From: Linus Torvalds <torvalds@linux-foundation.org>
To: Andrii Nakryiko <andrii@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
kernel-team@fb.com,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] fs: fix NULL dereference due to data race in prepend_path()
Date: Wed, 14 Oct 2020 14:49:18 -0700 [thread overview]
Message-ID: <CAHk-=wiE04vsfJmZ-AyWJHfNdGa=WmBYt4bP3aN+sTP05=QXXA@mail.gmail.com> (raw)
In-Reply-To: <20201014204529.934574-1-andrii@kernel.org>
On Wed, Oct 14, 2020 at 2:40 PM Andrii Nakryiko <andrii@kernel.org> wrote:
>
> Fix data race in prepend_path() with re-reading mnt->mnt_ns twice without
> holding the lock. is_mounted() does check for NULL, but is_anon_ns(mnt->mnt_ns)
> might re-read the pointer again which could be NULL already, if in between
> reads one of kern_unmount()/kern_unmount_array()/umount_tree() sets mnt->mnt_ns
> to NULL.
This seems like the obviously correct fix, so I think I'll just apply
it directly.
Al? Holler if you have any issues with this..
Linus
next prev parent reply other threads:[~2020-10-15 1:29 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-14 20:45 [PATCH] fs: fix NULL dereference due to data race in prepend_path() Andrii Nakryiko
2020-10-14 21:12 ` Josef Bacik
2020-10-14 21:49 ` Linus Torvalds [this message]
2020-10-14 23:08 ` Al Viro
2020-10-14 23:12 ` Linus Torvalds
2020-10-14 23:08 ` Al Viro
2020-10-15 1:07 ` Andrii Nakryiko
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