linux-kernel - Re: [PATCH] blk-mq: Do not lookup ctx with invalid index

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]

Date:   Mon, 14 Jun 2021 13:37:06 +0200
From:   Daniel Wagner <dwagner@...e.de>
To:     linux-block@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, Jens Axboe <axboe@...nel.dk>
Subject: Re: [PATCH] blk-mq: Do not lookup ctx with invalid index

On Tue, Jun 08, 2021 at 08:33:39PM +0200, Daniel Wagner wrote:
> cpumask_first_and() returns >= nr_cpu_ids if the two provided masks do
> not share a common bit. Verify we get a valid value back from
> cpumask_first_and().

So I got feedback on this issue (but not on the patch itself yet). The
system starts with 16 virtual CPU cores and during the test 4 cores are
removed[1] and as soon there is an error on the storage side, the reset
code on the host ends up in this path and crashes. I still don't
understand why the CPU removal is not updating the CPU mask correctly
before we hit the reset path. I'll continue to investigate.

[1] echo 0 > /sys/devices/system/cpu/cpu#/online