Re: [PATCH] ASoC: fsl_ssi: free irq before irq_dispose_mapping()

Markus Pargmann
2014-12-01T06:51:01Z

[-- Attachment #1: Type: text/plain, Size: 4456 bytes --]

Hi,

On Mon, Dec 01, 2014 at 11:50:51AM +0900, Jiada Wang wrote:
> irq_dispose_mapping() in turns calls unregister_irq_proc(),
> which will remove irq proc entry, if IRQ is not freed
> before calling of irq_dispose_mapping(), then it will cause
> kernel warning.
>
> By free IRQ before irq_dispose_mapping(), this patch fix
> the following kernel warning found when remove of fsl_ssi driver:
>
> [ 31.515336] ------------[ cut here ]------------
> [ 31.520091] WARNING: CPU: 2 PID: 434 at fs/proc/generic.c:521 remove_proc_entry+0x14c/0x16c()
> [ 31.528708] remove_proc_entry: removing non-empty directory 'irq/79', leaking at least '202c000.ss'
> [ 31.537911] Modules linked in: snd_soc_wm8962 snd_soc_imx_wm8962 snd_soc_fsl_ssi(-) evbug
> [ 31.546249] CPU: 2 PID: 434 Comm: rmmod Not tainted 3.18.0-rc6-00028-g3314bf6-dirty #1
> [ 31.554235] Backtrace:
> [ 31.556816] [<80011ea8>] (dump_backtrace) from [<80012044>] (show_stack+0x18/0x1c)
> [ 31.564416] r6:80142c88 r5:00000000 r4:00000000 r3:00000000
> [ 31.570267] [<8001202c>] (show_stack) from [<806980ec>] (dump_stack+0x88/0xa4)
> [ 31.577588] [<80698064>] (dump_stack) from [<80029d78>] (warn_slowpath_common+0x70/0x94)
> [ 31.585711] r5:00000009 r4:bb61fd90
> [ 31.589423] [<80029d08>] (warn_slowpath_common) from [<80029e40>] (warn_slowpath_fmt+0x38/0x40)
> [ 31.598187] r8:bb61fdfe r7:be05d76d r6:be05d9a8 r5:00000002 r4:be05d700
> [ 31.605054] [<80029e0c>] (warn_slowpath_fmt) from [<80142c88>] (remove_proc_entry+0x14c/0x16c)
> [ 31.613709] r3:806a79c0 r2:808229a0
> [ 31.617371] [<80142b3c>] (remove_proc_entry) from [<80070380>] (unregister_irq_proc+0x94/0xb8)
> [ 31.625989] r10:00000000 r8:8000ede4 r7:80955f2c r6:0000004f r5:8118e738 r4:be00af00
> [ 31.633952] [<800702ec>] (unregister_irq_proc) from [<80069dac>] (free_desc+0x2c/0x64)
> [ 31.641898] r6:0000004f r5:80955f38 r4:be00af00
> [ 31.646604] [<80069d80>] (free_desc) from [<80069e68>] (irq_free_descs+0x4c/0x8c)
> [ 31.654092] r7:00000081 r6:00000001 r5:0000004f r4:00000001
> [ 31.659863] [<80069e1c>] (irq_free_descs) from [<8006fc3c>] (irq_dispose_mapping+0x40/0x5c)
> [ 31.668247] r6:be17b844 r5:be17b800 r4:0000004f r3:802c5ec0
> [ 31.673998] [<8006fbfc>] (irq_dispose_mapping) from [<7f004ea4>] (fsl_ssi_remove+0x58/0x70 [snd_so)
> [ 31.683948] r4:bb5bba10 r3:00000001
> [ 31.687618] [<7f004e4c>] (fsl_ssi_remove [snd_soc_fsl_ssi]) from [<803720a0>] (platform_drv_remove)
> [ 31.697564] r5:7f0064f8 r4:be17b810
> [ 31.701195] [<80372080>] (platform_drv_remove) from [<80370494>] (__device_release_driver+0x78/0xc)
> [ 31.710361] r5:7f0064f8 r4:be17b810
> [ 31.713987] [<8037041c>] (__device_release_driver) from [<80370d20>] (driver_detach+0xbc/0xc0)
> [ 31.722631] r5:7f0064f8 r4:be17b810
> [ 31.726259] [<80370c64>] (driver_detach) from [<80370304>] (bus_remove_driver+0x54/0x98)
> [ 31.734382] r6:00000800 r5:00000000 r4:7f0064f8 r3:bb67f500
> [ 31.740149] [<803702b0>] (bus_remove_driver) from [<80371398>] (driver_unregister+0x30/0x50)
> [ 31.748617] r4:7f0064f8 r3:bd9f7080
> [ 31.752245] [<80371368>] (driver_unregister) from [<80371f3c>] (platform_driver_unregister+0x14/0x)
> [ 31.761498] r4:7f00655c r3:7f005a70
> [ 31.765130] [<80371f28>] (platform_driver_unregister) from [<7f005a84>] (fsl_ssi_driver_exit+0x14/)
> [ 31.776147] [<7f005a70>] (fsl_ssi_driver_exit [snd_soc_fsl_ssi]) from [<8008ed80>] (SyS_delete_mod)
> [ 31.786553] [<8008ec64>] (SyS_delete_module) from [<8000ec20>] (ret_fast_syscall+0x0/0x48)
> [ 31.794824] r6:00c46d18 r5:00000800 r4:00c46d18
> [ 31.799530] ---[ end trace 954e8a3a15379e52 ]---
>
> Moreover replace devm_request_irq() with request_irq() since there is
> no need to use it as now driver always frees IRQ manually.

devm_request_irq() is used by other drivers too, this should not be a
problem. Looking at the code it seems that irq_dispose_mapping may not
be necessary with devm_request_irq(). So I think it would be better to
remove irq_dispose_mapping() instead.

Best Regards,

Markus Pargmann

--
Pengutronix e.K. | |
Industrial Linux Solutions | http://www.pengutronix.de/ |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 836 bytes --]