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Re: [mac80211] BUG_ON with current -git (4.8.0-11417-g24532f7)

From Ard Biesheuvel <ard.biesheuvel@linaro.org>
Newsgroups linux.kernel
Subject Re: [mac80211] BUG_ON with current -git (4.8.0-11417-g24532f7)
Date 2016-10-14 11:40 +0200
Message-ID <ss785-7U4-5@gated-at.bofh.it> (permalink)
References (16 earlier) <ss6vo-7rk-15@gated-at.bofh.it> <ss6F3-7JP-3@gated-at.bofh.it> <ss6OK-7Nf-11@gated-at.bofh.it> <ss6Yp-7QI-25@gated-at.bofh.it> <ss6Yp-7QI-23@gated-at.bofh.it>
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On 14 October 2016 at 10:25, Johannes Berg <johannes@sipsolutions.net> wrote:
> On Fri, 2016-10-14 at 10:21 +0100, Ard Biesheuvel wrote:
>
>> It is annotated with a TODO, though :-)
>>
>> 38320c70d282b (Herbert Xu               2008-01-28 19:35:05
>> -0800  41)
>>  * TODO: Use spare space in skb for this where possible.
>
> I saw that, but I don't think generally there will be spare space for
> it - the stuff there is likely far too big. Anyway ... same problem
> that we have.
>
> I'm not inclined to allocate ~500 bytes temporarily for every frame
> either though.
>
> Maybe we could try to manage it in mac80211, we'd "only" need 5 AEAD
> structs (which are today on the stack) in parallel for each key (4 TX,
> 1 RX), but in a typical case of having 3 keys that's already 7.5K worth
> of memory that we almost never use. Again, with more complexity, we
> could know that the TX will not be used if the driver does the TX, but
> the single RX one we'd need unconditionally... decisions decisions...
>

So why is the performance hit acceptable for ESP but not for WPA? We
could easily implement the same thing, i.e., kmalloc(GFP_ATOMIC)/kfree
the aead_req struct rather than allocate it on the stack

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Re: [mac80211] BUG_ON with current -git (4.8.0-11417-g24532f7) Andy Lutomirski <luto@amacapital.net> - 2016-10-13 08:10 +0200
  Re: [mac80211] BUG_ON with current -git (4.8.0-11417-g24532f7) Johannes Berg <johannes@sipsolutions.net> - 2016-10-13 08:10 +0200
    Re: [mac80211] BUG_ON with current -git (4.8.0-11417-g24532f7) Sergey Senozhatsky <sergey.senozhatsky@gmail.com> - 2016-10-13 15:50 +0200
      Re: [mac80211] BUG_ON with current -git (4.8.0-11417-g24532f7) Sergey Senozhatsky <sergey.senozhatsky@gmail.com> - 2016-10-13 16:10 +0200
      Re: [mac80211] BUG_ON with current -git (4.8.0-11417-g24532f7) Johannes Berg <johannes@sipsolutions.net> - 2016-10-13 16:20 +0200
        Re: [mac80211] BUG_ON with current -git (4.8.0-11417-g24532f7) Sergey Senozhatsky <sergey.senozhatsky@gmail.com> - 2016-10-13 17:10 +0200
          Re: [mac80211] BUG_ON with current -git (4.8.0-11417-g24532f7) Sergey Senozhatsky <sergey.senozhatsky@gmail.com> - 2016-10-13 17:30 +0200
        Re: [mac80211] BUG_ON with current -git (4.8.0-11417-g24532f7) Andy Lutomirski <luto@amacapital.net> - 2016-10-14 00:00 +0200
          Re: [mac80211] BUG_ON with current -git (4.8.0-11417-g24532f7) Johannes Berg <johannes@sipsolutions.net> - 2016-10-14 09:30 +0200
            Re: [mac80211] BUG_ON with current -git (4.8.0-11417-g24532f7) Johannes Berg <johannes@sipsolutions.net> - 2016-10-14 10:30 +0200
              Re: [mac80211] BUG_ON with current -git (4.8.0-11417-g24532f7) Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2016-10-14 10:40 +0200
                Re: [mac80211] BUG_ON with current -git (4.8.0-11417-g24532f7) Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2016-10-14 10:50 +0200
                Re: [mac80211] BUG_ON with current -git (4.8.0-11417-g24532f7) Johannes Berg <johannes@sipsolutions.net> - 2016-10-14 11:00 +0200
                Re: [mac80211] BUG_ON with current -git (4.8.0-11417-g24532f7) Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2016-10-14 11:10 +0200
                Re: [mac80211] BUG_ON with current -git (4.8.0-11417-g24532f7) Johannes Berg <johannes@sipsolutions.net> - 2016-10-14 11:20 +0200
                Re: [mac80211] BUG_ON with current -git (4.8.0-11417-g24532f7) Johannes Berg <johannes@sipsolutions.net> - 2016-10-14 11:30 +0200
                Re: [mac80211] BUG_ON with current -git (4.8.0-11417-g24532f7) Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2016-10-14 11:40 +0200
                Re: [mac80211] BUG_ON with current -git (4.8.0-11417-g24532f7) Johannes Berg <johannes@sipsolutions.net> - 2016-10-14 12:10 +0200
                Re: [mac80211] BUG_ON with current -git (4.8.0-11417-g24532f7) Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2016-10-14 13:20 +0200
                Re: [mac80211] BUG_ON with current -git (4.8.0-11417-g24532f7) Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2016-10-14 11:30 +0200
                Re: [mac80211] BUG_ON with current -git (4.8.0-11417-g24532f7) Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2016-10-14 10:50 +0200
                Re: [mac80211] BUG_ON with current -git (4.8.0-11417-g24532f7) Johannes Berg <johannes@sipsolutions.net> - 2016-10-14 10:50 +0200
            Re: [mac80211] BUG_ON with current -git (4.8.0-11417-g24532f7) Johannes Berg <johannes@sipsolutions.net> - 2016-10-14 11:00 +0200
          Re: [mac80211] BUG_ON with current -git (4.8.0-11417-g24532f7) Johannes Berg <johannes@sipsolutions.net> - 2016-10-14 10:50 +0200
          Re: [mac80211] BUG_ON with current -git (4.8.0-11417-g24532f7) Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2016-10-14 10:50 +0200

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