This is a note to let you know that I've just added the patch titled

    rt2x00: fix crash in rt2800usb_write_tx_desc

to the 3.0-stable tree which can be found at:
    
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     rt2x00-fix-crash-in-rt2800usb_write_tx_desc.patch
and it can be found in the queue-3.0 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <sta...@kernel.org> know about it.


>From sgrus...@redhat.com  Mon Aug 29 15:23:55 2011
From: Stanislaw Gruszka <sgrus...@redhat.com>
Date: Thu, 25 Aug 2011 17:14:24 +0200
Subject: rt2x00: fix crash in rt2800usb_write_tx_desc
To: sta...@kernel.org
Cc: ivdo...@gmail.com, Stanislaw Gruszka <sgrus...@redhat.com>, 
jpis...@lucidpixels.com, "John W. Linville" <linvi...@tuxdriver.com>
Message-ID: <1314285266-5098-1-git-send-email-sgrus...@redhat.com>

From: Stanislaw Gruszka <sgrus...@redhat.com>

commit 4b1bfb7d2d125af6653d6c2305356b2677f79dc6 upstream.

Patch should fix this oops:

BUG: unable to handle kernel NULL pointer dereference at 000000a0
IP: [<f8e06078>] rt2800usb_write_tx_desc+0x18/0xc0 [rt2800usb]
*pdpt = 000000002408c001 *pde = 0000000024079067 *pte = 0000000000000000
Oops: 0000 [#1] SMP
EIP: 0060:[<f8e06078>] 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:
 [<f8da5e85>] rt2x00queue_write_tx_frame+0x155/0x300 [rt2x00lib]
 [<f8da424c>] rt2x00mac_tx+0x7c/0x370 [rt2x00lib]
 [<c04882b2>] ? mark_held_locks+0x62/0x90
 [<c081f645>] ? _raw_spin_unlock_irqrestore+0x35/0x60
 [<c04884ba>] ? trace_hardirqs_on_caller+0x5a/0x170
 [<c04885db>] ? trace_hardirqs_on+0xb/0x10
 [<f8d618ac>] __ieee80211_tx+0x5c/0x1e0 [mac80211]
 [<f8d631fc>] ieee80211_tx+0xbc/0xe0 [mac80211]
 [<f8d63163>] ? ieee80211_tx+0x23/0xe0 [mac80211]
 [<f8d632e1>] ieee80211_xmit+0xc1/0x200 [mac80211]
 [<f8d63220>] ? ieee80211_tx+0xe0/0xe0 [mac80211]
 [<c0487d45>] ? lock_release_holdtime+0x35/0x1b0
 [<f8d63986>] ? ieee80211_subif_start_xmit+0x446/0x5f0 [mac80211]
 [<f8d637dd>] ieee80211_subif_start_xmit+0x29d/0x5f0 [mac80211]
 [<f8d63924>] ? ieee80211_subif_start_xmit+0x3e4/0x5f0 [mac80211]
 [<c0760188>] ? sock_setsockopt+0x6a8/0x6f0
 [<c0760000>] ? sock_setsockopt+0x520/0x6f0
 [<c076daef>] 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 <jpis...@lucidpixels.com>
Signed-off-by: Stanislaw Gruszka <sgrus...@redhat.com>
Acked-by: Ivo van Doorn <ivdo...@gmail.com>
Signed-off-by: John W. Linville <linvi...@tuxdriver.com>
Signed-off-by: Greg Kroah-Hartman <gre...@suse.de>
---
 drivers/net/wireless/rt2x00/rt2800lib.c |   10 ++++++++++
 drivers/net/wireless/rt2x00/rt2800usb.c |    4 +++-
 2 files changed, 13 insertions(+), 1 deletion(-)

--- a/drivers/net/wireless/rt2x00/rt2800lib.c
+++ b/drivers/net/wireless/rt2x00/rt2800lib.c
@@ -38,6 +38,7 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/slab.h>
+#include <linux/sched.h>
 
 #include "rt2x00.h"
 #include "rt2800lib.h"
@@ -607,6 +608,15 @@ static bool rt2800_txdone_entry_check(st
        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);
--- a/drivers/net/wireless/rt2x00/rt2800usb.c
+++ b/drivers/net/wireless/rt2x00/rt2800usb.c
@@ -477,8 +477,10 @@ static void rt2800usb_work_txdone(struct
                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))


Patches currently in stable-queue which might be from sgrus...@redhat.com are

queue-3.0/rt2x00-do-not-drop-usb-dev-reference-counter-on-suspend.patch
queue-3.0/mac80211-fix-suspend-resume-races-with-unregister-hw.patch
queue-3.0/rt2x00-fix-crash-in-rt2800usb_write_tx_desc.patch
queue-3.0/rt2x00-fix-crash-in-rt2800usb_get_txwi.patch

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