linux-kernel - Re: [PATCH 01/17] locking/lockdep: Add lock type enum to explicitly specify read or write locks

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, 13 May 2019 13:45:04 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Yuyang Du <duyuyang@...il.com>
Cc:     will.deacon@....com, mingo@...nel.org, bvanassche@....org,
        ming.lei@...hat.com, frederic@...nel.org, tglx@...utronix.de,
        boqun.feng@...il.com, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 01/17] locking/lockdep: Add lock type enum to explicitly
 specify read or write locks

On Mon, May 13, 2019 at 05:11:47PM +0800, Yuyang Du wrote:
> + * Note that we have an assumption that a lock class cannot ever be both
> + * read and recursive-read.

We have such locks in the kernel... see:

  kernel/qrwlock.c:queued_read_lock_slowpath()

And yes, that is somewhat unfortunate, but hard to get rid of due to
hysterical raisins.