Date:	Tue, 11 Nov 2014 12:35:57 -0500
From:	Mathy Vanhoef <vanhoefm@...il.com>
To:	Arend van Spriel <arend@...adcom.com>, brudley@...adcom.com,
	frankyl@...adcom.com, meuleman@...adcom.com,
	linville@...driver.com, pieterpg@...adcom.com,
	linux-wireless@...r.kernel.org, brcm80211-dev-list@...adcom.com,
	netdev@...r.kernel.org, Oliver Neukum <oneukum@...e.de>
Subject: Re: [PATCH] brcmfmac: unlink URB when request timed out

Using usb_kill_urb() instead of usb_unlink_urb() seems to work without any problems.

On 11/11/2014 06:05 AM, Arend van Spriel wrote:
> On 10-11-14 17:08, Mathy Vanhoef wrote:
>> On 11/10/2014 06:18 AM, Arend van Spriel wrote:
>>> On 09-11-14 19:10, Mathy Vanhoef wrote:
>>>> From: Mathy Vanhoef <vanhoefm@...il.com>
>>>>
>>>> Unlink the submitted URB in brcmf_usb_dl_cmd if the request timed out. This
>>>> assures the URB is never submitted twice, preventing a driver crash.
>>>
>>> Hi Mathy,
>>>
>>> What driver crash are you referring to? The log only shows the WARNING
>>> ending in a USB disconnect but no actual crash. Does your patch get the
>>> driver running properly or does it only avoid the warning.
>>
>> Hi Arend,
>>
>> It shows a warning, after which the device doesn't work (but the computer is
>> still usable). But I've noticed that when *unplugging* the USB cable the OS may
>> freeze. This doesn't always happen though, sometimes unplugging works OK. The
>> patch both avoids the warning, and gets the device/driver running properly
>> (unplugging also works OK).
>>
>>>
>>> With that said, it seems there is some need for improvement, but I also
>>> notice you are running this on a virtual machine so could that affect
>>> the timeout to kick in before completion. Could you try to increase the
>>> timeout. Still when a timeout occurs this needs to be handled properly.
>>> Could you also try the following patch?
>>
>> I did a few additional tests:
>>
>> 1. When increasing IOCTL_RESP_TIMEOUT to 20000 (ten times the normal value) the
>>    timeout and warning still occur. Device/driver doesn't work.
>> 2. When increasing BRCMF_USB_RESET_GETVER_SPINWAIT to 1000 (ten timers the
>>    normal value) everything works. Device/driver works.
> 
> This means the ctl_urb completes on your system within 3sec, but not
> within 2.1sec. After discussing this with my colleague, we think you
> should use usb_kill_urb() instead of usb_unlink_urb() as it assures the
> completion handler is called. Could you retest that and let us know.
> 
> Regards,
> Arend
> 
>> 3. Quick test using backports-3.18-rc1-1 (aka unpatched driver) on a non-
>>    virtualized Linux install: In that case everything worked fine. So the bug
>>    may only be triggered in a virtualized environment / VMWare.
>> 4. When applying your patch, the driver stops early during initialization of
>>    the device. I included a WARN_ONCE before returning EINVAL and got the
>>    output below.
>>
>> Kind regards,
>> Mathy
>> ---
>> [  220.955647] usb 1-1: new high-speed USB device number 3 using ehci-pci
>> [  221.487797] usb 1-1: New USB device found, idVendor=043e, idProduct=3004
>> [  221.487802] usb 1-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
>> [  221.487804] usb 1-1: Product: Remote Download Wireless Adapter
>> [  221.487806] usb 1-1: Manufacturer: Broadcom
>> [  221.487808] usb 1-1: SerialNumber: 000000000001
>> [  221.490472] brcmfmac: brcmf_usb_probe Enter 0x043e:0x3004
>> [  221.490476] brcmfmac: brcmf_usb_probe Broadcom high speed USB WLAN interface detected
>> [  221.490477] brcmfmac: brcmf_usb_probe_cb Enter
>> [  221.490480] brcmfmac: brcmf_usb_attach Enter
>> [  221.490494] brcmfmac: brcmf_usb_dlneeded Enter
>> [  221.490495] ------------[ cut here ]------------
>> [  221.490503] WARNING: CPU: 0 PID: 100 at drivers/net/wireless/brcm80211/brcmfmac/usb.c:716 brcmf_usb_dl_cmd+0x75/0x1a0 [brcmfmac]()
>> [  221.490505] EINVAL devinfo=c0044000 ctl_rub=ef898380 completed=0
>> [  221.490506] Modules linked in: brcmfmac brcmutil vmw_pvscsi pcnet32 mptspi mptscsih mptbase
>> [  221.490514] CPU: 0 PID: 100 Comm: kworker/0:1 Not tainted 3.18.0-rc3-wl+ #2
>> [  221.490515] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 07/31/2013
>> [  221.490528] Workqueue: usb_hub_wq hub_event
>> [  221.490530]  00000000 00000000 eecffb58 c1711f4a eecffb98 eecffb88 c103edaf f11cbc58
>> [  221.490534]  eecffbb4 00000064 f11cbc84 000002cc f11c1595 f11c1595 c0044000 ffffffea
>> [  221.490537]  ef726000 eecffba0 c103ee4e 00000009 eecffb98 f11cbc58 eecffbb4 eecffbd0
>> [  221.490541] Call Trace:
>> [  221.490550]  [<c1711f4a>] dump_stack+0x41/0x52
>> [  221.490558]  [<c103edaf>] warn_slowpath_common+0x7f/0xa0
>> [  221.490563]  [<f11c1595>] ? brcmf_usb_dl_cmd+0x75/0x1a0 [brcmfmac]
>> [  221.490567]  [<f11c1595>] ? brcmf_usb_dl_cmd+0x75/0x1a0 [brcmfmac]
>> [  221.490570]  [<c103ee4e>] warn_slowpath_fmt+0x2e/0x30
>> [  221.490575]  [<f11c1595>] brcmf_usb_dl_cmd+0x75/0x1a0 [brcmfmac]
>> [  221.490580]  [<f11c2cd8>] brcmf_usb_probe+0x3c8/0x640 [brcmfmac]
>> [  221.490583]  [<c1717d53>] ? mutex_lock+0x13/0x32
>> [  221.490586]  [<c1493ae3>] usb_probe_interface+0xa3/0x180
>> [  221.490590]  [<c13f5690>] ? __driver_attach+0x90/0x90
>> [  221.490592]  [<c13f546e>] driver_probe_device+0x5e/0x1f0
>> [  221.490595]  [<c13f5690>] ? __driver_attach+0x90/0x90
>> [  221.490597]  [<c13f56c9>] __device_attach+0x39/0x50
>> [  221.490600]  [<c13f3d84>] bus_for_each_drv+0x34/0x70
>> [  221.490602]  [<c13f53db>] device_attach+0x7b/0x90
>> [  221.490604]  [<c13f5690>] ? __driver_attach+0x90/0x90
>> [  221.490607]  [<c13f4b8f>] bus_probe_device+0x6f/0x90
>> [  221.490609]  [<c13f3256>] device_add+0x426/0x520
>> [  221.490611]  [<c1491503>] ? usb_control_msg+0xb3/0xd0
>> [  221.490614]  [<c1717d53>] ? mutex_lock+0x13/0x32
>> [  221.490627]  [<c14922f8>] usb_set_configuration+0x3f8/0x700
>> [  221.490630]  [<c13f5690>] ? __driver_attach+0x90/0x90
>> [  221.490633]  [<c149ac7b>] generic_probe+0x2b/0x90
>> [  221.490637]  [<c1188bc0>] ? sysfs_create_link+0x20/0x40
>> [  221.490639]  [<c1492bec>] usb_probe_device+0xc/0x10
>> [  221.490641]  [<c13f546e>] driver_probe_device+0x5e/0x1f0
>> [  221.490644]  [<c13f5690>] ? __driver_attach+0x90/0x90
>> [  221.490646]  [<c13f56c9>] __device_attach+0x39/0x50
>> [  221.490649]  [<c13f3d84>] bus_for_each_drv+0x34/0x70
>> [  221.490651]  [<c13f53db>] device_attach+0x7b/0x90
>> [  221.490653]  [<c13f5690>] ? __driver_attach+0x90/0x90
>> [  221.490656]  [<c13f4b8f>] bus_probe_device+0x6f/0x90
>> [  221.490658]  [<c13f3256>] device_add+0x426/0x520
>> [  221.490661]  [<c148aa2e>] ? usb_new_device+0x16e/0x3a0
>> [  221.490663]  [<c148aad7>] usb_new_device+0x217/0x3a0
>> [  221.490666]  [<c148bff7>] hub_event+0xa17/0xda0
>> [  221.490668]  [<c1716918>] ? __schedule+0x2f8/0x710
>> [  221.490672]  [<c105127c>] ? pwq_dec_nr_in_flight+0x3c/0x90
>> [  221.490674]  [<c10513ee>] process_one_work+0x11e/0x360
>> [  221.490677]  [<c1051750>] worker_thread+0xf0/0x3c0
>> [  221.490680]  [<c106e14a>] ? __wake_up_locked+0x1a/0x20
>> [  221.490682]  [<c1051660>] ? process_scheduled_works+0x30/0x30
>> [  221.490685]  [<c1055b56>] kthread+0x96/0xb0
>> [  221.490687]  [<c1050000>] ? put_unbound_pool+0x110/0x170
>> [  221.490691]  [<c1719c81>] ret_from_kernel_thread+0x21/0x30
>> [  221.490693]  [<c1055ac0>] ? kthread_worker_fn+0x110/0x110
>> [  221.490695] ---[ end trace 9befd914693f3083 ]---
>> [  221.490697] brcmfmac: brcmf_usb_dlneeded chip 57005 rev 0xf11cfcec
>> [  221.490699] brcmfmac: brcmf_fw_get_firmwares enter: dev=1-1
>>
>> diff --git a/drivers/net/wireless/brcm80211/brcmfmac/usb.c b/drivers/net/wireless/brcm80211/brcmfmac/usb.c
>> index 5265aa7..15b1aa7 100644
>> --- a/drivers/net/wireless/brcm80211/brcmfmac/usb.c
>> +++ b/drivers/net/wireless/brcm80211/brcmfmac/usb.c
>> @@ -709,8 +709,13 @@ static int brcmf_usb_dl_cmd(struct brcmf_usbdev_info *devinfo, u8 cmd,
>>  	char *tmpbuf;
>>  	u16 size;
>>  
>> -	if ((!devinfo) || (devinfo->ctl_urb == NULL))
>> +	if (!devinfo || !devinfo->ctl_urb || !devinfo->ctl_completed) {
>> +		WARN_ONCE(1, "EINVAL devinfo=%p ctl_rub=%p completed=%d\n",
>> +			devinfo,
>> +			devinfo ? devinfo->ctl_urb : NULL,
>> +			devinfo ? devinfo->ctl_completed : -1);
>>  		return -EINVAL;
>> +	}
>>  
>>  	tmpbuf = kmalloc(buflen, GFP_ATOMIC);
>>  	if (!tmpbuf)
>>
>>
>>>
>>> Regards,
>>> Arend
>>> ---
>>>  drivers/net/wireless/brcm80211/brcmfmac/usb.c | 2 +-
>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/net/wireless/brcm80211/brcmfmac/usb.c
>>> b/drivers/net/wireles
>>> index dc13591..786c40b 100644
>>> --- a/drivers/net/wireless/brcm80211/brcmfmac/usb.c
>>> +++ b/drivers/net/wireless/brcm80211/brcmfmac/usb.c
>>> @@ -640,7 +640,7 @@ static int brcmf_usb_dl_cmd(struct brcmf_usbdev_info
>>> *devinf
>>>         char *tmpbuf;
>>>         u16 size;
>>>
>>> -       if ((!devinfo) || (devinfo->ctl_urb == NULL))
>>> +       if (!devinfo || !devinfo->ctl_urb || !devinfo->ctl_completed)
>>>                 return -EINVAL;
>>>
>>>         tmpbuf = kmalloc(buflen, GFP_ATOMIC);
>>>
>>>> Signed-off-by: Mathy Vanhoef <vanhoefm@...il.com>
>>>> ---
>>>> Currently brcmfmac may crash when a USB device is attached (tested with a LG
>>>> TWFM-B003D). In particular it fails on the second call to brcmf_usb_dl_cmd in
>>>> the while loop of brcmf_usb_resetcfg. The problem is that an URB is being
>>>> submitted twice:
>>>>
>>>> [  169.861800] brcmfmac: brcmf_usb_dl_writeimage Enter, fw f14db000, len 348160
>>>> [  171.787791] brcmfmac: brcmf_usb_dl_writeimage Exit, err=0
>>>> [  171.787797] brcmfmac: brcmf_usb_dlstart Exit, err=0
>>>> [  171.787799] brcmfmac: brcmf_usb_dlrun Enter
>>>> [  171.791794] brcmfmac: brcmf_usb_resetcfg Enter
>>>> [  173.988072] ------------[ cut here ]------------
>>>> [  173.988083] WARNING: CPU: 0 PID: 369 at drivers/usb/core/urb.c:339 usb_submit_urb+0x4e6/0x500()
>>>> [  173.988085] URB eaf45f00 submitted while active
>>>> [  173.988086] Modules linked in: brcmfmac brcmutil vmw_pvscsi pcnet32 mptspi mptscsih mptbase
>>>> [  173.988100] CPU: 0 PID: 369 Comm: kworker/0:2 Not tainted 3.18.0-rc3-wl #1
>>>> [  173.988102] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 07/31/2013
>>>> [  173.988106] Workqueue: events request_firmware_work_func
>>>> [  173.988108]  00000000 00000000 ee747db8 c1711f4a ee747df8 ee747de8 c103edaf c18d1e10
>>>> [  173.988112]  ee747e14 00000171 c18a8b29 00000153 c1490556 c1490556 eaf45f00 eafdc660
>>>> [  173.988115]  f14b8fa0 ee747e00 c103ee4e 00000009 ee747df8 c18d1e10 ee747e14 ee747e50
>>>> [  173.988119] Call Trace:
>>>> [  173.988129]  [<c1711f4a>] dump_stack+0x41/0x52
>>>> [  173.988136]  [<c103edaf>] warn_slowpath_common+0x7f/0xa0
>>>> [  173.988139]  [<c1490556>] ? usb_submit_urb+0x4e6/0x500
>>>> [  173.988141]  [<c1490556>] ? usb_submit_urb+0x4e6/0x500
>>>> [  173.988147]  [<f14b8fa0>] ? brcmf_usb_ioctl_resp_wake+0x40/0x40 [brcmfmac]
>>>> [  173.988150]  [<c103ee4e>] warn_slowpath_fmt+0x2e/0x30
>>>> [  173.988152]  [<c1490556>] usb_submit_urb+0x4e6/0x500
>>>> [  173.988156]  [<c1123de1>] ? __kmalloc+0x21/0x140
>>>> [  173.988161]  [<f14b91c3>] ? brcmf_usb_dl_cmd+0x33/0x120 [brcmfmac]
>>>> [  173.988166]  [<f14b9243>] brcmf_usb_dl_cmd+0xb3/0x120 [brcmfmac]
>>>> [  173.988170]  [<f14ba6c4>] brcmf_usb_probe_phase2+0x4e4/0x640 [brcmfmac]
>>>> [  173.988176]  [<f14b4900>] brcmf_fw_request_code_done+0xd0/0xf0 [brcmfmac]
>>>> [  173.988178]  [<c1400876>] request_firmware_work_func+0x26/0x50
>>>> [  173.988182]  [<c10513ee>] process_one_work+0x11e/0x360
>>>> [  173.988184]  [<c1051750>] worker_thread+0xf0/0x3c0
>>>> [  173.988205]  [<c106e14a>] ? __wake_up_locked+0x1a/0x20
>>>> [  173.988208]  [<c1051660>] ? process_scheduled_works+0x30/0x30
>>>> [  173.988211]  [<c1055b56>] kthread+0x96/0xb0
>>>> [  173.988214]  [<c1719c81>] ret_from_kernel_thread+0x21/0x30
>>>> [  173.988217]  [<c1055ac0>] ? kthread_worker_fn+0x110/0x110
>>>> [  173.988219] ---[ end trace 0c88bf46801de083 ]---
>>>> [  173.988221] brcmf_usb_dl_cmd: usb_submit_urb failed -16
>>>> [  173.988396] brcmfmac: brcmf_usb_probe_phase2 failed: dev=1-1, err=-19
>>>> [  173.989503] brcmfmac: brcmf_usb_disconnect Enter
>>>>
>>>> This patch fixes the brcmf_usb_dl_cmd function to prevent an URB from being
>>>> submitted twice. Tested using a LG TWFM-B003D, which now works properly.
>>>>
>>>>
>>>>  drivers/net/wireless/brcm80211/brcmfmac/usb.c |    6 ++++--
>>>>  1 file changed, 4 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/drivers/net/wireless/brcm80211/brcmfmac/usb.c b/drivers/net/wireless/brcm80211/brcmfmac/usb.c
>>>> index 5265aa7..1bc7858 100644
>>>> --- a/drivers/net/wireless/brcm80211/brcmfmac/usb.c
>>>> +++ b/drivers/net/wireless/brcm80211/brcmfmac/usb.c
>>>> @@ -738,10 +738,12 @@ static int brcmf_usb_dl_cmd(struct brcmf_usbdev_info *devinfo, u8 cmd,
>>>>  		goto finalize;
>>>>  	}
>>>>  
>>>> -	if (!brcmf_usb_ioctl_resp_wait(devinfo))
>>>> +	if (!brcmf_usb_ioctl_resp_wait(devinfo)) {
>>>> +		usb_unlink_urb(devinfo->ctl_urb);
>>>>  		ret = -ETIMEDOUT;
>>>> -	else
>>>> +	} else {
>>>>  		memcpy(buffer, tmpbuf, buflen);
>>>> +	}
>>>>  
>>>>  finalize:
>>>>  	kfree(tmpbuf);
>>>>
>>>
> 
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