Re: [PATCH] spi: Fix rmmod module issue

[Grant Likely <grant.likely@secretlab.ca>]

On Wed, Dec 22, 2010 at 09:57:47PM +0900, Tomoya MORINAGA wrote:
> It seems when spi_unregister_master is called,
> device_unregister is called 2 times.

This should be fixed in mainline now.  Can you please retest?

Thanks,
g.

> 
> Fix the following issue when removes SPI module.
> [ 1355.220625] BUG: unable to handle kernel NULL pointer dereference at 0000001c
> [ 1355.220642] IP: [<c10fc551>] sysfs_find_dirent+0xa/0x3a
> [ 1355.220662] *pde = 00000000
> [ 1355.220671] Oops: 0000 [#1] SMP
> [ 1355.220679] last sysfs file: /sys/power/state
> [ 1355.220688] Modules linked in: spi_topcliff_pch(-) spidev
> [ 1355.220700]
> [ 1355.220710] Pid: 3838, comm: rmmod Not tainted 2.6.37-rc6+ #7 To be filled by O.E.M./To be filled by O.E.M.
> [ 1355.220721] EIP: 0060:[<c10fc551>] EFLAGS: 00010286 CPU: 1
> [ 1355.220730] EIP is at sysfs_find_dirent+0xa/0x3a
> [ 1355.220739] EAX: 00000000 EBX: c14a2d38 ECX: c14a2d38 EDX: 00000000
> [ 1355.220748] ESI: 00000000 EDI: c14a2d38 EBP: f6605e60 ESP: f6605e54
> [ 1355.220757]  DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
> [ 1355.220767] Process rmmod (pid: 3838, ti=f6604000 task=f1281d40 task.ti=f6604000)
> [ 1355.220774] Stack:
> [ 1355.220779]  c14a2d38 00000000 00000000 f6605e74 c10fc5a2 f124ae00 f124ae08 c1643080
> [ 1355.220801]  f6605e88 c10fdfd4 f124ae00 00000001 f124a200 f6605e90 c1211184 f6605ea4
> [ 1355.220822]  c120c9d4 f124ae00 00000001 000001f4 f6605eb0 c120cafe f124ae00 f6605ebc
> [ 1355.220844] Call Trace:
> [ 1355.220856]  [<c10fc5a2>] ? sysfs_get_dirent+0x21/0x39
> [ 1355.220868]  [<c10fdfd4>] ? sysfs_remove_group+0x1a/0x85
> [ 1355.220881]  [<c1211184>] ? dpm_sysfs_remove+0x10/0x12
> [ 1355.220894]  [<c120c9d4>] ? device_del+0x31/0x150
> [ 1355.220906]  [<c120cafe>] ? device_unregister+0xb/0x15
> [ 1355.220917]  [<c1244428>] ? spi_unregister_master+0x54/0x57
> [ 1355.220932]  [<f80c95e7>] ? pch_spi_remove+0x89/0xb6 [spi_topcliff_pch]
> [ 1355.220946]  [<c11a0286>] ? pci_device_remove+0x19/0x39
> [ 1355.220959]  [<c120e6d9>] ? __device_release_driver+0x58/0x8e
> [ 1355.220971]  [<c120e76c>] ? driver_detach+0x5d/0x7b
> [ 1355.220983]  [<c120dc81>] ? bus_remove_driver+0x6c/0x92
> [ 1355.220995]  [<c120eb84>] ? driver_unregister+0x4d/0x54
> [ 1355.221007]  [<c11a0454>] ? pci_unregister_driver+0x2d/0x6a
> [ 1355.221019]  [<f80ca095>] ? pch_spi_exit+0xd/0x1b [spi_topcliff_pch]
> [ 1355.221020]  [<c105ab7b>] ? sys_delete_module+0x180/0x1d8
> [ 1355.221020]  [<c10a7900>] ? __vma_link_file+0x3d/0x61
> [ 1355.221020]  [<c10bfbea>] ? path_put+0xe/0x23
> [ 1355.221020]  [<c100290c>] ? sysenter_do_call+0x12/0x22
> [ 1355.221020] Code: 89 c3 74 18 8b 00 85 c0 75 0f ba b7 00 00 00 b8 c3 5a 58 c1 e8 10 4b f3 ff f0 ff 03 89 d8 5b 5d c3 55 89 e5 57 89 cf 56 89 d6 53 <8b> 58 1c eb 20 85 f6 74 0b 8
> b 43 14 85 c0 74 04 39 f0 75 0e 8b
> [ 1355.221020] EIP: [<c10fc551>] sysfs_find_dirent+0xa/0x3a SS:ESP 0068:f6605e54
> [ 1355.221020] CR2: 000000000000001c
> [ 1355.221237] ---[ end trace ac3358f2d325b0b5 ]---
> 
> Signed-off-by: Tomoya MORINAGA <tomoya-linux@dsn.okisemi.com>
> ---
>  drivers/spi/spi.c |    1 -
>  1 files changed, 0 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
> index 709c836..3c8ff6f 100644
> --- a/drivers/spi/spi.c
> +++ b/drivers/spi/spi.c
> @@ -586,7 +586,6 @@ void spi_unregister_master(struct spi_master *master)
>  
>  	dummy = device_for_each_child(master->dev.parent, &master->dev,
>  					__unregister);
> -	device_unregister(&master->dev);
>  }
>  EXPORT_SYMBOL_GPL(spi_unregister_master);
>  
> -- 
> 1.6.0.6
>