linux-kernel - Re: BUG_ON hit in "reimplement path_mountpoint() with less magic" [Was: Re: linux-next: Tree for Jan 13]

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Message-ID: <CAHmME9rBb5Otr-96W38kNjXkfok9NwFJ6V263qoPTJHqNEsgoA@mail.gmail.com>
Date:   Mon, 13 Jan 2020 14:33:31 -0500
From:   "Jason A. Donenfeld" <Jason@...c4.com>
To:     Al Viro <viro@...iv.linux.org.uk>
Cc:     Stephen Rothwell <sfr@...b.auug.org.au>,
        Linux Next Mailing List <linux-next@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: BUG_ON hit in "reimplement path_mountpoint() with less magic"
 [Was: Re: linux-next: Tree for Jan 13]

Hey Al,

On Mon, Jan 13, 2020 at 2:23 PM Al Viro <viro@...iv.linux.org.uk> wrote:
>
> On Mon, Jan 13, 2020 at 01:27:34PM -0500, Jason A. Donenfeld wrote:
> > Hi Al,
> >
> > Your "reimplement path_mountpoint() with less magic" commit is causing
> > oopses on the linux-next tests running on https://build.wireguard.com/ .
> > Here's one such crash with debug symbols:
>
> Check if that persists with the version currently in #fixes (commit
> 7a955b7363b8).  It ought to be fixed there; quick check is to look
> at fs/namei.c:path_mountpoint() in your tree - it should read
>         if (!err && (nd->flags & LOOKUP_RCU))
>                 err = unlazy_walk(nd);
> not
>         if (!err)
>                 err = unlazy_walk(nd);
> as in the broken variant.

That does the trick. Glad that's sorted. Thanks.

Jason