ -73,10 +73,15 @@ static int expand_corename(struct core_name *cn, int size)
>  static int cn_vprintf(struct core_name *cn, const char *fmt, va_list arg)
>  {
>  	int free, need;
> +	va_list arg_copy;
>
>  again:
>  	free = cn->size - cn->used;
> -	need = vsnprintf(cn->corename + cn->used, free, fmt, arg);
> +
> +	va_copy(arg_copy, arg);
> +	need = vsnprintf(cn->corename + cn->used, free, fmt, arg_copy);
> +	va_end(arg_copy);
> +

Thanks!

Acked-by: Oleg Nesterov <oleg@redhat.com>