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From: Nathan Chancellor <natechancellor@gmail.com>
To: Dmitry Vyukov <dvyukov@google.com>
Cc: noloader@gmail.com, "Jason A. Donenfeld" <Jason@zx2c4.com>,
	Netdev <netdev@vger.kernel.org>,
	syzkaller-bugs <syzkaller-bugs@googlegroups.com>,
	WireGuard mailing list <wireguard@lists.zx2c4.com>
Subject: Re: UBSAN: object-size-mismatch in wg_xmit
Date: Fri, 8 Jan 2021 13:54:28 -0700	[thread overview]
Message-ID: <20210108205428.GA2547211@ubuntu-m3-large-x86> (raw)
In-Reply-To: <CACT4Y+ZRfQkPYoO+cgygsTLFLSbnyPRqHw3mVdVDg6zVAs4s2A@mail.gmail.com>

On Fri, Jan 08, 2021 at 10:33:19AM +0100, Dmitry Vyukov wrote:
> On Thu, Jan 7, 2021 at 8:06 PM Jeffrey Walton <noloader@gmail.com> wrote:
> >
> > On Thu, Jan 7, 2021 at 2:03 PM Jason A. Donenfeld <Jason@zx2c4.com> wrote:
> > >
> > > On Thu, Jan 7, 2021 at 1:22 PM Dmitry Vyukov <dvyukov@google.com> wrote:
> > > >
> > > > On Mon, Dec 21, 2020 at 12:23 PM Jason A. Donenfeld <Jason@zx2c4.com> wrote:
> > > > >
> > > > > ...
> > > >
> > > > These UBSAN checks were just enabled recently.
> > > > It's indeed super easy to trigger: 133083 VMs were crashed on this already:
> > > > https://syzkaller.appspot.com/bug?extid=8f90d005ab2d22342b6d
> > > > So it's one of the top crashers by now.
> > >
> > > Ahh, makes sense. So it is easily reproducible after all.
> > >
> > > You're still of the opinion that it's a false positive, right? I
> > > shouldn't spend more cycles on this?
> >
> > You might consider making a test build with -fno-lto in case LTO is
> > mucking things up.
> >
> > Google Posts Patches So The Linux Kernel Can Be LTO-Optimized By
> > Clang, https://www.phoronix.com/scan.php?page=news_item&px=Linux-Kernel-Clang-LTO-Patches
> 
> Hi Jeff,
> 
> Are these patches upstream now?
> syzbot doesn't enable LTO intentionally, nor I see CONFIG_LTO in the
> provided config.

Those patches are not upstream yet and LTO will have to be explicitly
enabled via config.

Cheers,
Nathan

  reply	other threads:[~2021-01-08 20:54 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-20 16:54 syzbot
2020-12-20 21:11 ` Jason A. Donenfeld
2020-12-21  9:14   ` Dmitry Vyukov
2020-12-21 11:23     ` Jason A. Donenfeld
2021-01-07 12:22       ` Dmitry Vyukov
2021-01-07 19:00         ` Jason A. Donenfeld
2021-01-07 19:06           ` Jeffrey Walton
2021-01-08  0:34             ` Corey Costello
2021-01-08  0:42               ` Eric Light
2021-01-08  0:44                 ` Corey Costello
2021-01-08  0:50                   ` Eric Light
2021-01-08  1:02                 ` Phillip McMahon
2021-01-08  9:33             ` Dmitry Vyukov
2021-01-08 20:54               ` Nathan Chancellor [this message]
2021-01-08  9:30           ` Dmitry Vyukov
     [not found]             ` <CAGXu5j+jzmkiU_AWoTVF6e263iYSSJYUHB=Kdqh-MCfEO-aNSg@mail.gmail.com>
2021-01-09  9:46               ` Dmitry Vyukov
2021-01-09 10:49                 ` Matthias Urlichs
2021-01-11 17:17                 ` Dmitry Vyukov
2021-01-11 17:35                   ` Jeffrey Walton
2021-01-11 17:58                     ` Dmitry Vyukov
2021-01-11 18:14                       ` Jeffrey Walton
2021-01-12  9:54                         ` Dmitry Vyukov
2021-01-07 12:53       ` Jeffrey Walton
2021-01-07 17:01       ` Julian Wiedmann
2021-01-07 18:58         ` Jason A. Donenfeld

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