linux-kernel - Re: [Drbd-dev] [PATCH 2/2] drbd: remove check of list iterator against head past the loop body

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <078e8084-8fea-5b69-89a6-9488a28163cf@kernel.dk>
Date:   Thu, 31 Mar 2022 17:09:51 -0600
From:   Jens Axboe <axboe@...nel.dk>
To:     Christoph Böhmwalder 
        <christoph.boehmwalder@...bit.com>,
        Jakob Koschel <jakobkoschel@...il.com>
Cc:     linux-kernel@...r.kernel.org, "Bos, H.J." <h.j.bos@...nl>,
        Brian Johannesmeyer <bjohannesmeyer@...il.com>,
        linux-block@...r.kernel.org,
        Cristiano Giuffrida <c.giuffrida@...nl>,
        Lars Ellenberg <lars.ellenberg@...bit.com>,
        Mike Rapoport <rppt@...nel.org>, drbd-dev@...ts.linbit.com,
        Philipp Reisner <philipp.reisner@...bit.com>
Subject: Re: [Drbd-dev] [PATCH 2/2] drbd: remove check of list iterator
 against head past the loop body

On 3/31/22 4:28 PM, Christoph B?hmwalder wrote:
> Am 01.04.22 um 00:03 schrieb Jakob Koschel:
>> When list_for_each_entry() completes the iteration over the whole list
>> without breaking the loop, the iterator value will be a bogus pointer
>> computed based on the head element.
>>
>> While it is safe to use the pointer to determine if it was computed
>> based on the head element, either with list_entry_is_head() or
>> &pos->member == head, using the iterator variable after the loop should
>> be avoided.
>>
>> In preparation to limit the scope of a list iterator to the list
>> traversal loop, use a dedicated pointer to point to the found element [1].
>>
> 
> Hi Jakob,
> 
> Both of these look good to me, thanks.
> 
> Reviewed-by: Christoph B?hmwalder <christoph.boehmwalder@...bit.com>

Applied both, but shortened title of this commit. Jakob, please keep it
within the usual 74 chars. In general, it's great to use a cover letter
for anything that's more than one patch. Just some pointers if you're
doing more of these.

-- 
Jens Axboe