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

["Jörn Engel" <joern@logfs.org>]

On Fri, 14 March 2008 03:52:09 +0300, Anton Vorontsov wrote:
> 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...

Ooh!  There has been another patch for this problem, but yours is much
better.

Reviewed-By: Joern Engel <joern@logfs.org>

David, please apply this instead of Arnaud's or mine.

Jörn

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