From: Paolo Abeni <pabeni@redhat.com>
To: Simon Horman <horms@kernel.org>,
Erni Sri Satya Vennela <ernis@linux.microsoft.com>
Cc: kys@microsoft.com, haiyangz@microsoft.com, wei.liu@kernel.org,
decui@microsoft.com, longli@microsoft.com, andrew+netdev@lunn.ch,
davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
shradhagupta@linux.microsoft.com, dipayanroy@linux.microsoft.com,
shirazsaleem@microsoft.com, kotaranov@microsoft.com,
yury.norov@gmail.com, kees@kernel.org,
linux-hyperv@vger.kernel.org, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH net-next] net: mana: Use at least SZ_4K in doorbell ID range check
Date: Tue, 24 Mar 2026 12:03:37 +0100 [thread overview]
Message-ID: <c8fe221f-2e1c-47a0-970f-e7a1318a15bf@redhat.com> (raw)
In-Reply-To: <20260321100425.GX74886@horms.kernel.org>
On 3/21/26 11:04 AM, Simon Horman wrote:
> On Fri, Mar 20, 2026 at 05:21:01AM -0700, Erni Sri Satya Vennela wrote:
>> mana_gd_ring_doorbell() accesses doorbell offsets up to 0xFF8 + 8 = 4KB
>> within a doorbell page. When db_page_size is zero, the validation check
>> in mana_gd_register_device() reduces to:
>> db_page_off + 0 > bar0_size
>> which passes, even though mana_gd_ring_doorbell() will access
>> [db_page_off, db_page_off + 4KB) and may go beyond BAR0.
>>
>> Use max(SZ_4K, db_page_size) in the range check so that a zero or
>> unexpectedly small db_page_size still results in a rejection when the
>> doorbell page would fall outside BAR0.
>
> Thanks Erni,
>
> I understand the maths here. And to that extent this change makes sense to me.
> But I am curious to know how a db_page_size of zero works. I was expecting
> some space is required there.
To rephrase Simon's question, this feels like papering over a
memory/state corruption. I think at best it deserves a cleaner explanation.
/P
next prev parent reply other threads:[~2026-03-24 11:03 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-20 12:21 [PATCH net-next] net: mana: Use at least SZ_4K in doorbell ID range check Erni Sri Satya Vennela
2026-03-21 10:04 ` Simon Horman
2026-03-24 11:03 ` Paolo Abeni [this message]
2026-03-25 17:35 ` Erni Sri Satya Vennela
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=c8fe221f-2e1c-47a0-970f-e7a1318a15bf@redhat.com \
--to=pabeni@redhat.com \
--cc=andrew+netdev@lunn.ch \
--cc=davem@davemloft.net \
--cc=decui@microsoft.com \
--cc=dipayanroy@linux.microsoft.com \
--cc=edumazet@google.com \
--cc=ernis@linux.microsoft.com \
--cc=haiyangz@microsoft.com \
--cc=horms@kernel.org \
--cc=kees@kernel.org \
--cc=kotaranov@microsoft.com \
--cc=kuba@kernel.org \
--cc=kys@microsoft.com \
--cc=linux-hyperv@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=longli@microsoft.com \
--cc=netdev@vger.kernel.org \
--cc=shirazsaleem@microsoft.com \
--cc=shradhagupta@linux.microsoft.com \
--cc=wei.liu@kernel.org \
--cc=yury.norov@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox