There were a few rare cases when upon
authentication failure channel wasn't released.
This could cause stale pointers to remain in
chanctx assigned_vifs after interface removal and
trigger general protection fault later.
This could be triggered, e.g. on ath10k with the
following steps:
1. start an AP
2. create 2 extra vifs on ath10k host
3. connect vif1 to the AP
4. connect vif2 to the AP
(auth fails because ath10k firmware isn't able
to maintain 2 peers with colliding AP mac
addresses across vifs and consequently
refuses sta_info_insert() in
ieee80211_prep_connection())
5. remove the 2 extra vifs
6. goto step 2; at step 3 kernel was crashing:
general protection fault: 0000 [#1] SMP DEBUG_PAGEALLOC
Modules linked in: ath10k_pci ath10k_core ath
...
Call Trace:
[<ffffffff81a2dabb>] ieee80211_check_combinations+0x22b/0x290
[<ffffffff819fb825>] ? ieee80211_check_concurrent_iface+0x125/0x220
[<ffffffff8180f664>] ? netpoll_poll_disable+0x84/0x100
[<ffffffff819fb833>] ieee80211_check_concurrent_iface+0x133/0x220
[<ffffffff81a0029e>] ieee80211_open+0x3e/0x80
[<ffffffff817f2d26>] __dev_open+0xb6/0x130
[<ffffffff817f3051>] __dev_change_flags+0xa1/0x170
...
RIP [<ffffffff81a23140>] ieee80211_chanctx_radar_detect+0xa0/0x170
(gdb) l * ieee80211_chanctx_radar_detect+0xa0
0xffffffff81a23140 is in ieee80211_chanctx_radar_detect (/devel/src/linux/net/mac80211/util.c:3182).
3177 */
3178 WARN_ON(ctx->replace_state == IEEE80211_CHANCTX_REPLACES_OTHER &&
3179 !list_empty(&ctx->assigned_vifs));
3180
3181 list_for_each_entry(sdata, &ctx->assigned_vifs, assigned_chanctx_list)
3182 if (sdata->radar_required)
3183 radar_detect |= BIT(sdata->vif.bss_conf.chandef.width);
3184
3185 return radar_detect;
Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>