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

    Bluetooth: hci_core: fix NULL-pointer dereference at

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:
     bluetooth-hci_core-fix-null-pointer-dereference-at.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 <[email protected]> know about it.


>From 94324962066231a938564bebad0f941cd2d06bb2 Mon Sep 17 00:00:00 2001
From: Johan Hovold <[email protected]>
Date: Thu, 15 Mar 2012 14:48:41 +0100
Subject: Bluetooth: hci_core: fix NULL-pointer dereference at
 unregister

From: Johan Hovold <[email protected]>

commit 94324962066231a938564bebad0f941cd2d06bb2 upstream.

Make sure hci_dev_open returns immediately if hci_dev_unregister has
been called.

This fixes a race between hci_dev_open and hci_dev_unregister which can
lead to a NULL-pointer dereference.

Bug is 100% reproducible using hciattach and a disconnected serial port:

0. # hciattach -n /dev/ttyO1 any noflow

1. hci_dev_open called from hci_power_on grabs req lock
2. hci_init_req executes but device fails to initialise (times out
   eventually)
3. hci_dev_open is called from hci_sock_ioctl and sleeps on req lock
4. hci_uart_tty_close calls hci_dev_unregister and sleeps on req lock in
   hci_dev_do_close
5. hci_dev_open (1) releases req lock
6. hci_dev_do_close grabs req lock and returns as device is not up
7. hci_dev_unregister sleeps in destroy_workqueue
8. hci_dev_open (3) grabs req lock, calls hci_init_req and eventually sleeps
9. hci_dev_unregister finishes, while hci_dev_open is still running...

[   79.627136] INFO: trying to register non-static key.
[   79.632354] the code is fine but needs lockdep annotation.
[   79.638122] turning off the locking correctness validator.
[   79.643920] [<c00188bc>] (unwind_backtrace+0x0/0xf8) from [<c00729c4>] 
(__lock_acquire+0x1590/0x1ab0)
[   79.653594] [<c00729c4>] (__lock_acquire+0x1590/0x1ab0) from [<c00733f8>] 
(lock_acquire+0x9c/0x128)
[   79.663085] [<c00733f8>] (lock_acquire+0x9c/0x128) from [<c0040a88>] 
(run_timer_softirq+0x150/0x3ac)
[   79.672668] [<c0040a88>] (run_timer_softirq+0x150/0x3ac) from [<c003a3b8>] 
(__do_softirq+0xd4/0x22c)
[   79.682281] [<c003a3b8>] (__do_softirq+0xd4/0x22c) from [<c003a924>] 
(irq_exit+0x8c/0x94)
[   79.690856] [<c003a924>] (irq_exit+0x8c/0x94) from [<c0013a50>] 
(handle_IRQ+0x34/0x84)
[   79.699157] [<c0013a50>] (handle_IRQ+0x34/0x84) from [<c0008530>] 
(omap3_intc_handle_irq+0x48/0x4c)
[   79.708648] [<c0008530>] (omap3_intc_handle_irq+0x48/0x4c) from [<c037499c>] 
(__irq_usr+0x3c/0x60)
[   79.718048] Exception stack(0xcf281fb0 to 0xcf281ff8)
[   79.723358] 1fa0:                                     0001e6a0 be8dab00 
0001e698 00036698
[   79.731933] 1fc0: 0002df98 0002df38 0000001f 00000000 b6f234d0 00000000 
00000004 00000000
[   79.740509] 1fe0: 0001e6f8 be8d6aa0 be8dac50 0000aab8 80000010 ffffffff
[   79.747497] Unable to handle kernel NULL pointer dereference at virtual 
address 00000000
[   79.756011] pgd = cf3b4000
[   79.758850] [00000000] *pgd=8f0c7831, *pte=00000000, *ppte=00000000
[   79.765502] Internal error: Oops: 80000007 [#1]
[   79.770294] Modules linked in:
[   79.773529] CPU: 0    Tainted: G        W     (3.3.0-rc6-00002-gb5d5c87 #421)
[   79.781066] PC is at 0x0
[   79.783721] LR is at run_timer_softirq+0x16c/0x3ac
[   79.788787] pc : [<00000000>]    lr : [<c0040aa4>]    psr: 60000113
[   79.788787] sp : cf281ee0  ip : 00000000  fp : cf280000
[   79.800903] r10: 00000004  r9 : 00000100  r8 : b6f234d0
[   79.806427] r7 : c0519c28  r6 : cf093488  r5 : c0561a00  r4 : 00000000
[   79.813323] r3 : 00000000  r2 : c054eee0  r1 : 00000001  r0 : 00000000
[   79.820190] Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment user
[   79.827728] Control: 10c5387d  Table: 8f3b4019  DAC: 00000015
[   79.833801] Process gpsd (pid: 1265, stack limit = 0xcf2802e8)
[   79.839965] Stack: (0xcf281ee0 to 0xcf282000)
[   79.844573] 1ee0: 00000002 00000000 c0040a24 00000000 00000002 cf281f08 
00200200 00000000
[   79.853210] 1f00: 00000000 cf281f18 cf281f08 00000000 00000000 00000000 
cf281f18 cf281f18
[   79.861816] 1f20: 00000000 00000001 c056184c 00000000 00000001 b6f234d0 
c0561848 00000004
[   79.870452] 1f40: cf280000 c003a3b8 c051e79c 00000001 00000000 00000100 
3fa9e7b8 0000000a
[   79.879089] 1f60: 00000025 cf280000 00000025 00000000 00000000 b6f234d0 
00000000 00000004
[   79.887756] 1f80: 00000000 c003a924 c053ad38 c0013a50 fa200000 cf281fb0 
ffffffff c0008530
[   79.896362] 1fa0: 0001e6a0 0000aab8 80000010 c037499c 0001e6a0 be8dab00 
0001e698 00036698
[   79.904998] 1fc0: 0002df98 0002df38 0000001f 00000000 b6f234d0 00000000 
00000004 00000000
[   79.913665] 1fe0: 0001e6f8 be8d6aa0 be8dac50 0000aab8 80000010 ffffffff 
00fbf700 04ffff00
[   79.922302] [<c0040aa4>] (run_timer_softirq+0x16c/0x3ac) from [<c003a3b8>] 
(__do_softirq+0xd4/0x22c)
[   79.931945] [<c003a3b8>] (__do_softirq+0xd4/0x22c) from [<c003a924>] 
(irq_exit+0x8c/0x94)
[   79.940582] [<c003a924>] (irq_exit+0x8c/0x94) from [<c0013a50>] 
(handle_IRQ+0x34/0x84)
[   79.948913] [<c0013a50>] (handle_IRQ+0x34/0x84) from [<c0008530>] 
(omap3_intc_handle_irq+0x48/0x4c)
[   79.958404] [<c0008530>] (omap3_intc_handle_irq+0x48/0x4c) from [<c037499c>] 
(__irq_usr+0x3c/0x60)
[   79.967773] Exception stack(0xcf281fb0 to 0xcf281ff8)
[   79.973083] 1fa0:                                     0001e6a0 be8dab00 
0001e698 00036698
[   79.981658] 1fc0: 0002df98 0002df38 0000001f 00000000 b6f234d0 00000000 
00000004 00000000
[   79.990234] 1fe0: 0001e6f8 be8d6aa0 be8dac50 0000aab8 80000010 ffffffff
[   79.997161] Code: bad PC value
[   80.000396] ---[ end trace 6f6739840475f9ee ]---
[   80.005279] Kernel panic - not syncing: Fatal exception in interrupt

Signed-off-by: Johan Hovold <[email protected]>
Acked-by: Marcel Holtmann <[email protected]>
Signed-off-by: Johan Hedberg <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

---
 include/net/bluetooth/hci.h |    1 +
 net/bluetooth/hci_core.c    |    7 +++++++
 2 files changed, 8 insertions(+)

--- a/include/net/bluetooth/hci.h
+++ b/include/net/bluetooth/hci.h
@@ -84,6 +84,7 @@ enum {
        HCI_SERVICE_CACHE,
        HCI_LINK_KEYS,
        HCI_DEBUG_KEYS,
+       HCI_UNREGISTER,
 
        HCI_RESET,
 };
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -509,6 +509,11 @@ int hci_dev_open(__u16 dev)
 
        hci_req_lock(hdev);
 
+       if (test_bit(HCI_UNREGISTER, &hdev->flags)) {
+               ret = -ENODEV;
+               goto done;
+       }
+
        if (hdev->rfkill && rfkill_blocked(hdev->rfkill)) {
                ret = -ERFKILL;
                goto done;
@@ -1317,6 +1322,8 @@ int hci_unregister_dev(struct hci_dev *h
 
        BT_DBG("%p name %s bus %d", hdev, hdev->name, hdev->bus);
 
+       set_bit(HCI_UNREGISTER, &hdev->flags);
+
        write_lock_bh(&hci_dev_list_lock);
        list_del(&hdev->list);
        write_unlock_bh(&hci_dev_list_lock);


Patches currently in stable-queue which might be from [email protected] are

queue-3.0/bluetooth-hci_ldisc-fix-null-pointer-dereference-on-tty_close.patch
queue-3.0/usb-serial-fix-race-between-probe-and-open.patch
queue-3.0/bluetooth-hci_core-fix-null-pointer-dereference-at.patch
queue-3.0/usb-pl2303-fix-dtr-rts-being-raised-on-baud-rate-change.patch
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