From 4b1bfb7d2d125af6653d6c2305356b2677f79dc6 Mon Sep 17 00:00:00 2001 From: Stanislaw Gruszka Date: Wed, 10 Aug 2011 15:32:22 +0200 Subject: [PATCH] rt2x00: fix crash in rt2800usb_write_tx_desc Patch should fix this oops: BUG: unable to handle kernel NULL pointer dereference at 000000a0 IP: [] rt2800usb_write_tx_desc+0x18/0xc0 [rt2800usb] *pdpt = 000000002408c001 *pde = 0000000024079067 *pte = 0000000000000000 Oops: 0000 [#1] SMP EIP: 0060:[] EFLAGS: 00010282 CPU: 0 EIP is at rt2800usb_write_tx_desc+0x18/0xc0 [rt2800usb] EAX: 00000035 EBX: ef2bef10 ECX: 00000000 EDX: d40958a0 ESI: ef1865f8 EDI: ef1865f8 EBP: d4095878 ESP: d409585c DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 Call Trace: [] rt2x00queue_write_tx_frame+0x155/0x300 [rt2x00lib] [] rt2x00mac_tx+0x7c/0x370 [rt2x00lib] [] ? mark_held_locks+0x62/0x90 [] ? _raw_spin_unlock_irqrestore+0x35/0x60 [] ? trace_hardirqs_on_caller+0x5a/0x170 [] ? trace_hardirqs_on+0xb/0x10 [] __ieee80211_tx+0x5c/0x1e0 [mac80211] [] ieee80211_tx+0xbc/0xe0 [mac80211] [] ? ieee80211_tx+0x23/0xe0 [mac80211] [] ieee80211_xmit+0xc1/0x200 [mac80211] [] ? ieee80211_tx+0xe0/0xe0 [mac80211] [] ? lock_release_holdtime+0x35/0x1b0 [] ? ieee80211_subif_start_xmit+0x446/0x5f0 [mac80211] [] ieee80211_subif_start_xmit+0x29d/0x5f0 [mac80211] [] ? ieee80211_subif_start_xmit+0x3e4/0x5f0 [mac80211] [] ? sock_setsockopt+0x6a8/0x6f0 [] ? sock_setsockopt+0x520/0x6f0 [] dev_hard_start_xmit+0x2ef/0x650 Oops might happen because we perform parallel putting new entries in a queue (rt2x00queue_write_tx_frame()) and removing entries after finishing transmitting (rt2800usb_work_txdone()). There are cases when _txdone may process an entry that was not fully send and nullify entry->skb . To fix check in _txdone if entry has flags that indicate pending transmission and wait until flags get cleared. Reported-by: Justin Piszcz Cc: stable@kernel.org Signed-off-by: Stanislaw Gruszka Acked-by: Ivo van Doorn Signed-off-by: John W. Linville --- drivers/net/wireless/rt2x00/rt2800usb.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/drivers/net/wireless/rt2x00/rt2800usb.c b/drivers/net/wireless/rt2x00/rt2800usb.c index 939563162fb3..2cb25ea13c52 100644 --- a/drivers/net/wireless/rt2x00/rt2800usb.c +++ b/drivers/net/wireless/rt2x00/rt2800usb.c @@ -464,6 +464,15 @@ static bool rt2800usb_txdone_entry_check(struct queue_entry *entry, u32 reg) int wcid, ack, pid; int tx_wcid, tx_ack, tx_pid; + if (test_bit(ENTRY_OWNER_DEVICE_DATA, &entry->flags) || + !test_bit(ENTRY_DATA_STATUS_PENDING, &entry->flags)) { + WARNING(entry->queue->rt2x00dev, + "Data pending for entry %u in queue %u\n", + entry->entry_idx, entry->queue->qid); + cond_resched(); + return false; + } + wcid = rt2x00_get_field32(reg, TX_STA_FIFO_WCID); ack = rt2x00_get_field32(reg, TX_STA_FIFO_TX_ACK_REQUIRED); pid = rt2x00_get_field32(reg, TX_STA_FIFO_PID_TYPE); @@ -558,8 +567,10 @@ static void rt2800usb_work_txdone(struct work_struct *work) while (!rt2x00queue_empty(queue)) { entry = rt2x00queue_get_entry(queue, Q_INDEX_DONE); - if (test_bit(ENTRY_OWNER_DEVICE_DATA, &entry->flags)) + if (test_bit(ENTRY_OWNER_DEVICE_DATA, &entry->flags) || + !test_bit(ENTRY_DATA_STATUS_PENDING, &entry->flags)) break; + if (test_bit(ENTRY_DATA_IO_FAILED, &entry->flags)) rt2x00lib_txdone_noinfo(entry, TXDONE_FAILURE); else if (rt2x00queue_status_timeout(entry)) -- 2.30.2