Brian reported several issues with zram's writeback implementation.
This small series addresses those issues.

Sergey Senozhatsky (2):
  zram: do not leak blk idx at the end of writeback
  zram: clear trailing bytes of compressed writeback pages

 drivers/block/zram/zram_drv.c | 5 +++++
 1 file changed, 5 insertions(+)

-- 
2.54.0.746.g67dd491aae-goog

On Mon, 25 May 2026 13:46:00 +0900 Sergey Senozhatsky <senozhatsky@chromium.org> wrote:

> Brian reported several issues with zram's writeback implementation.
> This small series addresses those issues.

I hate to go all bureaucratic, but there's quite a lot missing here,
and it's rather important, to some.  It's all about taking care of
people who are using kernels prior to 7.2 (or 7.1).

- Link: to Brian's reports?

- Description of user-visible runtime effects of the bugs?

- Fixes: targets?

- Decision on whether we should backport the fixes into earlier kernels?

Anyway, I'll queue these in mm-new, but please give some thought to the
above?

Also, AI review didn't find anything to complain about with these
changes, but it might have found a pre-existing issue:

	https://sashiko.dev/#/patchset/20260525044639.1888561-1-senozhatsky@chromium.org

Thanks.

On (26/05/25 14:31), Andrew Morton wrote:
> > Brian reported several issues with zram's writeback implementation.
> > This small series addresses those issues.
> 
> I hate to go all bureaucratic, but there's quite a lot missing here,
> and it's rather important, to some.  It's all about taking care of
> people who are using kernels prior to 7.2 (or 7.1).

Sorry, Andrew, it was just me being lazy.

> - Link: to Brian's reports?
> 
> - Description of user-visible runtime effects of the bugs?
> 
> - Fixes: targets?
> 
> - Decision on whether we should backport the fixes into earlier kernels?

I updated commit messages and sent out v2.  The reports are private,
so on public links.  Both issues are low risk.

[..]

> Also, AI review didn't find anything to complain about with these
> changes, but it might have found a pre-existing issue:
> 
> 	https://sashiko.dev/#/patchset/20260525044639.1888561-1-senozhatsky@chromium.org

Correct, a pre-existing issue (first appeared in v6.19), we fix it in this
series.  The theoretical data leak issue first appeared in v7.0.