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From: Jason Gunthorpe <jgg@ziepe.ca>
To: Liu Zixian <liuzixian4@huawei.com>
Cc: akpm@linux-foundation.org, linmiaohe@huawei.com,
	louhongxiang@huawei.com, linux-mm@kvack.org,
	hushiyuan@huawei.com, stable@vger.kernel.org
Subject: Re: [PATCH v2] fix mmap return value when vma is merged after call_mmap()
Date: Fri, 4 Dec 2020 11:11:09 -0400	[thread overview]
Message-ID: <20201204151109.GA5487@ziepe.ca> (raw)
In-Reply-To: <20201203085350.22624-1-liuzixian4@huawei.com>

On Thu, Dec 03, 2020 at 04:53:50PM +0800, Liu Zixian wrote:
> On success, mmap should return the begin address of newly mapped area,
> but patch "mm: mmap: merge vma after call_mmap() if possible"
> set vm_start of newly merged vma to return value addr.
> Users of mmap will get wrong address if vma is merged after call_mmap().
> We fix this by moving the assignment to addr before merging vma.
> 
> Fixes: d70cec898324 ("mm: mmap: merge vma after call_mmap() if possible")
> Signed-off-by: Liu Zixian <liuzixian4@huawei.com>
> ---
> v2:
> We want to do "addr = vma->vm_start;" unconditionally,
> so move assignment to addr before if(unlikely) block.
> ---
>  mm/mmap.c | 26 ++++++++++++--------------
>  1 file changed, 12 insertions(+), 14 deletions(-)

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>

Jason


      parent reply	other threads:[~2020-12-04 15:11 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-03  8:53 [PATCH v2] fix mmap return value when vma is merged after call_mmap() Liu Zixian
2020-12-03 22:25 ` Andrew Morton
2020-12-04  2:29   ` Liu Zixian
2020-12-04 14:11 ` David Hildenbrand
2020-12-04 15:10   ` Jason Gunthorpe
2020-12-04 15:25     ` Matthew Wilcox
2020-12-04 16:04       ` Jason Gunthorpe
2020-12-04 19:53         ` Matthew Wilcox
2020-12-04 15:11 ` Jason Gunthorpe [this message]

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