bpf.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: "Toke Høiland-Jørgensen" <toke@redhat.com>
To: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: daniel@iogearbox.net, ast@fb.com, bpf@vger.kernel.org,
	netdev@vger.kernel.org
Subject: Re: [PATCH bpf] xdp: Handle device unregister for devmap_hash map type
Date: Thu, 17 Oct 2019 12:28:05 +0200	[thread overview]
Message-ID: <87ftjrfyyy.fsf@toke.dk> (raw)
In-Reply-To: <2d516208-8c46-707c-4484-4547e66fc128@i-love.sakura.ne.jp>

Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> writes:

> On 2019/10/16 22:28, Toke Høiland-Jørgensen wrote:
>> It seems I forgot to add handling of devmap_hash type maps to the device
>> unregister hook for devmaps. This omission causes devices to not be
>> properly released, which causes hangs.
>> 
>> Fix this by adding the missing handler.
>> 
>> Fixes: 6f9d451ab1a3 ("xdp: Add devmap_hash map type for looking up devices by hashed index")
>> Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
>> Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
>
> Well, regarding 6f9d451ab1a3, I think that we want explicit "(u64)" cast
>
> @@ -97,6 +123,14 @@ static int dev_map_init_map(struct bpf_dtab *dtab, union bpf_attr *attr)
>         cost = (u64) dtab->map.max_entries * sizeof(struct bpf_dtab_netdev *);
>         cost += sizeof(struct list_head) * num_possible_cpus();
>
> +       if (attr->map_type == BPF_MAP_TYPE_DEVMAP_HASH) {
> +               dtab->n_buckets = roundup_pow_of_two(dtab->map.max_entries);
> +
> +               if (!dtab->n_buckets) /* Overflow check */
> +                       return -EINVAL;
> +               cost += sizeof(struct hlist_head) * dtab->n_buckets;
>
>                                                     ^here
>
> +       }
> +
>         /* if map size is larger than memlock limit, reject it */
>         err = bpf_map_charge_init(&dtab->map.memory, cost);
>         if (err)
>
> like "(u64) dtab->map.max_entries * sizeof(struct bpf_dtab_netdev *)" does.
> Otherwise, on 32bits build, "sizeof(struct hlist_head) * dtab->n_buckets" can become 0.

Oh, right. I kinda assumed the compiler would be smart enough to figure
that out based on the type of the LHS; will send a separate fix for this.

-Toke


  reply	other threads:[~2019-10-17 10:28 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-16 13:28 Toke Høiland-Jørgensen
2019-10-16 16:24 ` Martin Lau
2019-10-17 10:27   ` Toke Høiland-Jørgensen
2019-10-16 20:09 ` Tetsuo Handa
2019-10-17 10:28   ` Toke Høiland-Jørgensen [this message]
2019-10-17 15:23     ` Alexei Starovoitov
2019-10-17 15:40       ` Toke Høiland-Jørgensen
2019-10-17 19:17 ` Andrii Nakryiko
2019-10-18 10:31   ` Toke Høiland-Jørgensen
2019-10-18 16:28     ` Andrii Nakryiko

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=87ftjrfyyy.fsf@toke.dk \
    --to=toke@redhat.com \
    --cc=ast@fb.com \
    --cc=bpf@vger.kernel.org \
    --cc=daniel@iogearbox.net \
    --cc=netdev@vger.kernel.org \
    --cc=penguin-kernel@i-love.sakura.ne.jp \
    --subject='Re: [PATCH bpf] xdp: Handle device unregister for devmap_hash map type' \
    /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

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).