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From: Vlastimil Babka <>
To: Davidlohr Bueso <>,,
Subject: Re: [PATCH -next 0/2] ipc/shm: shmat() fixes around nil-page
Date: Thu, 10 May 2018 20:17:55 +0200
Message-ID: <> (raw)
In-Reply-To: <>

On 05/03/2018 10:32 PM, Davidlohr Bueso wrote:
> Hi,
> These patches fix two issues reported[1] a while back by Joe and Andrea
> around how shmat(2) behaves with nil-page.
> The first reverts a commit that it was incorrectly thought that mapping
> nil-page (address=0) was a no no with MAP_FIXED. This is not the case,
> with the exception of SHM_REMAP; which is address in the second patch.

Can you add appropriate Fixes: tags if possible? I guess patch 1 is
clear, dunno about patch 2...

> I chose two patches because it is easier to backport and it explicitly
> reverts bogus behaviour. Both patches ought to be in -stable and ltp
> testcases need updated (the added testcase around the cve can be modified
> to just test for SHM_RND|SHM_REMAP).

CC'd ltp so they know :)


> [1]
> Thanks! 
> Davidlohr Bueso (2):
>   Revert "ipc/shm: Fix shmat mmap nil-page protection"
>   ipc/shm: fix shmat() nil address after round-down when remapping
>  ipc/shm.c | 19 +++++++++++--------
>  1 file changed, 11 insertions(+), 8 deletions(-)

  parent reply index

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-03 20:32 Davidlohr Bueso
2018-05-03 20:32 ` [PATCH 1/2] Revert "ipc/shm: Fix shmat mmap nil-page protection" Davidlohr Bueso
2018-05-03 20:49 ` [PATCH 2/2] ipc/shm: fix shmat() nil address after round-down when remapping Davidlohr Bueso
2018-05-10 18:17 ` Vlastimil Babka [this message]
2018-05-14 16:19   ` [PATCH -next 0/2] ipc/shm: shmat() fixes around nil-page Davidlohr Bueso

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