Re: [3.0-git16] Oops at driver_uevent_store().

Adrian Bunk
2011-08-04T08:40:33Z

On Thu, Aug 04, 2011 at 01:47:11AM -0400, Arnaud Lacombe wrote:
> Hi,
>
> [Added Adrian Bunk to the Cc: list]

Thanks.

> 2011/8/3 Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>:
>...
> commit 74b9a297866d0416edd0be5014cb0810de049c6a
> Author: Adrian Bunk <bunk@stusta.de>
> Date: Mon Mar 26 21:32:27 2007 -0800
>
> [PATCH] drivers/eisa/pci_eisa.c:pci_eisa_init() should be init
>
> WARNING: drivers/built-in.o - Section mismatch: reference to
> .init.text:eisa_root_register from .text between 'pci_eisa_init' (at
> offset 0xabf670) and 'virtual_eisa_release'
>
> AFAIK a PCI to EISA bridge isn't anything hotpluggable, so
> pci_eisa_init() can become __init.
>
> Signed-off-by: Adrian Bunk <bunk@stusta.de>
> Cc: Greg KH <greg@kroah.com>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
>
>
> To gain a few bytes, 'pci_eisa_init' is freed, but its reference is
> kept in `pci_eisa_driver' which triggers the warning. The commit log
> points out that PCI to EISA should not be hotpluggable, so it is not
> expected to be ever executed again (which would trigger a crash).

This was not for gaining a few bytes, and I'm not exactly seeing why I'm
to blame here, since my patch is invariant to what your patch does:

Calling pci_eisa_init outside of __init:
- might have crashed before my patch and
- after my patch and
- after your patch
since eisa_root_register() is __init.

> Marking `pci_eisa_driver' as __refdata fix the warning and leave the
> struct untouched:
>
> diff --git a/drivers/eisa/pci_eisa.c b/drivers/eisa/pci_eisa.c
> index 30da70d..cdae207 100644
> --- a/drivers/eisa/pci_eisa.c
> +++ b/drivers/eisa/pci_eisa.c
> @@ -45,13 +45,13 @@ static int __init pci_eisa_init(struct pci_dev *pdev,
> return 0;
> }
>
> -static struct pci_device_id __initdata pci_eisa_pci_tbl[] = {
> +static struct pci_device_id pci_eisa_pci_tbl[] = {
> { PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID,
> PCI_CLASS_BRIDGE_EISA << 8, 0xffff00, 0 },
> { 0, }
> };
>
> -static struct pci_driver __initdata pci_eisa_driver = {
> +static struct pci_driver __refdata pci_eisa_driver = {
> .name = "pci_eisa",
> .id_table = pci_eisa_pci_tbl,
> .probe = pci_eisa_init,

So the commit that broke it was not mine, but

commit 005bdad7b80ac017ca21d795639d4214b9844a84
Author: Arnaud Lacombe <lacombar@gmail.com>
Date: Mon Jul 25 17:13:04 2011 -0700

eisa/pci_eisa.c: fix section mismatch

Fixes

WARNING: vmlinux.o(.data+0x15d3ac): Section mismatch in reference from the
The variable pci_eisa_driver references the function __init pci_eisa_init(
If the reference is valid then annotate the variable with __init* or __ref
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

Signed-off-by: Arnaud Lacombe <lacombar@gmail.com>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Please don't blame me for bugs you introduced.

> - Arnaud

cu
Adrian

--

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"Only a promise," Lao Er said.
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