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From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Sun, 8 Dec 2019 19:10:23 -0800
Message-ID: <CAHk-=whY0GL-FpnjUmc7fjDqz-yRJ=QBO7LT6aEzt-_raAb1bw@mail.gmail.com>
Subject: Re: refcount_t: underflow; use-after-free with CIFS umount after
 scsi-misc commit ef2cc88e2a205b8a11a19e78db63a70d3728cdf5
To:     Al Viro <viro@zeniv.linux.org.uk>
Cc:     Arthur Marsh <arthur.marsh@internode.on.net>,
        SCSI development list <linux-scsi@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        CIFS <linux-cifs@vger.kernel.org>,
        "James E.J. Bottomley" <jejb@linux.ibm.com>
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On Sun, Dec 8, 2019 at 6:52 PM Al Viro <viro@zeniv.linux.org.uk> wrote:
>
> FWIW, the thing that is IME absolutely incompatible with bisection
> is CONFIG_GCC_PLUGIN_RANDSTRUCT.  It can affect frequencies badly
> enough, even in the cases when the bug isn't directly dependent
> upon that thing.

It will easily affect timing in major ways, yes.

You're right that at least the CI bots might want to disable it for
bisecting. Or force a particular seed for RANDSTRUCT - I seem to
recall that there was some way to make it be at least repeatable for
any particular structure.

         Linus