From: Andrew Morton <akpm@linux-foundation.org>
To: Minchan Kim <minchan@kernel.org>
Cc: <linux-kernel@vger.kernel.org>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
<kernel-team@lge.com>, Jens Axboe <axboe@kernel.dk>,
Hannes Reinecke <hare@suse.com>,
Johannes Thumshirn <jthumshirn@suse.de>
Subject: Re: [PATCH 1/5] zram: handle multiple pages attached bio's bvec
Date: Mon, 3 Apr 2017 15:45:28 -0700 [thread overview]
Message-ID: <20170403154528.6470165dd791cf8a23ae57c8@linux-foundation.org> (raw)
In-Reply-To: <1491196653-7388-2-git-send-email-minchan@kernel.org>
On Mon, 3 Apr 2017 14:17:29 +0900 Minchan Kim <minchan@kernel.org> wrote:
> Johannes Thumshirn reported system goes the panic when using NVMe over
> Fabrics loopback target with zram.
>
> The reason is zram expects each bvec in bio contains a single page
> but nvme can attach a huge bulk of pages attached to the bio's bvec
> so that zram's index arithmetic could be wrong so that out-of-bound
> access makes panic.
>
> It can be solved by limiting max_sectors with SECTORS_PER_PAGE like
> [1] but it makes zram slow because bio should split with each pages
> so this patch makes zram aware of multiple pages in a bvec so it
> could solve without any regression.
>
> [1] 0bc315381fe9, zram: set physical queue limits to avoid array out of
> bounds accesses
This isn't a cleanup - it fixes a panic (or is it a BUG or is it an
oops, or...)
How serious is this bug? Should the fix be backported into -stable
kernels? etc.
A better description of the bug's behaviour would be appropriate.
> Cc: Jens Axboe <axboe@kernel.dk>
> Cc: Hannes Reinecke <hare@suse.com>
> Reported-by: Johannes Thumshirn <jthumshirn@suse.de>
> Tested-by: Johannes Thumshirn <jthumshirn@suse.de>
> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
> Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
> Signed-off-by: Minchan Kim <minchan@kernel.org>
This signoff trail is confusing. It somewhat implies that Johannes
authored the patch which I don't think is the case?
next prev parent reply other threads:[~2017-04-03 22:45 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-03 5:17 [PATCH 0/5] zram clean up Minchan Kim
2017-04-03 5:17 ` [PATCH 1/5] zram: handle multiple pages attached bio's bvec Minchan Kim
2017-04-03 22:45 ` Andrew Morton [this message]
2017-04-03 23:13 ` Minchan Kim
2017-04-04 4:55 ` Sergey Senozhatsky
2017-04-03 5:17 ` [PATCH 2/5] zram: partial IO refactoring Minchan Kim
2017-04-03 5:52 ` Mika Penttilä
2017-04-03 6:12 ` Minchan Kim
2017-04-03 6:57 ` Mika Penttilä
2017-04-04 2:17 ` Sergey Senozhatsky
2017-04-04 4:50 ` Minchan Kim
2017-04-03 5:17 ` [PATCH 3/5] zram: use zram_slot_lock instead of raw bit_spin_lock op Minchan Kim
2017-04-03 6:08 ` Sergey Senozhatsky
2017-04-03 6:34 ` Minchan Kim
2017-04-03 8:06 ` Sergey Senozhatsky
2017-04-04 2:18 ` Sergey Senozhatsky
2017-04-04 4:50 ` Minchan Kim
2017-04-03 5:17 ` [PATCH 4/5] zram: remove zram_meta structure Minchan Kim
2017-04-04 2:31 ` Sergey Senozhatsky
2017-04-04 4:52 ` Minchan Kim
2017-04-04 5:40 ` Minchan Kim
2017-04-04 5:54 ` Sergey Senozhatsky
2017-04-03 5:17 ` [PATCH 5/5] zram: introduce zram data accessor Minchan Kim
2017-04-04 4:40 ` Sergey Senozhatsky
2017-04-11 5:38 ` [PATCH 0/5] zram clean up Minchan Kim
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