Re: omapdss: Division by zero in kernel

Pali Rohár
2015-08-18T14:00:08Z

On Tuesday 28 July 2015 13:56:02 Pali Rohár wrote:
> On Friday 24 July 2015 18:03:42 Pali Rohár wrote:
> > Hello,
> >
> > when on N900 (real HW or qemu) I run this command
> >
> > / # echo 0 > /sys/devices/platform/omapdss/overlay0/enabled && echo 0 > /sys/class/graphics/fb0/size
> >
> > then kernel crash with this error message
> >
> > / # [ 29.904113] Division by zero in kernel.
> > ** 3375 printk messages dropped ** [ 29.963836] [<c01e0008>] (__aeabi_uidivmod) from [<c022071c>]
> > (cfb_imageblit+0xac/0x464)
> > ** 8426 printk messages dropped ** [ 30.111083] [<c02187a4>] (fbcon_redraw.isra.12) from [<c0218ed0>]
> > (fbcon_scroll+0x6a0/0xcbc)
> > ** 8380 printk messages dropped ** [ 30.258209] [<c02187a4>] (fbcon_redraw.isra.12) from [<c0218ed0>]
> > (fbcon_scroll+0x6a0/0xcbc)
> > ** 7813 printk messages dropped ** [ 30.400054] [<c02187a4>] (fbcon_redraw.isra.12) from [<c0218ed0>]
> > (fbcon_scroll+0x6a0/0xcbc)
> > ** 7666 printk messages dropped ** [ 30.538391] [<c02187a4>] (fbcon_redraw.isra.12) from [<c0218ed0>]
> > (fbcon_scroll+0x6a0/0xcbc)
> > ** 7687 printk messages dropped ** [ 30.676544] [<c02187a4>] (fbcon_redraw.isra.12) from [<c0218ed0>]
> > (fbcon_scroll+0x6a0/0xcbc)
> > ** 7960 printk messages dropped ** [ 30.819915] [<c02187a4>] (fbcon_redraw.isra.12) from [<c0218ed0>]
> > (fbcon_scroll+0x6a0/0xcbc)
> > ** 8317 printk messages dropped ** [ 30.966979] [<c02187a4>] (fbcon_redraw.isra.12) from [<c0218ed0>]
> > (fbcon_scroll+0x6a0/0xcbc)
> > ** 8590 printk messages dropped ** [ 31.122528] [<c02187a4>] (fbcon_redraw.isra.12) from [<c0218ed0>]
> > (fbcon_scroll+0x6a0/0xcbc)
> > ** 8885 printk messages dropped ** [ 31.287658] [<c0218ed0>] (fbcon_scroll) from [<c025af90>] (scrup+0x60/0x128)
> > ** 9408 printk messages dropped ** [ 31.461425] [<c02187a4>] (fbcon_redraw.isra.12) from [<c0218ed0>]
> > (fbcon_scroll+0x6a0/0xcbc)
> > ** 9787 printk messages dropped ** [ 31.644287] [<c02187e8>] (fbcon_redraw.isra.12) from [<c0218ed0>]
> > (fbcon_scroll+0x6a0/0xcbc)
> > ** 10081 printk messages dropped ** [ 31.833984] [<c02187a4>] (fbcon_redraw.isra.12) from [<c0218ed0>]
> > (fbcon_scroll+0x6a0/0xcbc)
> > ** 10501 printk messages dropped ** [ 32.031066] [<c02187a4>] (fbcon_redraw.isra.12) from [<c0218ed0>]
> > (fbcon_scroll+0x6a0/0xcbc)
> > ** 10816 printk messages dropped ** [ 32.233001] [<c02187a4>] (fbcon_redraw.isra.12) from [<c0218ed0>]
> > (fbcon_scroll+0x6a0/0xcbc)
> > ** 10900 printk messages dropped ** [ 32.440490] [<c02187a4>] (fbcon_redraw.isra.12) from [<c0218ed0>]
> > (fbcon_scroll+0x6a0/0xcbc)
> > ** 10837 printk messages dropped ** [ 32.645233] [<c02187a4>] (fbcon_redraw.isra.12) from [<c0218ed0>]
> > (fbcon_scroll+0x6a0/0xcbc)
> > ** 10837 printk messages dropped ** [ 32.848999] [<c02187a4>] (fbcon_redraw.isra.12) from [<c0218ed0>]
> > (fbcon_scroll+0x6a0/0xcbc)
> > ** 10837 printk messages dropped ** [ 33.053833] [<c02187a4>] (fbcon_redraw.isra.12) from [<c0218ed0>]
> > (fbcon_scroll+0x6a0/0xcbc)
> > ** 10838 printk messages dropped ** [ 33.258361] [<c0218ed0>] (fbcon_scroll) from [<c025af90>] (scrup+0x60/0x128)
> >
> > I suspect that problem is in omapdss.
> >
> > I do not know if size 0 make sense, but Maemo userspace is calling above
> > commands and on Nokia's 2.6.28 kernel there is no crash or error message.
> >
> > IMHO Division by zero in kernel should not be there even if userspace
> > call "incorrect" command.
> >
>
> PING! Any idea what to do with Division by zero in kernel?
>

PING again! Can somebody look at this Division by zero in kernel?