Dear List,
After 2 weeks of Ferry Huberts and me trying to resolve this issue, this is the
result:
The problem can be mitigated by resetting the chip and immediately replumbing
the encryption keys. I wrote a patch for this, which unfortunately this seems
to suffer from some locking issues, rtnl_lock and sc->mutex being the chief
culprits.
Code snippet:
static void ath9k_plumb_key(struct ieee80211_hw *hw,
struct ieee80211_vif *vif,
struct ieee80211_sta *sta,
struct ieee80211_key_conf *keyconf, void *data)
{
struct ath_common *common = (struct ath_common *)data;
int ret;
/* delete and re-install keys which were programmed into the hardware */
if (vif && test_bit(keyconf->hw_key_idx, common->keymap)) {
ath_key_delete(common, keyconf);
keyconf->hw_key_idx = 0;
ret = ath_key_config(common, vif, sta, keyconf);
if (ret >= 0)
keyconf->hw_key_idx = ret;
}
}
To reset and replumb, taken from ath_reset_internal():
ath9k_hw_kill_interrupts(sc->sc_ah);
set_bit(ATH_OP_HW_RESET, &common->op_flags);
ath9k_ps_wakeup(sc);
ath_reset_internal(sc, NULL);
rtnl_lock();
ieee80211_iter_keys(sc->hw, NULL, ath9k_plumb_key, common);
rtnl_unlock();
ath9k_ps_restore(sc);
In any case, the problem is only mitigated. It is not solved, as I see the
error appearing still (less frequently though).
Looking at the OpenHAL has not yielded anything working either (there is a
reference to KEY_PLUMB_WAR, but it is not a full implementation).
What I understand from previous attempts to tackle this issue is that Qualcomm
is aware of the problem, and a workaround exists in at least the proprietary
driver. I have tried to contact Qualcomm support about this, since it is not
radio card specific, but I have not received any response so far.
I hope a Qualcomm employee reads this and is able to help obtain the
information that is necessary to resolve this issue. Until then, I recommend
using software encryption (nohwcrypt), or setting a very long rekeying time.
Kind regards,
Michel Stam
-----Original Message-----
From: ath9k-devel-boun...@lists.ath9k.org
[mailto:ath9k-devel-boun...@lists.ath9k.org] On Behalf Of Johannes Berg
Sent: Thursday, October 27, 2016 17:07 PM
To: Sebastian Gottschall; Kalle Valo; Antonio Quartulli
Cc: ath9k-de...@lists.ath9k.org; linux-wireless@vger.kernel.org; Antonio
Quartulli
Subject: Re: [ath9k-devel] [NOT FOR MERGE] ath9k: work around key cache
corruption
On Thu, 2016-10-27 at 09:54 +0200, Sebastian Gottschall wrote:
> all patches have a unclear license since most patches are not comming
> with any licence declaration ;-)
You should read the DCO some time. Maybe you shouldn't be sending
patches if you think so.
johannes
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