Re: [PATCH] mtd: maps/physmap: fix oops in suspend/resume/shutdown ops

[Anton Vorontsov <cbouatmailru@gmail.com>]

On Mon, Feb 18, 2008 at 12:37:34AM +0300, Anton Vorontsov wrote:
> - - - -
> # reboot
> ...
> [   42.351266] Flash device refused suspend due to active operation (state 0)
> [   42.358195] Unable to handle kernel NULL pointer dereference at virtual address 00000078
> [   42.360060] pgd = c7d9c000
> [   42.362769] [00000078] *pgd=a7d8d031, *pte=00000000, *ppte=00000000
> [   42.372902] Internal error: Oops: 17 [#1]
> [   42.376911] Modules linked in:
> [   42.379980] CPU: 0    Not tainted  (2.6.25-rc2-10642-ge8f2594-dirty #73)
> [   42.380000] PC is at physmap_flash_shutdown+0x28/0x54
> ...
> [   42.380000] Backtrace:
> [   42.380000] [<c0130c1c>] (physmap_flash_shutdown+0x0/0x54) from [<c01207c0>] (platform_drv_shutdown+0x20/0x24)
> [   42.380000]  r5:28121969 r4:c0229e08
> [   42.380000] [<c01207a0>] (platform_drv_shutdown+0x0/0x24) from [<c011cd40>] (device_shutdown+0x60/0x88)
> [   42.380000] [<c011cce0>] (device_shutdown+0x0/0x88) from [<c003e8a4>] (kernel_restart_prepare+0x2c/0x3c)
> [   42.380000]  r4:00000000
> [   42.380000] [<c003e878>] (kernel_restart_prepare+0x0/0x3c) from [<c003ea00>] (kernel_restart+0x14/0x48)
> [   42.380000] [<c003e9ec>] (kernel_restart+0x0/0x48) from [<c003fdc0>] (sys_reboot+0xe8/0x1f8)
> [   42.380000]  r4:01234567
> [   42.380000] [<c003fcd8>] (sys_reboot+0x0/0x1f8) from [<c001aa00>] (ret_fast_syscall+0x0/0x2c)
> [   42.380000]  r7:00000058 r6:00000004 r5:00000001 r4:00000000
> [   42.380000] Code: 0a000009 e7953004 e1a00003 e1a0e00f (e593f078)
> [   42.650051] ---[ end trace 6d6c26a0fc3141de ]---
> Segmentation fault
> INIT: no more processes left in this runlevel
> - - - -
> 
> While looping for mtd[i]s, we should stop at the mtd[i] == NULL.
> 
> This patch also removes unnecessary "if (info)" checks:
> suspend/resume/shutdown ops are executed only if probe() is succeeded,
> so info is guaranteed to be !NULL.
> 
> Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>
> ---
>  drivers/mtd/maps/physmap.c |   15 +++++++--------
>  1 files changed, 7 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/mtd/maps/physmap.c b/drivers/mtd/maps/physmap.c
> index f00e04e..bc4649a 100644
> --- a/drivers/mtd/maps/physmap.c
> +++ b/drivers/mtd/maps/physmap.c
> @@ -202,9 +202,8 @@ static int physmap_flash_suspend(struct platform_device *dev, pm_message_t state
>  	int ret = 0;
>  	int i;
>  
> -	if (info)
> -		for (i = 0; i < MAX_RESOURCES; i++)
> -			ret |= info->mtd[i]->suspend(info->mtd[i]);
> +	for (i = 0; i < MAX_RESOURCES && info->mtd[i]; i++)
> +		ret |= info->mtd[i]->suspend(info->mtd[i]);
>  
>  	return ret;
>  }
> @@ -214,9 +213,9 @@ static int physmap_flash_resume(struct platform_device *dev)
>  	struct physmap_flash_info *info = platform_get_drvdata(dev);
>  	int i;
>  
> -	if (info)
> -		for (i = 0; i < MAX_RESOURCES; i++)
> -			info->mtd[i]->resume(info->mtd[i]);
> +	for (i = 0; i < MAX_RESOURCES && info->mtd[i]; i++)
> +		info->mtd[i]->resume(info->mtd[i]);
> +
>  	return 0;
>  }
>  
> @@ -225,8 +224,8 @@ static void physmap_flash_shutdown(struct platform_device *dev)
>  	struct physmap_flash_info *info = platform_get_drvdata(dev);
>  	int i;
>  
> -	for (i = 0; i < MAX_RESOURCES; i++)
> -		if (info && info->mtd[i]->suspend(info->mtd[i]) == 0)
> +	for (i = 0; i < MAX_RESOURCES && info->mtd[i]; i++)
> +		if (info->mtd[i]->suspend(info->mtd[i]) == 0)
>  			info->mtd[i]->resume(info->mtd[i]);
>  }
>  #else
> -- 
> 1.5.3.7
> 

Patch seem to be lost. Would be great to get this applied before
final 2.6.25...

Thanks,

-- 
Anton Vorontsov
email: cbouatmailru@gmail.com
irc://irc.freenode.net/bd2