From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pali =?utf-8?B?Um9ow6Fy?= Subject: Re: omapdss: Division by zero in kernel Date: Tue, 18 Aug 2015 16:00:02 +0200 Message-ID: <20150818140002.GU32236@pali> References: <201507241803.42891@pali> <20150728115602.GL13765@pali> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Content-Disposition: inline In-Reply-To: <20150728115602.GL13765@pali> Sender: linux-kernel-owner@vger.kernel.org To: Tomi Valkeinen , Jean-Christophe Plagniol-Villard , Jyri Sarha Cc: linux-omap@vger.kernel.org, linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org, Pavel Machek , Sebastian Reichel , Aaro Koskinen , Tony Lindgren , Nishanth Menon List-Id: linux-omap@vger.kernel.org On Tuesday 28 July 2015 13:56:02 Pali Roh=C3=A1r wrote: > On Friday 24 July 2015 18:03:42 Pali Roh=C3=A1r wrote: > > Hello, > >=20 > > when on N900 (real HW or qemu) I run this command > >=20 > > / # echo 0 > /sys/devices/platform/omapdss/overlay0/enabled && echo= 0 > /sys/class/graphics/fb0/size > >=20 > > then kernel crash with this error message > >=20 > > / # [ 29.904113] Division by zero in kernel. > > ** 3375 printk messages dropped ** [ 29.963836] [] (__a= eabi_uidivmod) from []=20 > > (cfb_imageblit+0xac/0x464) > > ** 8426 printk messages dropped ** [ 30.111083] [] (fbc= on_redraw.isra.12) from []=20 > > (fbcon_scroll+0x6a0/0xcbc) > > ** 8380 printk messages dropped ** [ 30.258209] [] (fbc= on_redraw.isra.12) from []=20 > > (fbcon_scroll+0x6a0/0xcbc) > > ** 7813 printk messages dropped ** [ 30.400054] [] (fbc= on_redraw.isra.12) from []=20 > > (fbcon_scroll+0x6a0/0xcbc) > > ** 7666 printk messages dropped ** [ 30.538391] [] (fbc= on_redraw.isra.12) from []=20 > > (fbcon_scroll+0x6a0/0xcbc) > > ** 7687 printk messages dropped ** [ 30.676544] [] (fbc= on_redraw.isra.12) from []=20 > > (fbcon_scroll+0x6a0/0xcbc) > > ** 7960 printk messages dropped ** [ 30.819915] [] (fbc= on_redraw.isra.12) from []=20 > > (fbcon_scroll+0x6a0/0xcbc) > > ** 8317 printk messages dropped ** [ 30.966979] [] (fbc= on_redraw.isra.12) from []=20 > > (fbcon_scroll+0x6a0/0xcbc) > > ** 8590 printk messages dropped ** [ 31.122528] [] (fbc= on_redraw.isra.12) from []=20 > > (fbcon_scroll+0x6a0/0xcbc) > > ** 8885 printk messages dropped ** [ 31.287658] [] (fbc= on_scroll) from [] (scrup+0x60/0x128) > > ** 9408 printk messages dropped ** [ 31.461425] [] (fbc= on_redraw.isra.12) from []=20 > > (fbcon_scroll+0x6a0/0xcbc) > > ** 9787 printk messages dropped ** [ 31.644287] [] (fbc= on_redraw.isra.12) from []=20 > > (fbcon_scroll+0x6a0/0xcbc) > > ** 10081 printk messages dropped ** [ 31.833984] [] (fb= con_redraw.isra.12) from []=20 > > (fbcon_scroll+0x6a0/0xcbc) > > ** 10501 printk messages dropped ** [ 32.031066] [] (fb= con_redraw.isra.12) from []=20 > > (fbcon_scroll+0x6a0/0xcbc) > > ** 10816 printk messages dropped ** [ 32.233001] [] (fb= con_redraw.isra.12) from []=20 > > (fbcon_scroll+0x6a0/0xcbc) > > ** 10900 printk messages dropped ** [ 32.440490] [] (fb= con_redraw.isra.12) from []=20 > > (fbcon_scroll+0x6a0/0xcbc) > > ** 10837 printk messages dropped ** [ 32.645233] [] (fb= con_redraw.isra.12) from []=20 > > (fbcon_scroll+0x6a0/0xcbc) > > ** 10837 printk messages dropped ** [ 32.848999] [] (fb= con_redraw.isra.12) from []=20 > > (fbcon_scroll+0x6a0/0xcbc) > > ** 10837 printk messages dropped ** [ 33.053833] [] (fb= con_redraw.isra.12) from []=20 > > (fbcon_scroll+0x6a0/0xcbc) > > ** 10838 printk messages dropped ** [ 33.258361] [] (fb= con_scroll) from [] (scrup+0x60/0x128) > >=20 > > I suspect that problem is in omapdss. > >=20 > > 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 me= ssage. > >=20 > > IMHO Division by zero in kernel should not be there even if userspa= ce > > call "incorrect" command. > >=20 >=20 > PING! Any idea what to do with Division by zero in kernel? >=20 PING again! Can somebody look at this Division by zero in kernel? --=20 Pali Roh=C3=A1r pali.rohar@gmail.com