Subject: Re: Kernel 3.18.55 compilation fails (missing function declaration)
To: Emmanuel Florac <eflorac@intellique.com>, linux-kernel@vger.kernel.org
References: <20170602153047.2978ee6c@harpe.intellique.com>
From: Randy Dunlap <rdunlap@infradead.org>
Message-ID: <478288e7-0e14-0949-15ed-fc54ca13675f@infradead.org>
Date: Thu, 8 Jun 2017 15:10:45 -0700
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On 06/02/17 06:30, Emmanuel Florac wrote:
> Hi, kernel 3.18.55 compilation fails with this error:
> 
> kernel/fork.c: In function ‘dup_task_struct’:
> kernel/fork.c:341:2: error: implicit declaration of function
> ‘get_random_long’ [-Werror=implicit-function-declaration]
> tsk->stack_canary = get_random_long();
> 
> Corrected by adding the declaration to include/linux/random.h line 26 :
> 
>  unsigned long get_random_long(void);
> 
> Sorry, I really can't understand how to generate a patch from a tagged
> release, my git-fu is far too low...
> 

Should be fixed in 3.18.56 by this commit:


commit 2bc281ebacf969770597fad415547016f0457b53
Author: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date:   Sat May 27 12:09:37 2017 +0200

    Revert "stackprotector: Increase the per-task stack canary's random range from 32 bits to 64 bits on 64-bit platforms"
    
    This reverts commit 609a3e81550b0b4ea87197b0f59455a7bcff975a which is
    commit 5ea30e4e58040cfd6434c2f33dc3ea76e2c15b05 upstream.
    
    It shouldn't have been backported to 3.18, as we do not have
    get_random_long() in that kernel tree.


-- 
~Randy