Re: fs: NULL deref in atime_needs_update

From	Al Viro <viro@ZenIV.linux.org.uk>
Newsgroups	linux.kernel
Subject	Re: fs: NULL deref in atime_needs_update
Date	2016-02-22 18:30 +0100
Message-ID	<r52t3-LR-9@gated-at.bofh.it> (permalink)
References	(3 earlier) <r46p3-7fD-1@gated-at.bofh.it> <r46S6-7qj-5@gated-at.bofh.it> <r4i6S-7Jo-19@gated-at.bofh.it> <r4jmi-xc-15@gated-at.bofh.it> <r4WQG-51k-7@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Mon, Feb 22, 2016 at 12:20:30PM +0100, Dmitry Vyukov wrote:

> I've reproduced the second report (the one originating in openat) with
> this patch and the WARNING did _not_ fire:

Lovely...  Could you dump your inode.o on anonftp somewhere?  Or post
the disassembled atime_needs_update, for that matter - shouldn't be
all that long...  .config (and gcc version) you are using would also be nice.

On the face of it, NULL inode is a plausible source of that one, but
it's _very_ odd.  It would have to be NULL ->link_inode, and since the
warning hadn't triggered, there was a successful should_follow_link(),
with NULL inode argument.

	Could you slap WARN_ON(!inode) in pick_link()?  Or even
WARN_ON(IS_ERR_OR_NULL(inode)), for that matter...

Thread

Re: fs: NULL deref in atime_needs_update Mickaël Salaün <mic@digikod.net> - 2016-02-17 02:00 +0100
  Re: fs: NULL deref in atime_needs_update Dmitry Vyukov <dvyukov@google.com> - 2016-02-19 20:40 +0100
    Re: fs: NULL deref in atime_needs_update Al Viro <viro@ZenIV.linux.org.uk> - 2016-02-20 04:30 +0100
      Re: fs: NULL deref in atime_needs_update Al Viro <viro@ZenIV.linux.org.uk> - 2016-02-20 05:00 +0100
        Re: fs: NULL deref in atime_needs_update Mickaël Salaün <mic@digikod.net> - 2016-02-20 17:00 +0100
          Re: fs: NULL deref in atime_needs_update Al Viro <viro@ZenIV.linux.org.uk> - 2016-02-20 18:20 +0100
            Re: fs: NULL deref in atime_needs_update Al Viro <viro@ZenIV.linux.org.uk> - 2016-02-20 22:00 +0100
            Re: fs: NULL deref in atime_needs_update Mickaël Salaün <mic@digikod.net> - 2016-02-20 22:10 +0100
            Re: fs: NULL deref in atime_needs_update Dmitry Vyukov <dvyukov@google.com> - 2016-02-22 12:30 +0100
              Re: fs: NULL deref in atime_needs_update Al Viro <viro@ZenIV.linux.org.uk> - 2016-02-22 18:30 +0100
                Re: fs: NULL deref in atime_needs_update Dmitry Vyukov <dvyukov@google.com> - 2016-02-23 16:40 +0100
                Re: fs: NULL deref in atime_needs_update Al Viro <viro@ZenIV.linux.org.uk> - 2016-02-23 19:20 +0100
      Re: fs: NULL deref in atime_needs_update Dmitry Vyukov <dvyukov@google.com> - 2016-02-20 11:40 +0100
  Re: fs: NULL deref in atime_needs_update Ian Kent <raven@themaw.net> - 2016-02-24 04:20 +0100
    Re: fs: NULL deref in atime_needs_update Al Viro <viro@ZenIV.linux.org.uk> - 2016-02-24 05:50 +0100
      Re: fs: NULL deref in atime_needs_update Dmitry Vyukov <dvyukov@google.com> - 2016-02-24 11:10 +0100
        Re: fs: NULL deref in atime_needs_update Dmitry Vyukov <dvyukov@google.com> - 2016-02-24 11:20 +0100
          Re: fs: NULL deref in atime_needs_update Dmitry Vyukov <dvyukov@google.com> - 2016-02-24 14:40 +0100
            Re: fs: NULL deref in atime_needs_update Al Viro <viro@ZenIV.linux.org.uk> - 2016-02-24 16:20 +0100
              Re: fs: NULL deref in atime_needs_update Dmitry Vyukov <dvyukov@google.com> - 2016-02-25 09:30 +0100
                Re: fs: NULL deref in atime_needs_update Al Viro <viro@ZenIV.linux.org.uk> - 2016-02-25 17:40 +0100
                Re: fs: NULL deref in atime_needs_update Dmitry Vyukov <dvyukov@google.com> - 2016-02-26 22:30 +0100
                Re: fs: NULL deref in atime_needs_update Al Viro <viro@ZenIV.linux.org.uk> - 2016-02-26 23:10 +0100
                Re: fs: NULL deref in atime_needs_update Al Viro <viro@ZenIV.linux.org.uk> - 2016-02-27 23:30 +0100
                Re: fs: NULL deref in atime_needs_update Dmitry Vyukov <dvyukov@google.com> - 2016-02-28 17:10 +0100
                Re: fs: NULL deref in atime_needs_update Al Viro <viro@ZenIV.linux.org.uk> - 2016-02-28 18:10 +0100
                Re: fs: NULL deref in atime_needs_update Al Viro <viro@ZenIV.linux.org.uk> - 2016-02-28 21:10 +0100
                Re: fs: NULL deref in atime_needs_update Dmitry Vyukov <dvyukov@google.com> - 2016-02-29 10:40 +0100
                Re: fs: NULL deref in atime_needs_update Dmitry Vyukov <dvyukov@google.com> - 2016-02-29 13:40 +0100
                Re: fs: NULL deref in atime_needs_update Al Viro <viro@ZenIV.linux.org.uk> - 2016-02-29 17:20 +0100
                Re: fs: NULL deref in atime_needs_update Al Viro <viro@ZenIV.linux.org.uk> - 2016-02-29 14:10 +0100
                Re: fs: NULL deref in atime_needs_update David Howells <dhowells@redhat.com> - 2016-02-29 14:50 +0100
                Re: fs: NULL deref in atime_needs_update Dmitry Vyukov <dvyukov@google.com> - 2016-02-29 17:00 +0100
                Re: fs: NULL deref in atime_needs_update Al Viro <viro@ZenIV.linux.org.uk> - 2016-02-29 17:30 +0100
                Re: fs: NULL deref in atime_needs_update Dmitry Vyukov <dvyukov@google.com> - 2016-02-29 19:30 +0100
                Re: fs: NULL deref in atime_needs_update Dmitry Vyukov <dvyukov@google.com> - 2016-03-01 10:00 +0100
                Re: fs: NULL deref in atime_needs_update Linus Torvalds <torvalds@linux-foundation.org> - 2016-02-29 17:50 +0100
                Re: fs: NULL deref in atime_needs_update Al Viro <viro@ZenIV.linux.org.uk> - 2016-02-29 18:00 +0100
                Re: fs: NULL deref in atime_needs_update Al Viro <viro@ZenIV.linux.org.uk> - 2016-02-29 18:30 +0100
                Re: fs: NULL deref in atime_needs_update Linus Torvalds <torvalds@linux-foundation.org> - 2016-02-29 18:30 +0100
                Re: fs: NULL deref in atime_needs_update Al Viro <viro@ZenIV.linux.org.uk> - 2016-02-26 22:30 +0100

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