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Date: Wed, 7 Jan 2009 18:37:58 -0800
From: "Andrey Yurovsky" <andrey@cozybit.com>
To: libertas-dev@lists.infradead.org,
	linux-wireless <linux-wireless@vger.kernel.org>
Subject: Re: libertas: BUG: unable to handle paging request
Cc: wangchen@cn.fujitsu.com
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The commit that caused this regression is
29726d85d7b98558a8bc8e69b859bf12e1347f9f "netdevice libertas: Fix
directly reference of netdev->priv" by Wang Chen.  It probably causes
a problem with netdev->priv's offset and then we get a pointer
dereference problem when lbs_get_freq() tries to use its priv data.

  -Andrey

On Wed, Jan 7, 2009 at 4:58 PM, Andrey Yurovsky <andrey@cozybit.com> wrote:
> Hello.  I noticed that the libertas driver causes a kernel oops in
> more recent wireless-testing kernels (I am bisecting right now to
> narrow this down).  To reproduce, load the driver and run iwconfig,
> causing lbs_get_freq() to be called.
>
> So far I know that this problem doesn't exist at the 2.6.28-rc2 tag
> (commit 0173a3265b228da319ceb9c1ec6a5682fd1b2d92)  but I have seen it
> in -rc7 and up through today's wireless-testing.  It seems that
> there's a regression somewhere after -rc2.  I've reproduced this with
> the USB hardware as well as an SDIO board.
>
> [  118.571205] BUG: unable to handle kernel paging request at 00001e01
> [  118.578500] IP: [<c81fddda>] lbs_get_freq+0x1a/0x160 [libertas]
> [  118.585417] *pde = 00000000
> [  118.588877] Oops: 0000 [#1]
> [  118.592092] last sysfs file: /sys/block/ram9/range
> [  118.592385] Modules linked in: usb8xxx libertas lib80211
> [  118.592385]
> [  118.592385] Pid: 2317, comm: iwconfig Not tainted (2.6.28-wl #65) Uknown
> [  118.592385] EIP: 0060:[<c81fddda>] EFLAGS: 00010293 CPU: 0
> [  118.592385] EIP is at lbs_get_freq+0x1a/0x160 [libertas]
> [  118.592385] EAX: 00000000 EBX: 00000000 ECX: c6891ef8 EDX: c6891e98
> [  118.592385] ESI: c6891ef8 EDI: c6891ef8 EBP: c7295000 ESP: c6891e10
> [  118.592385]  DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 0068
> [  118.592385] Process iwconfig (pid: 2317, ti=c6890000 task=c7349880
> task.ti=c6890000)
> [  118.592385] Stack:
> [  118.592385]  c8201b4b c6891ef8 00000010 ffffffa1 00008b05 c038aa20
> 00000000 c03c691c
> [  118.592385]  00000000 c04bc7e0 c0301287 b7f01d70 c68ce000 c6895000
> c04c8260 00000c04
> [  118.592385]  c68c7b7c 00000000 c7295000 c6891ee8 c0300325 c6891ee8
> c7295000 c6891ee8
> [  118.592385] Call Trace:
> [  118.592385]  [<c8201b4b>] lbs_get_name+0x2b/0xb0 [libertas]
> [  118.592385]  [<c038aa20>] ioctl_standard_call+0x60/0x3a0
> [  118.592385]  [<c0301287>] netif_receive_skb+0x1d7/0x3e0
> [  118.592385]  [<c0300325>] __dev_get_by_name+0x75/0x90
> [  118.592385]  [<c0300325>] __dev_get_by_name+0x75/0x90
> [  118.592385]  [<c038a687>] wext_handle_ioctl+0x157/0x230
> [  118.592385]  [<c81fddc0>] lbs_get_freq+0x0/0x160 [libertas]
> [  118.592385]  [<c03034c4>] dev_ioctl+0x304/0x4f0
> [  118.592385]  [<c02ffdd2>] net_rx_action+0x92/0x140
> [  118.592385]  [<c027ca89>] pty_write+0x39/0x60
> [  118.592385]  [<c02f4280>] sock_ioctl+0x0/0x260
> [  118.592385]  [<c017e27f>] vfs_ioctl+0x1f/0x70
> [  118.592385]  [<c017e65b>] do_vfs_ioctl+0x24b/0x490
> [  118.592385]  [<c011654e>] update_curr+0x13e/0x190
> [  118.592385]  [<c0117fab>] set_next_entity+0x2b/0x70
> [  118.592385]  [<c0397c64>] schedule+0x1b4/0x350
> [  118.592385]  [<c017e906>] sys_ioctl+0x66/0x70
> [  118.592385]  [<c0103cd2>] syscall_call+0x7/0xb
> [  118.592385] Code: e9 38 ff ff ff 8d b6 00 00 00 00 8d bf 00 00 00
> 00 56 89 ce 53 83 ec 0c 8b 98 a4 01 00 00 a1 80 19 22 c8 83 e0 21 83
> f8 21 74 42 <0f> b6 8b 01 1e 00 00 31 d2 89 d8 e8 a6 fe ff ff 85 c0 0f
> 84 cd
> [  118.592385] EIP: [<c81fddda>] lbs_get_freq+0x1a/0x160 [libertas]
> SS:ESP 0068:c6891e10
> [  118.594153] ---[ end trace f426cd49b2b378f4 ]---
>