Re: Badness at mm/backing-dev.c:179

Geert Uytterhoeven
2008-12-08T08:16:53Z

On Wed, 3 Dec 2008, Kay Sievers wrote:
> On Wed, Dec 3, 2008 at 13:07, Mark Jackson <mpfj@mimc.co.uk> wrote:
> > The following commit causes a "Badness at mm/backing-dev.c:179":-
> >
> > f1d0b063d993527754f062c589b73f125024d216 is first bad commit
> > commit f1d0b063d993527754f062c589b73f125024d216
> > Author: Kay Sievers <kay.sievers@vrfy.org>
> > Date: Tue Dec 2 10:31:50 2008 -0800
> >
> > bdi: register sysfs bdi device only once per queue
>
> > Below is the extract from dmesg:-
> >
> > ------------[ cut here ]------------
> > Badness at mm/backing-dev.c:179
>
> That's a known issue, and will not cause any harm besides printing
> this warning. Andrew added the warning to catch drivers who use one
> single request queue for multiple devices. Currently known are mtd and
> floppy (triggers only if you have more than one device per driver).
> The drivers need to be changed to use a separate queue per device, to
> get rid of this warning.

I guess this one (introduced after 2.6.28-rc7) is an incarnation of the same
issue?

WARNING: at mm/backing-dev.c:179 0x2069cb()
Modules linked in:
Call Trace: [<000273ee>] warn_on_slowpath+0x44/0x60
[<001be5b0>] mutex_lock+0x0/0x24
[<00075d1e>] ifind+0x16/0x5c
[<000a0844>] sysfs_ilookup_test+0x0/0x18
[<00075d92>] ilookup5+0x2e/0x38
[<000a0e70>] sysfs_addrm_finish+0x1c/0x200
[<000a047e>] sysfs_create_file+0x0/0x44
[<000a0432>] sysfs_add_file_mode+0x5a/0x84
[<000efc5a>] kobject_uevent_env+0x46/0x30c
[<000a047e>] sysfs_create_file+0x0/0x44
[<000a0478>] sysfs_add_file+0x1c/0x22
[<000eff30>] kobject_uevent+0x10/0x16
[<000e1332>] elv_register_queue+0x64/0x6e
[<000eff20>] kobject_uevent+0x0/0x16
[<000e450e>] blk_register_queue+0x56/0x94
[<00051684>] bdi_register+0x54/0x5e
[<000f4040>] sprintf+0x0/0x26
[<000516b4>] bdi_register_dev+0x26/0x2c
[<000e7e70>] add_disk+0xb8/0x12c
[<000e7db8>] add_disk+0x0/0x12c
[<0027e424>] atari_floppy_init+0x14c/0x6e4
[<0027e2d8>] atari_floppy_init+0x0/0x6e4
[<00002008>] do_one_initcall+0x0/0x19a
[<002781ce>] __alloc_bootmem+0x0/0x1a
[<00002024>] do_one_initcall+0x1c/0x19a
[<001be5b0>] mutex_lock+0x0/0x24
[<00075d1e>] ifind+0x16/0x5c
[<000a0844>] sysfs_ilookup_test+0x0/0x18
[<00075d92>] ilookup5+0x2e/0x38
[<000a0e70>] sysfs_addrm_finish+0x1c/0x200
[<002781ce>] __alloc_bootmem+0x0/0x1a
[<000a0432>] sysfs_add_file_mode+0x5a/0x84
[<001244aa>] sysdev_class_create_file+0x0/0x16
[<000a0478>] sysfs_add_file+0x1c/0x22
[<000a04bc>] sysfs_create_file+0x3e/0x44
[<001244bc>] sysdev_class_create_file+0x12/0x16
[<0027e102>] cpu_dev_init+0x4e/0x6c
[<0026eaa8>] kernel_init+0x6e/0xc2
[<0027e2d8>] atari_floppy_init+0x0/0x6e4
[<0026ea3a>] kernel_init+0x0/0xc2
[<00027902>] printk+0x0/0x1a
[<00002ada>] kernel_thread+0x3a/0x4e

---[ end trace 7d0e1e0e92952ce0 ]---

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds