linux-kernel - double call identical release when there is a race hitting

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-next>] [day] [month] [year] [list]

Date:   Tue, 6 Jun 2017 21:39:36 +0800
From:   zhong jiang <zhongjiang@...wei.com>
To:     Michal Hocko <mhocko@...nel.org>, Vlastimil Babka <vbabka@...e.cz>,
        "David Rientjes" <rientjes@...gle.com>,
        Hugh Dickins <hughd@...gle.com>,
        "Oleg Nesterov" <oleg@...hat.com>
CC:     Linux Memory Management List <linux-mm@...ck.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Xishi Qiu <qiuxishi@...wei.com>
Subject: double call identical release when there is a race hitting

Hi

when I review the code, I find the following scenario will lead to a race ,
but I am not sure whether the real issue will hit or not.

cpu1                                                                      cpu2
exit_mmap                                               mmu_notifier_unregister
   __mmu_notifier_release                                 srcu_read_lock
            srcu_read_lock
            mm->ops->release(mn, mm)                 mm->ops->release(mn,mm)
           srcu_read_unlock                                         srcu_read_unlock


obviously,  the specified mm will call identical release function when
the related condition satisfy.  is it right?

Thanks
zhongjiang