From: "Toke Høiland-Jørgensen" <toke@redhat.com>
To: Toshiaki Makita <toshiaki.makita1@gmail.com>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
"David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <jakub.kicinski@netronome.com>,
Jesper Dangaard Brouer <hawk@kernel.org>,
John Fastabend <john.fastabend@gmail.com>
Cc: Toshiaki Makita <toshiaki.makita1@gmail.com>,
netdev@vger.kernel.org, xdp-newbies@vger.kernel.org,
bpf@vger.kernel.org, "Michael S. Tsirkin" <mst@redhat.com>,
Jason Wang <jasowang@redhat.com>, David Ahern <dsahern@gmail.com>
Subject: Re: [PATCH bpf 1/3] devmap: Fix premature entry free on destroying map
Date: Fri, 14 Jun 2019 13:04:53 +0200 [thread overview]
Message-ID: <877e9octre.fsf@toke.dk> (raw)
In-Reply-To: <20190614082015.23336-2-toshiaki.makita1@gmail.com>
Toshiaki Makita <toshiaki.makita1@gmail.com> writes:
> dev_map_free() waits for flush_needed bitmap to be empty in order to
> ensure all flush operations have completed before freeing its entries.
> However the corresponding clear_bit() was called before using the
> entries, so the entries could be used after free.
>
> All access to the entries needs to be done before clearing the bit.
> It seems commit a5e2da6e9787 ("bpf: netdev is never null in
> __dev_map_flush") accidentally changed the clear_bit() and memory access
> order.
>
> Note that the problem happens only in __dev_map_flush(), not in
> dev_map_flush_old(). dev_map_flush_old() is called only after nulling
> out the corresponding netdev_map entry, so dev_map_free() never frees
> the entry thus no such race happens there.
>
> Fixes: a5e2da6e9787 ("bpf: netdev is never null in __dev_map_flush")
> Signed-off-by: Toshiaki Makita <toshiaki.makita1@gmail.com>
I recently posted a patch[0] that gets rid of the bitmap entirely, so I
think you can drop this one...
-Toke
[0] https://lore.kernel.org/netdev/156042464148.25684.11881534392137955942.stgit@alrua-x1/
next prev parent reply other threads:[~2019-06-14 11:04 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-14 8:20 [PATCH bpf 0/3] Devmap fixes around memory and RCU Toshiaki Makita
2019-06-14 8:20 ` [PATCH bpf 1/3] devmap: Fix premature entry free on destroying map Toshiaki Makita
2019-06-14 11:04 ` Toke Høiland-Jørgensen [this message]
2019-06-14 12:10 ` Toke Høiland-Jørgensen
2019-06-14 12:59 ` Toshiaki Makita
2019-06-14 13:09 ` Toke Høiland-Jørgensen
2019-06-14 23:07 ` Daniel Borkmann
2019-06-15 10:10 ` Toke Høiland-Jørgensen
2019-06-14 12:20 ` Jesper Dangaard Brouer
2019-06-14 8:20 ` [PATCH bpf 2/3] devmap: Add missing bulk queue free Toshiaki Makita
2019-06-14 11:58 ` Jesper Dangaard Brouer
2019-06-14 13:03 ` Toshiaki Makita
2019-06-14 8:20 ` [PATCH bpf 3/3] devmap: Add missing RCU read lock on flush Toshiaki Makita
2019-06-14 11:07 ` Toke Høiland-Jørgensen
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=877e9octre.fsf@toke.dk \
--to=toke@redhat.com \
--cc=ast@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=davem@davemloft.net \
--cc=dsahern@gmail.com \
--cc=hawk@kernel.org \
--cc=jakub.kicinski@netronome.com \
--cc=jasowang@redhat.com \
--cc=john.fastabend@gmail.com \
--cc=mst@redhat.com \
--cc=netdev@vger.kernel.org \
--cc=toshiaki.makita1@gmail.com \
--cc=xdp-newbies@vger.kernel.org \
/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).