Re: + zram-pass-down-the-bvec-we-need-to-read-into-in-the-work-struct.patch added to -mm tree

[Minchan Kim <minchan@kernel.org>]

On Tue, Apr 16, 2019 at 04:53:50PM -0700, akpm@linux-foundation.org wrote:
> 
> The patch titled
>      Subject: zram: pass down the bvec we need to read into in the work struct
> has been added to the -mm tree.  Its filename is
>      zram-pass-down-the-bvec-we-need-to-read-into-in-the-work-struct.patch
> 
> This patch should soon appear at
>     http://ozlabs.org/~akpm/mmots/broken-out/zram-pass-down-the-bvec-we-need-to-read-into-in-the-work-struct.patch
> and later at
>     http://ozlabs.org/~akpm/mmotm/broken-out/zram-pass-down-the-bvec-we-need-to-read-into-in-the-work-struct.patch
> 
> Before you just go and hit "reply", please:
>    a) Consider who else should be cc'ed
>    b) Prefer to cc a suitable mailing list as well
>    c) Ideally: find the original patch on the mailing list and do a
>       reply-to-all to that, adding suitable additional cc's
> 
> *** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
> 
> The -mm tree is included into linux-next and is updated
> there every 3-4 working days
> 
> ------------------------------------------------------
> From: Jérôme Glisse <jglisse@redhat.com>
> Subject: zram: pass down the bvec we need to read into in the work struct
> 
> When scheduling work item to read page we need to pass down the proper
> bvec struct which points to the page to read into.  Before this patch it
> uses a randomly initialized bvec (only if PAGE_SIZE != 4096) which is
> wrong.
> 
> Note that without this patch on arch/kernel where PAGE_SIZE != 4096
> userspace could read random memory through a zram block device (thought
> userspace probably would have no control on the address being read).
> 
> Link: http://lkml.kernel.org/r/20190408183219.26377-1-jglisse@redhat.com
> Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
> Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
> Cc: Minchan Kim <minchan@kernel.org>
> Cc: Nitin Gupta <ngupta@vflare.org>
> Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Thanks for the nice catch, Jerome!
That sync/async read code in zram is really mess. :(

Acked-by: Minchan Kim <minchan@kernel.org>