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From: Richard Henderson <richard.henderson@linaro.org>
To: Maximilian Riemensberger <riemensberger@cadami.net>,
	qemu-devel <qemu-devel@nongnu.org>
Cc: Peter Maydell <peter.maydell@linaro.org>,
	Riku Voipio <riku.voipio@iki.fi>,
	Laurent Vivier <laurent@vivier.eu>
Subject: Re: [Qemu-devel] [PATCH v2] linux-user/mmap.c: Avoid choosing NULL as start address
Date: Mon, 8 Jan 2018 12:28:05 -0800	[thread overview]
Message-ID: <cefe5369-bb7b-d9c0-6e91-c47cdd60e96c@linaro.org> (raw)
In-Reply-To: <1515286904-86418-1-git-send-email-riemensberger@cadami.net>

On 01/06/2018 05:01 PM, Maximilian Riemensberger wrote:
> mmap() is required by the linux kernel ABI and POSIX to return a
> non-NULL address when the implementation chooses a start address for the
> mapping.
> 
> The current implementation of mmap_find_vma_reserved() can return NULL
> as start address of a mapping which leads to subsequent crashes inside
> the guests glibc, e.g. output of qemu-arm-static --strace executing a
> test binary stx_test:
> 
>     1879 mmap2(NULL,8388608,PROT_READ|PROT_WRITE,MAP_PRIVATE|MAP_ANONYMOUS|0x20000,-1,0) = 0x00000000
>     1879 write(2,0xf6fd39d0,79) stx_test: allocatestack.c:514: allocate_stack: Assertion `mem != NULL' failed.
> 
> This patch fixes mmap_find_vma_reserved() by skipping NULL as start
> address while searching for a suitable mapping start address.
> 
> CC: Riku Voipio <riku.voipio@iki.fi>
> CC: Laurent Vivier <laurent@vivier.eu>
> CC: Peter Maydell <peter.maydell@linaro.org>
> Signed-off-by: Maximilian Riemensberger <riemensberger@cadami.net>
> ---
> Changes since v1:
>     - Applied feedback from Laurent Vivier

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>


r~

  parent reply	other threads:[~2018-01-08 20:30 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-07  1:01 [Qemu-devel] [PATCH v2] linux-user/mmap.c: Avoid choosing NULL as start address Maximilian Riemensberger
2018-01-07 12:39 ` Laurent Vivier
2018-01-08 20:28 ` Richard Henderson [this message]
2018-01-19 16:34 ` Laurent Vivier

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