From mboxrd@z Thu Jan  1 00:00:00 1970
From: abailon@baylibre.com (Alexandre Bailon)
Date: Thu, 6 Jul 2017 19:13:40 +0200
Subject: Warning dump on OMAP-L138 when g_zero module is removed
In-Reply-To: <748a9491-e834-34cb-993f-e8c7e2538961@ti.com>
References: <748a9491-e834-34cb-993f-e8c7e2538961@ti.com>
Message-ID: <260e5199-624d-b402-5481-2d818d282ce7@baylibre.com>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On 06/29/2017 03:50 PM, Sekhar Nori wrote:
> Hi Alexandre, Bin,
> 
> With latest linux-next, I see a warning dump when I remove g_zero[1] on 
> OMAP-L138 LCDK board. I am building the kernel with davinci_all_defconfig.
> 
> It is not present in latest mainline because the warnings are introduced
> with CPPI DMA getting enabled in latest -next.
> 
> Subsequent insertion of g_ether leads to a warning too[2], although the 
> gadget seems to work (ping test).
> 
> Since these are pretty annoying, it will be nice to get rid of them. I 
> have not been able to debug any further. But if you have
> ideas/experiments to try, I can do that.
I got a lot of these warnings during development but it was only for the
host mode.
If I remember correctly, the cause was a race between the teardown
function and the interrupt handler.
The teardwon descriptor was pop from the queue by the interrupt handler,
preventing cppi41_tear_down_chan() to get it, which will result after
some retries to a couple of warnings.

I will take a look to see if that is the same issue.

Thanks,
Alexandre
> 
> Thanks,
> Sekhar
> 
> [1] 
> root at omapl138-lcdk:~# modprobe g_zero
> zero gadget: Gadget Zero, version: Cinco de Mayo 2008
> zero gadget: zero ready
> musb_g_ep0_irq 712: SetupEnd came in a wrong ep0stage setup
> root at omapl138-lcdk:~# zero gadget: high-speed config #3: source/sink
> 
> root at omapl138-lcdk:~# modprobe -r g_zero                                                                                                                                                                                                      
> ------------[ cut here ]------------
> WARNING: CPU: 0 PID: 464 at drivers/dma/cppi41.c:694 cppi41_stop_chan+0x208/0x338 [cppi41]
> Modules linked in: usb_f_ss_lb g_zero(-) libcomposite configfs ofpart davinci_nand nand nand_ecc cppi41 mtd vpif_display tvp514x vpif_capture videobuf2_dma_contig videobuf2_memops videobuf2_v4l2 videobuf2_core v4l2_fwnode v4l2_common vid4
> CPU: 0 PID: 464 Comm: modprobe Tainted: G        W       4.12.0-rc7-next-20170629-10695-g3fb8ba638d53 #76
> Hardware name: Generic DA850/OMAP-L138/AM18x
> Backtrace: 
> [<c000d794>] (dump_backtrace) from [<c000da38>] (show_stack+0x18/0x1c)
>  r7:00000009 r6:00000000 r5:bf3a19f0 r4:00000000
> [<c000da20>] (show_stack) from [<c043b310>] (dump_stack+0x20/0x28)
> [<c043b2f0>] (dump_stack) from [<c001b830>] (__warn+0xdc/0x104)
> [<c001b754>] (__warn) from [<c001b910>] (warn_slowpath_null+0x28/0x30)
>  r9:000000d8 r8:bf2d9e00 r7:00000001 r6:c5b5b010 r5:c5b5b014 r4:c7b2b8a0
> [<c001b8e8>] (warn_slowpath_null) from [<bf3a075c>] (cppi41_stop_chan+0x208/0x338 [cppi41])
> [<bf3a0554>] (cppi41_stop_chan [cppi41]) from [<bf2d688c>] (cppi41_dma_channel_abort+0x118/0x290 [musb_hdrc])
>  r7:c5848010 r6:00020000 r5:00000001 r4:c7077454
> [<bf2d6774>] (cppi41_dma_channel_abort [musb_hdrc]) from [<bf2d4bcc>] (musb_gadget_disable+0xfc/0x240 [musb_hdrc])
>  r10:c7077000 r9:fee00410 r8:20000093 r7:c5848010 r6:bf2d9de4 r5:c5848010
>  r4:c5848410
> [<bf2d4ad0>] (musb_gadget_disable [musb_hdrc]) from [<bf261f8c>] (usb_ep_disable+0x30/0x3c [udc_core])
>  r10:00000000 r9:c7144000 r8:c000a604 r7:c7334ba0 r6:c584846c r5:00000000
>  r4:c5848410 r3:bf2d4ad0
> [<bf261f5c>] (usb_ep_disable [udc_core]) from [<bf3eb740>] (disable_endpoints+0x20/0x4c [usb_f_ss_lb])
>  r5:00000000 r4:00000000
> [<bf3eb720>] (disable_endpoints [usb_f_ss_lb]) from [<bf3eb7a0>] (disable_source_sink+0x34/0x3c [usb_f_ss_lb])
>  r7:c7334ba0 r6:00000000 r5:60000013 r4:c7159e40
> [<bf3eb76c>] (disable_source_sink [usb_f_ss_lb]) from [<bf3eb7b8>] (sourcesink_disable+0x10/0x14 [usb_f_ss_lb])
> [<bf3eb7a8>] (sourcesink_disable [usb_f_ss_lb]) from [<bf3d5e38>] (composite_disconnect+0x58/0xd0 [libcomposite])
> [<bf3d5de0>] (composite_disconnect [libcomposite]) from [<bf261cf8>] (usb_gadget_remove_driver+0x58/0xa8 [udc_core])
>  r7:00000081 r6:00000800 r5:c5849138 r4:c7b52600
> [<bf261ca0>] (usb_gadget_remove_driver [udc_core]) from [<bf2625b4>] (usb_gadget_unregister_driver+0x68/0xd0 [udc_core])
>  r5:bf3e591c r4:c7b52600
> [<bf26254c>] (usb_gadget_unregister_driver [udc_core]) from [<bf3d6484>] (usb_composite_unregister+0x14/0x18 [libcomposite])
>  r5:0003af5c r4:bf3e59e0
> [<bf3d6470>] (usb_composite_unregister [libcomposite]) from [<bf3e5444>] (zero_driver_exit+0x14/0x1c [g_zero])
> [<bf3e5430>] (zero_driver_exit [g_zero]) from [<c00802ec>] (SyS_delete_module+0x168/0x1e8)
> [<c0080184>] (SyS_delete_module) from [<c000a460>] (ret_fast_syscall+0x0/0x38)
>  r6:00000000 r5:0003af5c r4:0003af20
> ---[ end trace 3d9a1549a3b9c32f ]---
> ------------[ cut here ]------------
> WARNING: CPU: 0 PID: 464 at drivers/dma/cppi41.c:700 cppi41_stop_chan+0x248/0x338 [cppi41]
> Modules linked in: usb_f_ss_lb g_zero(-) libcomposite configfs ofpart davinci_nand nand nand_ecc cppi41 mtd vpif_display tvp514x vpif_capture videobuf2_dma_contig videobuf2_memops videobuf2_v4l2 videobuf2_core v4l2_fwnode v4l2_common vid4
> CPU: 0 PID: 464 Comm: modprobe Tainted: G        W       4.12.0-rc7-next-20170629-10695-g3fb8ba638d53 #76
> Hardware name: Generic DA850/OMAP-L138/AM18x
> Backtrace: 
> [<c000d794>] (dump_backtrace) from [<c000da38>] (show_stack+0x18/0x1c)
>  r7:00000009 r6:00000000 r5:bf3a19f0 r4:00000000
> [<c000da20>] (show_stack) from [<c043b310>] (dump_stack+0x20/0x28)
> [<c043b2f0>] (dump_stack) from [<c001b830>] (__warn+0xdc/0x104)
> [<c001b754>] (__warn) from [<c001b910>] (warn_slowpath_null+0x28/0x30)
>  r9:000000d8 r8:bf2d9e00 r7:00000001 r6:c5b5b010 r5:c5b5b014 r4:c7b2b8a0
> [<c001b8e8>] (warn_slowpath_null) from [<bf3a079c>] (cppi41_stop_chan+0x248/0x338 [cppi41])
> [<bf3a0554>] (cppi41_stop_chan [cppi41]) from [<bf2d688c>] (cppi41_dma_channel_abort+0x118/0x290 [musb_hdrc])
>  r7:c5848010 r6:00020000 r5:00000001 r4:c7077454
> [<bf2d6774>] (cppi41_dma_channel_abort [musb_hdrc]) from [<bf2d4bcc>] (musb_gadget_disable+0xfc/0x240 [musb_hdrc])
>  r10:c7077000 r9:fee00410 r8:20000093 r7:c5848010 r6:bf2d9de4 r5:c5848010
>  r4:c5848410
> [<bf2d4ad0>] (musb_gadget_disable [musb_hdrc]) from [<bf261f8c>] (usb_ep_disable+0x30/0x3c [udc_core])
>  r10:00000000 r9:c7144000 r8:c000a604 r7:c7334ba0 r6:c584846c r5:00000000
>  r4:c5848410 r3:bf2d4ad0
> [<bf261f5c>] (usb_ep_disable [udc_core]) from [<bf3eb740>] (disable_endpoints+0x20/0x4c [usb_f_ss_lb])
>  r5:00000000 r4:00000000
> [<bf3eb720>] (disable_endpoints [usb_f_ss_lb]) from [<bf3eb7a0>] (disable_source_sink+0x34/0x3c [usb_f_ss_lb])
>  r7:c7334ba0 r6:00000000 r5:60000013 r4:c7159e40
> [<bf3eb76c>] (disable_source_sink [usb_f_ss_lb]) from [<bf3eb7b8>] (sourcesink_disable+0x10/0x14 [usb_f_ss_lb])
> [<bf3eb7a8>] (sourcesink_disable [usb_f_ss_lb]) from [<bf3d5e38>] (composite_disconnect+0x58/0xd0 [libcomposite])
> [<bf3d5de0>] (composite_disconnect [libcomposite]) from [<bf261cf8>] (usb_gadget_remove_driver+0x58/0xa8 [udc_core])
>  r7:00000081 r6:00000800 r5:c5849138 r4:c7b52600
> [<bf261ca0>] (usb_gadget_remove_driver [udc_core]) from [<bf2625b4>] (usb_gadget_unregister_driver+0x68/0xd0 [udc_core])
>  r5:bf3e591c r4:c7b52600
> [<bf26254c>] (usb_gadget_unregister_driver [udc_core]) from [<bf3d6484>] (usb_composite_unregister+0x14/0x18 [libcomposite])
>  r5:0003af5c r4:bf3e59e0
> [<bf3d6470>] (usb_composite_unregister [libcomposite]) from [<bf3e5444>] (zero_driver_exit+0x14/0x1c [g_zero])
> [<bf3e5430>] (zero_driver_exit [g_zero]) from [<c00802ec>] (SyS_delete_module+0x168/0x1e8)
> [<c0080184>] (SyS_delete_module) from [<c000a460>] (ret_fast_syscall+0x0/0x38)
>  r6:00000000 r5:0003af5c r4:0003af20
> ---[ end trace 3d9a1549a3b9c330 ]---
> 
> [2]
> root at omapl138-lcdk:~# modprobe g_ether
> using random self ethernet address
> using random host ethernet address
> usb0: HOST MAC 66:6b:3b:7f:71:64
> usb0: MAC aa:26:23:3a:e7:b3
> using random self ethernet address
> using random host ethernet address
> g_ether gadget: Ethernet Gadget, version: Memorial Day 2008
> g_ether gadget: g_ether ready
> ------------[ cut here ]------------
> WARNING: CPU: 0 PID: 467 at drivers/dma/cppi41.c:335 cppi41_irq+0x1fc/0x230 [cppi41]
> Modules linked in: usb_f_ecm g_ether(+) usb_f_rndis u_ether usb_f_ss_lb libcomposite configfs ofpart davinci_nand nand nand_ecc cppi41 mtd vpif_display tvp514x vpif_capture videobuf2_dma_contig videobuf2_memops videobuf2_v4l2 videobuf2_c]
> CPU: 0 PID: 467 Comm: modprobe Tainted: G        W       4.12.0-rc7-next-20170629-10695-g3fb8ba638d53 #76
> Hardware name: Generic DA850/OMAP-L138/AM18x
> Backtrace: 
> [<c000d794>] (dump_backtrace) from [<c000da38>] (show_stack+0x18/0x1c)
>  r7:00000009 r6:00000000 r5:bf3a19f0 r4:00000000
> [<c000da20>] (show_stack) from [<c043b310>] (dump_stack+0x20/0x28)
> [<c043b2f0>] (dump_stack) from [<c001b830>] (__warn+0xdc/0x104)
> [<c001b754>] (__warn) from [<c001b910>] (warn_slowpath_null+0x28/0x30)
>  r9:c05adffc r8:00000000 r7:80000000 r6:c5b5b010 r5:c05adffc r4:c5bed140
> [<c001b8e8>] (warn_slowpath_null) from [<bf3a0b78>] (cppi41_irq+0x1fc/0x230 [cppi41])
> [<bf3a097c>] (cppi41_irq [cppi41]) from [<c0055880>] (__handle_irq_event_percpu+0x8c/0x138)
>  r10:c05b4c2c r9:c05adffc r8:0000003a r7:c7b21c2c r6:00000000 r5:c05adffc
>  r4:c5bed140
> [<c00557f4>] (__handle_irq_event_percpu) from [<c0055950>] (handle_irq_event_percpu+0x24/0x60)
>  r10:bf401940 r9:00000000 r8:c7b21cb0 r7:00000000 r6:00000000 r5:c05adffc
>  r4:c05adffc
> [<c005592c>] (handle_irq_event_percpu) from [<c00559e0>] (handle_irq_event+0x54/0x8c)
>  r5:c05cac14 r4:c05adffc
> [<c005598c>] (handle_irq_event) from [<c0059044>] (handle_edge_irq+0x148/0x200)
>  r5:c05cac14 r4:c05adffc
> [<c0058efc>] (handle_edge_irq) from [<c00550d4>] (__handle_domain_irq+0x88/0x104)
>  r5:c05cac14 r4:00000862
> [<c005504c>] (__handle_domain_irq) from [<c0009020>] (asm_do_IRQ+0x20/0x24)
>  r9:c7b20000 r8:00000098 r7:c7b21ce4 r6:febfd000 r5:a0000013 r4:bf320058
> [<c0009000>] (asm_do_IRQ) from [<c000e680>] (__irq_svc+0x60/0xd8)
> Exception stack(0xc7b21cb0 to 0xc7b21cf8)
> 1ca0:                                     fee00000 fee00024 01000000 bf2cadd8
> 1cc0: bf2d9e00 fee00000 bf2d9de0 c5849010 00000098 c7b21f40 bf401940 c7b21d14
> 1ce0: c7b21d00 c7b21d00 bf320058 bf320058 a0000013 ffffffff
> [<bf320000>] (da8xx_musb_enable [da8xx]) from [<bf2cbf80>] (musb_start+0xe8/0x118 [musb_hdrc])
>  r5:fee00400 r4:c5848010
> [<bf2cbe98>] (musb_start [musb_hdrc]) from [<bf2d3aac>] (musb_gadget_start+0xcc/0x140 [musb_hdrc])
>  r9:c7b21f40 r8:60000013 r7:c711bb90 r6:c5848010 r5:c5849138 r4:c5848138
> [<bf2d39e0>] (musb_gadget_start [musb_hdrc]) from [<bf26227c>] (udc_bind_to_driver+0xb8/0xf0 [udc_core])
>  r9:c7b21f40 r8:bf262fac r7:bf4018b4 r6:00000000 r5:bf4018b4 r4:c7b52600
> [<bf2621c4>] (udc_bind_to_driver [udc_core]) from [<bf262714>] (usb_gadget_probe_driver+0xf8/0x144 [udc_core])
>  r7:bf4018b4 r6:00000000 r5:bf262fbc r4:c7b52600
> [<bf26261c>] (usb_gadget_probe_driver [udc_core]) from [<bf3d6444>] (usb_composite_probe+0xa8/0xd4 [libcomposite])
>  r9:c7b21f40 r8:00000001 r7:bf3d6960 r6:bf4018b4 r5:bf401678 r4:bf40188c
> [<bf3d639c>] (usb_composite_probe [libcomposite]) from [<bf403014>] (eth_driver_init+0x14/0x1c [g_ether])
>  r7:00000000 r6:00000000 r5:bf403000 r4:ffffe000
> [<bf403000>] (eth_driver_init [g_ether]) from [<c00096dc>] (do_one_initcall+0x44/0x17c)
> [<c0009698>] (do_one_initcall) from [<c0082b94>] (do_init_module+0x60/0x1b0)
>  r9:c7b21f40 r8:00000001 r7:00000000 r6:c70254e0 r5:bf40194c r4:bf401940
> [<c0082b34>] (do_init_module) from [<c0081ef4>] (load_module+0xe70/0xfd4)
>  r6:00000000 r5:bf40194c r4:00000000
> [<c0081084>] (load_module) from [<c008226c>] (SyS_finit_module+0xac/0xc0)
>  r10:00000000 r9:c7b20000 r8:c000a604 r7:0000017b r6:00028440 r5:00000005
>  r4:00000000
> [<c00821c0>] (SyS_finit_module) from [<c000a460>] (ret_fast_syscall+0x0/0x38)
>  r6:00000000 r5:00040000 r4:00000000
> ---[ end trace 3d9a1549a3b9c331 ]---
> ------------[ cut here ]------------
> WARNING: CPU: 0 PID: 467 at drivers/dma/cppi41.c:342 cppi41_irq+0x1c8/0x230 [cppi41]
> Modules linked in: usb_f_ecm g_ether(+) usb_f_rndis u_ether usb_f_ss_lb libcomposite configfs ofpart davinci_nand nand nand_ecc cppi41 mtd vpif_display tvp514x vpif_capture videobuf2_dma_contig videobuf2_memops videobuf2_v4l2 videobuf2_c]
> CPU: 0 PID: 467 Comm: modprobe Tainted: G        W       4.12.0-rc7-next-20170629-10695-g3fb8ba638d53 #76
> Hardware name: Generic DA850/OMAP-L138/AM18x
> Backtrace: 
> [<c000d794>] (dump_backtrace) from [<c000da38>] (show_stack+0x18/0x1c)
>  r7:00000009 r6:00000000 r5:bf3a19f0 r4:00000000
> [<c000da20>] (show_stack) from [<c043b310>] (dump_stack+0x20/0x28)
> [<c043b2f0>] (dump_stack) from [<c001b830>] (__warn+0xdc/0x104)
> [<c001b754>] (__warn) from [<c001b910>] (warn_slowpath_null+0x28/0x30)
>  r9:00000000 r8:00000000 r7:00000000 r6:c5b5b010 r5:c733f100 r4:0000001f
> [<c001b8e8>] (warn_slowpath_null) from [<bf3a0b44>] (cppi41_irq+0x1c8/0x230 [cppi41])
> [<bf3a097c>] (cppi41_irq [cppi41]) from [<c0055880>] (__handle_irq_event_percpu+0x8c/0x138)
>  r10:c05b4c2c r9:c05adffc r8:0000003a r7:c7b21c2c r6:00000000 r5:c05adffc
>  r4:c5bed140
> [<c00557f4>] (__handle_irq_event_percpu) from [<c0055950>] (handle_irq_event_percpu+0x24/0x60)
>  r10:bf401940 r9:00000000 r8:c7b21cb0 r7:00000000 r6:00000000 r5:c05adffc
>  r4:c05adffc
> [<c005592c>] (handle_irq_event_percpu) from [<c00559e0>] (handle_irq_event+0x54/0x8c)
>  r5:c05cac14 r4:c05adffc
> [<c005598c>] (handle_irq_event) from [<c0059044>] (handle_edge_irq+0x148/0x200)
>  r5:c05cac14 r4:c05adffc
> [<c0058efc>] (handle_edge_irq) from [<c00550d4>] (__handle_domain_irq+0x88/0x104)
>  r5:c05cac14 r4:00000862
> [<c005504c>] (__handle_domain_irq) from [<c0009020>] (asm_do_IRQ+0x20/0x24)
>  r9:c7b20000 r8:00000098 r7:c7b21ce4 r6:febfd000 r5:a0000013 r4:bf320058
> [<c0009000>] (asm_do_IRQ) from [<c000e680>] (__irq_svc+0x60/0xd8)
> Exception stack(0xc7b21cb0 to 0xc7b21cf8)
> 1ca0:                                     fee00000 fee00024 01000000 bf2cadd8
> 1cc0: bf2d9e00 fee00000 bf2d9de0 c5849010 00000098 c7b21f40 bf401940 c7b21d14
> 1ce0: c7b21d00 c7b21d00 bf320058 bf320058 a0000013 ffffffff
> [<bf320000>] (da8xx_musb_enable [da8xx]) from [<bf2cbf80>] (musb_start+0xe8/0x118 [musb_hdrc])
>  r5:fee00400 r4:c5848010
> [<bf2cbe98>] (musb_start [musb_hdrc]) from [<bf2d3aac>] (musb_gadget_start+0xcc/0x140 [musb_hdrc])
>  r9:c7b21f40 r8:60000013 r7:c711bb90 r6:c5848010 r5:c5849138 r4:c5848138
> [<bf2d39e0>] (musb_gadget_start [musb_hdrc]) from [<bf26227c>] (udc_bind_to_driver+0xb8/0xf0 [udc_core])
>  r9:c7b21f40 r8:bf262fac r7:bf4018b4 r6:00000000 r5:bf4018b4 r4:c7b52600
> [<bf2621c4>] (udc_bind_to_driver [udc_core]) from [<bf262714>] (usb_gadget_probe_driver+0xf8/0x144 [udc_core])
>  r7:bf4018b4 r6:00000000 r5:bf262fbc r4:c7b52600
> [<bf26261c>] (usb_gadget_probe_driver [udc_core]) from [<bf3d6444>] (usb_composite_probe+0xa8/0xd4 [libcomposite])
>  r9:c7b21f40 r8:00000001 r7:bf3d6960 r6:bf4018b4 r5:bf401678 r4:bf40188c
> [<bf3d639c>] (usb_composite_probe [libcomposite]) from [<bf403014>] (eth_driver_init+0x14/0x1c [g_ether])
>  r7:00000000 r6:00000000 r5:bf403000 r4:ffffe000
> [<bf403000>] (eth_driver_init [g_ether]) from [<c00096dc>] (do_one_initcall+0x44/0x17c)
> [<c0009698>] (do_one_initcall) from [<c0082b94>] (do_init_module+0x60/0x1b0)
>  r9:c7b21f40 r8:00000001 r7:00000000 r6:c70254e0 r5:bf40194c r4:bf401940
> [<c0082b34>] (do_init_module) from [<c0081ef4>] (load_module+0xe70/0xfd4)
>  r6:00000000 r5:bf40194c r4:00000000
> [<c0081084>] (load_module) from [<c008226c>] (SyS_finit_module+0xac/0xc0)
>  r10:00000000 r9:c7b20000 r8:c000a604 r7:0000017b r6:00028440 r5:00000005
>  r4:00000000
> [<c00821c0>] (SyS_finit_module) from [<c000a460>] (ret_fast_syscall+0x0/0x38)
>  r6:00000000 r5:00040000 r4:00000000
> ---[ end trace 3d9a1549a3b9c332 ]---
> cppi41_irq() q 31 desc c733f100
> IPv6: ADDRCONF(NETDEV_UP): usb0: link is not ready
> 
> g_ether gadget: high-speed config #1: CDC Ethernet (ECM)
> IPv6: ADDRCONF(NETDEV_CHANGE): usb0: link becomes ready
> ------------[ cut here ]------------
> WARNING: CPU: 0 PID: 461 at drivers/dma/cppi41.c:342 cppi41_irq+0x1c8/0x230 [cppi41]
> Modules linked in: usb_f_ecm g_ether(+) usb_f_rndis u_ether usb_f_ss_lb libcomposite configfs ofpart davinci_nand nand nand_ecc cppi41 mtd vpif_display tvp514x vpif_capture videobuf2_dma_contig videobuf2_memops videobuf2_v4l2 videobuf2_c]
> CPU: 0 PID: 461 Comm: syslog-ng Tainted: G        W       4.12.0-rc7-next-20170629-10695-g3fb8ba638d53 #76
> Hardware name: Generic DA850/OMAP-L138/AM18x
> Backtrace: 
> [<c000d794>] (dump_backtrace) from [<c000da38>] (show_stack+0x18/0x1c)
>  r7:00000009 r6:00000000 r5:bf3a19f0 r4:00000000
> [<c000da20>] (show_stack) from [<c043b310>] (dump_stack+0x20/0x28)
> [<c043b2f0>] (dump_stack) from [<c001b830>] (__warn+0xdc/0x104)
> [<c001b754>] (__warn) from [<c001b910>] (warn_slowpath_null+0x28/0x30)
>  r9:00000000 r8:00000000 r7:00000000 r6:c5b5b010 r5:c733f020 r4:00000018
> [<c001b8e8>] (warn_slowpath_null) from [<bf3a0b44>] (cppi41_irq+0x1c8/0x230 [cppi41])
> [<bf3a097c>] (cppi41_irq [cppi41]) from [<c0055880>] (__handle_irq_event_percpu+0x8c/0x138)
>  r10:c05b4c2c r9:c05adffc r8:0000003a r7:c5b3de4c r6:00000000 r5:c05adffc
>  r4:c5bed140
> [<c00557f4>] (__handle_irq_event_percpu) from [<c0055950>] (handle_irq_event_percpu+0x24/0x60)
>  r10:0003a500 r9:00000000 r8:c5b3ded0 r7:00000000 r6:c5b3dfb0 r5:c05adffc
>  r4:c05adffc
> [<c005592c>] (handle_irq_event_percpu) from [<c00559e0>] (handle_irq_event+0x54/0x8c)
>  r5:c05cac14 r4:c05adffc
> [<c005598c>] (handle_irq_event) from [<c0059044>] (handle_edge_irq+0x148/0x200)
>  r5:c05cac14 r4:c05adffc
> [<c0058efc>] (handle_edge_irq) from [<c00550d4>] (__handle_domain_irq+0x88/0x104)
>  r5:c05cac14 r4:00000862
> [<c005504c>] (__handle_domain_irq) from [<c0009020>] (asm_do_IRQ+0x20/0x24)
>  r9:c5b3c000 r8:c5b3dfb0 r7:c5b3df04 r6:febfd000 r5:20000013 r4:c001f2b0
> [<c0009000>] (asm_do_IRQ) from [<c000e680>] (__irq_svc+0x60/0xd8)
> Exception stack(0xc5b3ded0 to 0xc5b3df18)
> dec0:                                     00000000 c04f21b8 c05d03c0 20000013
> dee0: 00000000 00000004 00000000 c5b3c000 c5b3dfb0 00000000 0003a500 c5b3df64
> df00: c5b3df10 c5b3df20 c022fa30 c001f2b0 20000013 ffffffff
> [<c001f230>] (__do_softirq) from [<c001f7d0>] (irq_exit+0xdc/0x130)
>  r10:0003a500 r9:00000000 r8:c5b3dfb0 r7:00000000 r6:00000000 r5:c05cac14
>  r4:00000000
> [<c001f6f4>] (irq_exit) from [<c00550dc>] (__handle_domain_irq+0x90/0x104)
> [<c005504c>] (__handle_domain_irq) from [<c0009020>] (asm_do_IRQ+0x20/0x24)
>  r9:b5b02c10 r8:00053177 r7:0005317f r6:febfd000 r5:60000010 r4:476e8358
> [<c0009000>] (asm_do_IRQ) from [<c000ea70>] (__irq_usr+0x50/0xc0)
> Exception stack(0xc5b3dfb0 to 0xc5b3dff8)
> dfa0:                                     00000000 47ec1440 00727041 00000000
> dfc0: 000ae520 ffffffff b5b02c10 47ec143c 47ee9e04 b5b02c10 0003a500 b66b518c
> dfe0: 47b803e4 b66b50d8 47af9410 476e8358 60000010 ffffffff
> ---[ end trace 3d9a1549a3b9c333 ]---
> cppi41_irq() q 24 desc c733f020
> root at omapl138-lcdk:~# 
> root at omapl138-lcdk:~# g_ether gadget: high-speed config #1: CDC Ethernet (ECM)
>