From 416fbdff2137e8d8cc8f23f517bee3a26b11526f Mon Sep 17 00:00:00 2001 From: "Luis R. Rodriguez" Date: Tue, 11 Aug 2009 13:10:33 -0700 Subject: [PATCH] mac80211: fix panic when splicing unprepared TIDs We splice skbs from the pending queue for a TID onto the local pending queue when tearing down a block ack request. This is not necessary unless we actually have received a request to start a block ack request (rate control, for example). If we never received that request we should not be splicing the tid pending queue as it would be null, causing a panic. Not sure yet how exactly we allowed through a call when the tid state does not have at least HT_ADDBA_REQUESTED_MSK set, that will require some further review as it is not quite obvious. For more information see the bug report: http://bugzilla.kernel.org/show_bug.cgi?id=13922 This fixes this oops: BUG: unable to handle kernel NULL pointer dereference at 00000030 IP: [] ieee80211_agg_splice_packets+0x40/0xc0 [mac80211] *pdpt = 0000000002d1e001 *pde = 0000000000000000 Thread overran stack, or stack corrupted Oops: 0000 [#1] SMP last sysfs file: /sys/module/aes_generic/initstate Modules linked in: Pid: 0, comm: swapper Not tainted (2.6.31-rc5-wl #2) Dell DV051 EIP: 0060:[] EFLAGS: 00010292 CPU: 0 EIP is at ieee80211_agg_splice_packets+0x40/0xc0 [mac80211] EAX: 00000030 EBX: 0000004c ECX: 00000003 EDX: 00000000 ESI: c1c98000 EDI: f745a1c0 EBP: c076be58 ESP: c076be38 DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068 Process swapper (pid: 0, ti=c076a000 task=c0709160 task.ti=c076a000) Stack: Call Trace: [] ? ieee80211_stop_tx_ba_cb+0xab/0x150 [mac80211] [] ? ieee80211_tasklet_handler+0xce/0x110 [mac80211] [] ? net_rx_action+0xef/0x1d0 [] ? tasklet_action+0x58/0xc0 [] ? __do_softirq+0xc2/0x190 [] ? handle_IRQ_event+0x58/0x140 [] ? ack_apic_level+0x7e/0x270 [] ? do_softirq+0x3d/0x40 [] ? irq_exit+0x65/0x90 [] ? do_IRQ+0x4f/0xc0 [] ? irq_exit+0x7d/0x90 [] ? smp_apic_timer_interrupt+0x57/0x90 [] ? common_interrupt+0x29/0x30 [] ? mwait_idle+0xbe/0x100 [] ? cpu_idle+0x52/0x90 [] ? rest_init+0x55/0x60 [] ? start_kernel+0x315/0x37d [] ? unknown_bootoption+0x0/0x1f9 [] ? i386_start_kernel+0x79/0x81 Code: EIP: [] ieee80211_agg_splice_packets+0x40/0xc0 [mac80211] SS:ESP 0068:c076be38 CR2: 0000000000000030 Cc: stable@kernel.org Testedy-by: Jack Lau Signed-off-by: Luis R. Rodriguez Signed-off-by: John W. Linville --- net/mac80211/agg-tx.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/net/mac80211/agg-tx.c b/net/mac80211/agg-tx.c index 9e5762a..a24e598 100644 --- a/net/mac80211/agg-tx.c +++ b/net/mac80211/agg-tx.c @@ -381,6 +381,14 @@ static void ieee80211_agg_splice_packets(struct ieee80211_local *local, &local->hw, queue, IEEE80211_QUEUE_STOP_REASON_AGGREGATION); + if (!(sta->ampdu_mlme.tid_state_tx[tid] & HT_ADDBA_REQUESTED_MSK)) + return; + + if (WARN(!sta->ampdu_mlme.tid_tx[tid], + "TID %d gone but expected when splicing aggregates from" + "the pending queue\n", tid)) + return; + if (!skb_queue_empty(&sta->ampdu_mlme.tid_tx[tid]->pending)) { spin_lock_irqsave(&local->queue_stop_reason_lock, flags); /* mark queue as pending, it is stopped already */ -- 2.7.4