Hi all,

I found one bug for enabling Hikey's usb gadget driver; this bug only happen when I use linux-linaro-lsk-v4.1-android but linux-linaro-lsk-v4.1 has no such issue.

The detailed info for this bug is: When system bootup, I use configfs to enable ethernet on USB, kernel dumps below backtrace. After narrow down this issue, found below patch introduce this issue:

commit 3fdf0dcfea876a0d730da5544f947b0a19c37fdc Author: Badhri Jagan Sridharan Badhri@google.com Date: Wed Sep 24 18:58:23 2014 -0700

usb: u_ether: Add workqueue as bottom half handler for rx data path

u_ether driver passes rx data to network layer and resubmits the request back to usb hardware in interrupt context. Network layer processes rx data by scheduling tasklet. For high throughput scenarios on rx data path driver is spending lot of time in interrupt context due to rx data processing by tasklet and continuous completion and re-submission of the usb requests which results in watchdog bark. Hence move the rx data processing and usb request submission to a workqueue bottom half handler.

Change-Id: I316de8e267997137ac189a8b7b2846fa325f4a5a Signed-off-by: Badhri Jagan Sridharan Badhri@google.com

I'm not familiar with USB driver, so want to get some suggestion to fix this issue. BTW, I also searched this patch, but this patch have not been really merged into mainline kernel.

Thanks, Leo Yan

--- Kernel dump log ---

Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent permitted by applicable law. [ 11.638907] using random self ethernet address [ 11.643381] using random host ethernet address [ 11.677646] usb0: HOST MAC 0a:70:5f:8a:c1:aa [ 11.682136] usb0: MAC 1e:84:31:c3:50:0f [ 11.689207] dwc2 f72c0000.usb: bound driver configfs-gadget [ 11.701933] dwc2 f72c0000.usb: bound driver configfs-gadget SIOCSIFHWADDR: Device or resource busy - you may need to down the interface root@linaro-developer:~# [ 12.009430] dwc2 f72c0000.usb: new device is high-speed [ 12.094179] dwc2 f72c0000.usb: new device is high-speed [ 12.164194] dwc2 f72c0000.usb: new address 53 [ 12.191379] configfs-gadget gadget: high-speed config #1: c [ 12.256053] ------------[ cut here ]------------ [ 12.260753] WARNING: CPU: 0 PID: 0 at kernel/workqueue.c:1369 __queue_work+0x2dc/0x354() [ 12.268861] Modules linked in: [ 12.271932] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.1.15+ #86 [ 12.278033] Hardware name: HiKey Development Board (DT) [ 12.283265] Call trace: [ 12.285722] [<ffffffc00008a928>] dump_backtrace+0x0/0x164 [ 12.291131] [<ffffffc00008aaac>] show_stack+0x20/0x28 [ 12.296196] [<ffffffc0006f0b38>] dump_stack+0x84/0xc4 [ 12.301260] [<ffffffc0000bc960>] warn_slowpath_common+0xa8/0xdc [ 12.307192] [<ffffffc0000bcae0>] warn_slowpath_null+0x38/0x44 [ 12.312959] [<ffffffc0000d51d8>] __queue_work+0x2dc/0x354 [ 12.318377] [<ffffffc0000d52d0>] queue_work_on+0x80/0xa4 [ 12.323712] [<ffffffc00057e748>] rx_complete+0xd4/0x1ac [ 12.328958] [<ffffffc00057c110>] usb_gadget_giveback_request+0x2c/0x38 [ 12.335510] [<ffffffc0005516d4>] s3c_hsotg_complete_request+0xdc/0x1ec [ 12.342059] [<ffffffc000553e08>] s3c_hsotg_handle_outdone+0xa4/0x1d0 [ 12.348433] [<ffffffc0005541d0>] s3c_hsotg_epint+0x29c/0x6f4 [ 12.354112] [<ffffffc000554dd8>] s3c_hsotg_irq+0x408/0x734 [ 12.359621] [<ffffffc00010fca4>] handle_irq_event_percpu+0x64/0x210 [ 12.365909] [<ffffffc00010fea4>] handle_irq_event+0x54/0x80 [ 12.371501] [<ffffffc000112f6c>] handle_fasteoi_irq+0xb4/0x178 [ 12.377355] [<ffffffc00010f214>] generic_handle_irq+0x3c/0x54 [ 12.383121] [<ffffffc00010f564>] __handle_domain_irq+0x6c/0xbc [ 12.388972] [<ffffffc000082494>] gic_handle_irq+0x3c/0x88 [ 12.394388] Exception stack(0xffffffc000a83d30 to 0xffffffc000a83e50) [ 12.400850] 3d20: d91bd3d5 00000002 00b0bce0 ffffffc0 [ 12.409063] 3d40: 00a83e70 ffffffc0 005ae31c ffffffc0 00000000 00000000 005ae318 ffffffc0 [ 12.417275] 3d60: 00a80000 ffffffc0 005d8518 ffffffc0 00000020 00000000 004ea4a9 00000000 [ 12.425487] 3d80: 5fe6aba0 00023c34 00000019 00000000 b5193519 00000032 00084800 ffffffc0 [ 12.433697] 3da0: 00000000 00000000 00000000 00000000 34d5d91d 00000000 00000000 00000000 [ 12.441908] 3dc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 [ 12.450120] 3de0: 00000000 00000000 d91bd3d5 00000002 00b0bce0 ffffffc0 3a3bfe00 ffffffc0 [ 12.458332] 3e00: 00000002 00000000 00000001 00000000 00000000 00000000 d8fad491 00000002 [ 12.466544] 3e20: 00a64b50 ffffffc0 00a6a1d8 ffffffc0 007099b0 ffffffc0 00a83e70 ffffffc0 [ 12.474753] 3e40: 005ae318 ffffffc0 00a83e70 ffffffc0 [ 12.479822] [<ffffffc0000855ac>] el1_irq+0x6c/0xe0 [ 12.484634] [<ffffffc0005ae568>] cpuidle_enter+0x30/0x3c [ 12.489967] [<ffffffc0000fff98>] call_cpuidle+0x44/0x78 [ 12.495212] [<ffffffc0001001f8>] cpu_startup_entry+0x22c/0x314 [ 12.501064] [<ffffffc0006ebc44>] rest_init+0x8c/0x94 [ 12.506051] [<ffffffc0009b3980>] start_kernel+0x394/0x3a8 [ 12.511466] ---[ end trace 7240af96fd6fdc18 ]---