SMP issues on ARM11 MPCore

[Uwe Kleine-König]

Hi Dirk,

On Thu, Jan 07, 2010 at 02:45:11PM +0100, Dirk Behme wrote:
> >  Unable to handle kernel NULL pointer dereference at virtual address 00000000
> >  pgd = cc37c000
> >  [00000000] *pgd=8c38f031, *pte=00000000, *ppte=00000000
> >  Internal error: Oops: 17 [#1] SMP
> >  last sysfs file:
> >  Modules linked in: [last unloaded: module]
> >  CPU: 0    Not tainted  (2.6.32-00012-g89b993e-dirty #17)
> >  PC is at strcmp+0x8/0x34
> >  LR is at sysfs_find_dirent+0x18/0x38
> >  pc : [<c094bd8c>]    lr : [<c08ede4c>]    psr: a0000013
> >  sp : cc26bef8  ip : 00000000  fp : 00000000
> >  r10: 40025000  r9 : cc26a000  r8 : 00000880
> >  r7 : cc26bf44  r6 : 00000000  r5 : 00000000  r4 : cc326428
> >  r3 : 000009b3  r2 : 00000000  r1 : 00000000  r0 : 00000000
> >  Flags: NzCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment user
> >  Control: 08c5787d  Table: 8c37c00a  DAC: 00000015
> >  Process rmmod (pid: 378, stack limit = 0xcc26a270)
> >  Stack: (0xcc26bef8 to 0xcc26c000)
> >  bee0:                                                       cc3263f8 00000000
> >  bf00: 00000000 c08ec918 cc3263f8 00000000 00000000 00000000 00000000 ccd961e0
> >  bf20: 00000000 c087de50 bf000074 bf000074 00000000 c087e214 00000000 c087e550
> >  bf40: 00000001 75646f6d cc00656c cc37d000 cc25ba20 cc25ba64 cc25ba54 00000000
> >  bf60: 40025000 00000000 40025000 00000001 cc26a000 4002501c bef869c4 0089e8e8
> >  bf80: bf000074 00000880 cc26bf8c 00000000 be00656c 400256c0 00000000 00000081
> >  bfa0: c0842224 c08420a0 be00656c 400256c0 bef86b80 00000880 00000000 75646f6d
> >  bfc0: be00656c 400256c0 00000000 00000081 00000059 00000000 40025000 00000000
> >  bfe0: bef86b80 bef86b70 00012fe0 400e7740 60000010 bef86b80 00000000 00000000
> >  [<c094bd8c>] (strcmp+0x8/0x34) from [<c08ede4c>] (sysfs_find_dirent+0x18/0x38)
> >  [<c08ede4c>] (sysfs_find_dirent+0x18/0x38) from [<c08ec918>]
> > (sysfs_hash_and_remove+0x28/0x60)
> >  [<c08ec918>] (sysfs_hash_and_remove+0x28/0x60) from [<c087de50>]
> > (free_notes_attrs+0x2c/0x4c)
> >  [<c087de50>] (free_notes_attrs+0x2c/0x4c) from [<c087e214>]
> > (free_module+0x2c/0xdc)
> >  [<c087e214>] (free_module+0x2c/0xdc) from [<c087e550>]
> > (sys_delete_module+0x214/0x250)
> >  [<c087e550>] (sys_delete_module+0x214/0x250) from [<c08420a0>]
> > (ret_fast_syscall+0x0/0x2c)
> 
> Debugging of above call stack shows:
> 
> strcmp() fails due to both parameters, cs and ct being NULL.
> 
> Function free_module() gets 'struct module *mod' as parameter. This
> has an element
> 
> mod->notes_attrs->attrs[0].attr.name
> 
> In case of module's init and exit function are _both_ marked with
> __init/__exit, this name is NULL. This is then parsed down by above
> call stack and let strcmp() fail.
> 
> In case init and/or exit function in above module don't have
> __init/__exit, name is a valid pointer.
> 
> Any idea what might cause this?
> 
> Many thanks and best regards
does

	http://svn.debian.org/wsvn/kernel/dists/trunk/linux-2.6/debian/patches/bugfix/all/modules-Skip-empty-section-notes.patch

help you?

Best regards
Uwe

-- 
Pengutronix e.K.                              | Uwe Kleine-König            |
Industrial Linux Solutions                    | http://www.pengutronix.de/  |