netdev - Re: general protection fault in in

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Message-ID: <CA+55aFz1GVHUGiX1SE_5C-e9LdXdx3pBB10zwga1LOy6axk5Ww@mail.gmail.com>
Date:   Tue, 10 Jul 2018 13:15:02 -0700
From:   Linus Torvalds <torvalds@...ux-foundation.org>
To:     Dmitry Vyukov <dvyukov@...gle.com>
Cc:     syzbot+2a831e062bb4aebd8755@...kaller.appspotmail.com,
        Eric Van Hensbergen <ericvh@...il.com>,
        Ron Minnich <rminnich@...dia.gov>,
        Latchesar Ionkov <lucho@...kov.net>,
        Jens Axboe <axboe@...nel.dk>,
        Bart Van Assche <bart.vanassche@....com>,
        David Miller <davem@...emloft.net>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Network Development <netdev@...r.kernel.org>,
        Sagi Grimberg <sagi@...mberg.me>,
        syzkaller-bugs@...glegroups.com,
        kasan-dev <kasan-dev@...glegroups.com>
Subject: Re: general protection fault in in_aton

On Tue, Jul 10, 2018 at 12:57 PM Dmitry Vyukov <dvyukov@...gle.com> wrote:
>
> Is it really hard to get fault address? I know that userspace
> generally receives fault address in siginfo.

For an actual page fault it's trivial.

However, for invalid addresses (aka "non-canonical"), you don't even
get a page fault, you get a GP like in this case. And then the actual
address is not available.

                 Linus