zram: fix invalid memory references during disk write

Greg KH gregkh at linuxfoundation.org
Wed Dec 19 15:08:26 UTC 2012


On Tue, Dec 18, 2012 at 11:21:28PM -0800, Nitin Gupta wrote:
> On 12/18/2012 07:49 PM, Greg KH wrote:
> > On Tue, Dec 18, 2012 at 01:12:05PM -0800, Nitin Gupta wrote:
> >> On Tue, Dec 11, 2012 at 10:27 AM, Greg KH <gregkh at linuxfoundation.org> wrote:
> >>> On Thu, Nov 29, 2012 at 10:45:09PM -0800, Nitin Gupta wrote:
> >>>> Fixes a bug introduced by commit c8f2f0db1 ("zram: Fix handling
> >>>> of incompressible pages") which caused invalid memory references
> >>>> during disk write. Invalid references could occur in two cases:
> >>>>  - Incoming data expands on compression: In this case, reference was
> >>>> made to kunmap()'ed bio page.
> >>>>  - Partial (non PAGE_SIZE) write with incompressible data: In this
> >>>> case, reference was made to a kfree()'ed buffer.
> >>>>
> >>>> Fixes bug 50081:
> >>>> https://bugzilla.kernel.org/show_bug.cgi?id=50081
> >>>>
> >>>> Upstream commit ID: c8f2f0d: zram: Fix handling of incompressible pages
> >>>> Apply to versions: 3.6.5, 3.6.6, 3.6.7, 3.6.8
> >>>>
> >>>> Cc: <stable at vger.kernel.org> # staging-next: 37b51fd: zram: factor-out
> >>>>                               # zram_decompress_page() function
> >>>> Signed-off-by: Nitin Gupta <ngupta at vflare.org>
> >>>> Reported-by: Mihail Kasadjikov <hamer.mk at gmail.com>
> >>>> Reported-by: Tomas M <tomas at slax.org>
> >>>> Reviewed-by: Minchan Kim <minchan at kernel.org>
> >>>> ---
> >>>>  drivers/staging/zram/zram_drv.c |   39 ++++++++++++++++++++++++---------------
> >>>>  1 file changed, 24 insertions(+), 15 deletions(-)
> >>>
> >>> This patch fails to apply to 3.6.10:
> >>>
> >>> patching file drivers/staging/zram/zram_drv.c
> >>> Hunk #1 succeeded at 282 (offset 17 lines).
> >>> Hunk #2 FAILED at 286.
> >>> Hunk #3 succeeded at 319 (offset 17 lines).
> >>> Hunk #4 succeeded at 340 (offset 17 lines).
> >>> Hunk #5 succeeded at 353 (offset 17 lines).
> >>> Hunk #6 succeeded at 368 (offset 17 lines).
> >>> Hunk #7 succeeded at 385 (offset 17 lines).
> >>> 1 out of 7 hunks FAILED -- saving rejects to file drivers/staging/zram/zram_drv.c.rej
> >>>
> >>> Please redo this patch and resend it if you wish for it to be applied to
> >>> the 3.6-stable tree.
> >>>
> >>>
> >>
> >> Please apply this patch to stable tree asap.
> > 
> > 3.6 is now end-of-life, there will not be any more releases for that
> > kernel series anymore, sorry.
> > 
> 
> Then please apply to 3.7.

That is impossible to do so, for the obvious reason.

greg k-h



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