From mboxrd@z Thu Jan  1 00:00:00 1970
Date: Fri, 9 Mar 2018 14:28:21 -0800
From: Greg KH <greg@kroah.com>
To: Pavel Machek <pavel@ucw.cz>
Cc: pali.rohar@gmail.com, sre@kernel.org,
	kernel list <linux-kernel@vger.kernel.org>,
	linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
	linux-omap@vger.kernel.org, tony@atomide.com, khilman@kernel.org,
	aaro.koskinen@iki.fi, ivo.g.dimitrov.75@gmail.com,
	patrikbachan@gmail.com, serge@hallyn.com, abcloriens@gmail.com,
	clayton@craftyguy.net, martijn@brixit.nl,
	sakari.ailus@linux.intel.com,
	Filip =?utf-8?Q?Matijevi=C4=87?= <filip.matijevic.pz@gmail.com>,
	security@kernel.org, jic23@kernel.org, knaack.h@gmx.de,
	lars@metafoo.de, pmeerw@pmeerw.net, linux-iio@vger.kernel.org
Subject: Re: Nokia N900: v4.16-rc4: oops in iio when grepping sysfs
Message-ID: <20180309222821.GA16973@kroah.com>
References: <20180309221220.GA15272@amd>
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On Fri, Mar 09, 2018 at 11:12:21PM +0100, Pavel Machek wrote:
> Hi!
> 
> Hmm. Looks like there's a lot of fun to be had with sysfs.
> 
> 								Pavel
> 
> 
> pavel@n900:~$ uname -a
> Linux n900 4.16.0-rc4-59690-g7f84626-dirty #543 Thu Mar 8 19:53:30 CET
> 2018 armv7l GNU/Linux
> 
> [  306.402496] bq2415x: command Timer reset
> [  312.761322] adp1653 2-0030: Read Addr:03 Val:00 ok
> [  313.264129] Unable to handle kernel NULL pointer dereference at
> virtual address 00000
> 000
> [  313.272308] pgd = 01336620
> [  313.275146] [00000000] *pgd=800af831, *pte=00000000, *ppte=00000000
> [  313.281463] Internal error: Oops: 80000007 [#1] ARM
> [  313.286376] Modules linked in:
> [  313.289459] CPU: 0 PID: 3584 Comm: grep Tainted: G        W
> 4.16.0-rc4-59690-g
> 7f84626-dirty #543
> [  313.298919] Hardware name: Nokia RX-51 board
> [  313.303222] PC is at   (null)
> [  313.306213] LR is at iio_ev_state_show+0x38/0x54
> [  313.310852] pc : [<00000000>]    lr : [<c05d69c0>]    psr: a0000013
> [  313.317169] sp : c7b47e70  ip : c087bb24  fp : 00000001
> [  313.322418] r10: cb19e000  r9 : c0857220  r8 : 00001000
> [  313.327667] r7 : 00000fff  r6 : cb711c80  r5 : cb19e000  r4 :
> 00000000
> [  313.334228] r3 : 00000001  r2 : 00000000  r1 : c087b4dc  r0 :
> ce584800
> [  313.340789] Flags: NzCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM
> Segment none
> [  313.347991] Control: 10c5387d  Table: 87bec019  DAC: 00000051
> [  313.353759] Process grep (pid: 3584, stack limit = 0xc4e45eab)
> [  313.359619] Stack: (0xc7b47e70 to 0xc7b48000)
> [  313.364013] 7e60:                                     c05d6988
> cb711b00 ce585c00 c0450d68
> [  313.471038] [<c05d69c0>] (iio_ev_state_show) from [<c0450d68>]
> (dev_attr_show+0x1c/0x4c)
> [  313.479187] [<c0450d68>] (dev_attr_show) from [<c023f934>]
> (sysfs_kf_seq_show+0x90/0x108)
> [  313.487426] [<c023f934>] (sysfs_kf_seq_show) from [<c023e2f8>]
> (kernfs_seq_show+0x24/0x28)
> [  313.495758] [<c023e2f8>] (kernfs_seq_show) from [<c01fc954>]
> (seq_read+0x1dc/0x500)
> [  313.503479] [<c01fc954>] (seq_read) from [<c01d9f80>]
> (__vfs_read+0x2c/0x120)
> [  313.510681] [<c01d9f80>] (__vfs_read) from [<c01da0fc>]
> (vfs_read+0x88/0x114)
> [  313.517852] [<c01da0fc>] (vfs_read) from [<c01da584>]
> (SyS_read+0x40/0x8c)
> [  313.524780] [<c01da584>] (SyS_read) from [<c0101000>]
> (ret_fast_syscall+0x0/0x54)
> [  313.532318] Exception stack(0xc7b47fa8 to 0xc7b47ff0)
> [  313.537414] 7fa0:                   00035330 00042000 00000003
> 00042000 00008000 00008000
> 

What file are you opening to cause this?

thanks,

greg k-h