linux-kernel - Re: [PATCH 1/4] printk: Allocate kernel log buffer earlier

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Date:	Mon, 28 Feb 2011 11:18:11 -0800
From:	Yinghai Lu <yinghai@...nel.org>
To:	Ingo Molnar <mingo@...e.hu>
Cc:	Mike Travis <travis@....com>, David Rientjes <rientjes@...gle.com>,
	Jack Steiner <steiner@....com>, Robin Holt <holt@....com>,
	Len Brown <len.brown@...el.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	"H. Peter Anvin" <hpa@...or.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	linux-acpi@...r.kernel.org, x86@...nel.org,
	linux-kernel@...r.kernel.org, Tejun Heo <tj@...nel.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: [PATCH 1/4] printk: Allocate kernel log buffer earlier

On Mon, Feb 28, 2011 at 12:06 AM, Ingo Molnar <mingo@...e.hu> wrote:
>
> * Yinghai Lu <yinghai@...nel.org> wrote:
>
>> +     new_addr = memblock_alloc(new_log_buf_len, PAGE_SIZE);
>> +     if (new_addr != MEMBLOCK_ERROR)
>> +             new_log_buf = __va(new_addr);
>> +     else
>> +             new_log_buf = alloc_bootmem(new_log_buf_len);
>
> alloc_bootmem() can fail, especially if someone uses a too large boot parameter
> value - and your code does not check for failure.

alloc_bootmem will panic if it fails.

static void * __init ___alloc_bootmem(unsigned long size, unsigned long align,
                                        unsigned long goal, unsigned long limit)
{
        void *mem = ___alloc_bootmem_nopanic(size, align, goal, limit);

        if (mem)
                return mem;
        /*
         * Whoops, we cannot satisfy the allocation request.
         */
        printk(KERN_ALERT "bootmem alloc of %lu bytes failed!\n", size);
        panic("Out of memory");
        return NULL;
}

so it should be ok.
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