From: "Toke Høiland-Jørgensen" <toke@redhat.com>
To: make-wifi-fast@lists.bufferbloat.net, linux-wireless@vger.kernel.org
Subject: Re: [PATCH bpf-next] xdp: Fix race in dev_map_hash_update_elem() when replacing element
Date: Sun, 08 Sep 2019 09:33:51 +0100 [thread overview]
Message-ID: <87sgp7w5jk.fsf@toke.dk> (raw)
In-Reply-To: <20190908082016.17214-1-toke@redhat.com>
Toke Høiland-Jørgensen <toke@redhat.com> writes:
> syzbot found a crash in dev_map_hash_update_elem(), when replacing an
> element with a new one. Jesper correctly identified the cause of the crash
> as a race condition between the initial lookup in the map (which is done
> before taking the lock), and the removal of the old element.
>
> Rather than just add a second lookup into the hashmap after taking the
> lock, fix this by reworking the function logic to take the lock before the
> initial lookup.
>
> Fixes: 6f9d451ab1a3 ("xdp: Add devmap_hash map type for looking up devices by hashed index")
> Reported-and-tested-by: syzbot+4e7a85b1432052e8d6f8@syzkaller.appspotmail.com
> Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
> ---
Oops, this wasn't supposed to go to linux-wireless and make-wifi-fast;
apologies for the noise! :)
-Toke
prev parent reply other threads:[~2019-09-08 8:33 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <0000000000005091a70591d3e1d9@google.com>
2019-09-08 8:20 ` [PATCH bpf-next] xdp: Fix race in dev_map_hash_update_elem() when replacing element Toke Høiland-Jørgensen
2019-09-08 8:33 ` Toke Høiland-Jørgensen [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=87sgp7w5jk.fsf@toke.dk \
--to=toke@redhat.com \
--cc=linux-wireless@vger.kernel.org \
--cc=make-wifi-fast@lists.bufferbloat.net \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).