Re: 2.6.16-rc6-mm1: BUG at fs/sysfs/inode.c:180

[Laurent Riffard <laurent.riffard@free.fr>]

Le 13.03.2006 15:00, Maneesh Soni a écrit :
> On Sun, Mar 12, 2006 at 03:01:58PM -0800, Andrew Morton wrote:
>>Laurent Riffard <laurent.riffard@free.fr> wrote:
>>>Le 12.03.2006 12:10, Andrew Morton a écrit :
>>> > ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.16-rc6/2.6.16-rc6-mm1/
>>>
>>> Hello,
>>>
>>> This kernel hangs on boot while trying to activate logical 
>>> volumes from initrd: 
>>>
>>> ------------[ cut here ]------------
>>> kernel BUG at fs/sysfs/inode.c:180!
>>> invalid opcode: 0000 [#1]
>>> last sysfs file: /block/ram0/dev
>>> Modules linked in: dm_mirror dm_mod
>>> CPU:    0
>>> EIP:    0060:[<c0172e71>]    Not tainted VLI
>>> EFLAGS: 00010246   (2.6.16-rc6-mm1 #123) 
>>> EIP is at sysfs_get_name+0xd/0x46
>>> eax: c15a49c8   ebx: dfe2b988   ecx: dff254d8   edx: c15a49cc
>>> esi: dfe87b05   edi: dfe2b988   ebp: dfe67d28   esp: dfe67d28
>>> ds: 007b   es: 007b   ss: 0068
>>> Process vgchange (pid: 242, threadinfo=dfe67000 task=dfe175d0)
>>> Stack: <0>dfe67d44 c01738c3 dffdc4b4 c15a49c8 dfe2b988 ffffffef dfe2b98d dfe67d60 
>>>        c0173dcd dff2a804 dfe2b984 dfe2b984 00000001 fffffffe dfe67d74 c0173f3b 
>>>        dfe67d6c c15a84d4 dfe2b984 dfe67d90 c01a33fd c03242d0 00000004 dfe2b8f8 
>>> Call Trace:
>>>  [<c0103a31>] show_stack_log_lvl+0x8b/0x95
>>>  [<c0103b69>] show_registers+0x12e/0x194
>>>  [<c0103e62>] die+0x14e/0x1db
>>>  [<c01040ba>] do_trap+0x7c/0x96
>>>  [<c0104319>] do_invalid_op+0x89/0x93
>>>  [<c01034db>] error_code+0x4f/0x54
>>>  [<c01738c3>] sysfs_dirent_exist+0x1c/0x65
>>>  [<c0173dcd>] create_dir+0x55/0x17d
>>>  [<c0173f3b>] sysfs_create_dir+0x46/0x61
>>>  [<c01a33fd>] kobject_add+0xa4/0x14c
>>>  [<c017267e>] register_disk+0x4b/0xe9
>>>  [<c019c28c>] add_disk+0x2e/0x3d
>>>  [<e08198a5>] create_aux+0x27e/0x2d7 [dm_mod]
>>>  [<e081991d>] dm_create+0xe/0x10 [dm_mod]
>>>  [<e081c317>] dev_create+0x4a/0x239 [dm_mod]
>>>  [<e081c18c>] ctl_ioctl+0x203/0x238 [dm_mod]
>>>  [<c0156648>] do_ioctl+0x3c/0x4f
>>>  [<c0156851>] vfs_ioctl+0x1f6/0x20d
>>>  [<c0156892>] sys_ioctl+0x2a/0x44
>>>  [<c01029bb>] sysenter_past_esp+0x54/0x75
>>> Code: 0b 30 01 72 85 28 c0 ff 06 31 db eb 07 89 f8 e8 d1 8d fe ff 83 c4 10 89 d8 5b 5e 5f c9 c3 55 85 c0 89 e5 74 06 83 78 14 00 75 08 <0f> 0b b4 00 73 d3 28 c0 8b 50 18 83 fa 08 74 22 7f 0a 83 fa 02 
>>
>>Thanks.
>>
>>Greg, can you please interpret this?  What does this BUG:
>>
>>const unsigned char * sysfs_get_name(struct sysfs_dirent *sd)
>>{
>>	struct attribute * attr;
>>	struct bin_attribute * bin_attr;
>>	struct relay_attribute * rel_attr;
>>	struct sysfs_symlink  * sl;
>>
>>	if (!sd || !sd->s_element)
>>		BUG();
>>
>>tell us?
>>
> 
> 
> I think here we have sd->s_element as NULL. This is probably due to
> my mistake in 
> 
> gregkh-driver-sysfs-fix-problem-with-duplicate-sysfs-directories-and-files.patch
> 
> NULL s_element which is used as cursor element is added to the s_children 
> list in sysfs_dir_open() and is removed in sysfs_dir_close(). So if in
> between s_children is parsed, one can see sysfs_dirent with NULL s_element.
> 
> Please try the following patch on top of -mm1
> 
> 
> Thanks
> Maneesh
> 
> 
> 
> 
> o sysfs_dirent_exist() should ignore sysfs_dirent with NULL s_element
>   as such element could have been added internally as cursor due to
>   ->open() on parent directory.
> 
> Signed-off-by: Maneesh Soni <maneesh@in.ibm.com>
> ---
> 
>  linux-2.6.16-rc6-mm1-maneesh/fs/sysfs/dir.c |   12 +++++++-----
>  1 files changed, 7 insertions(+), 5 deletions(-)
> 
> diff -puN fs/sysfs/dir.c~fix-sysfs-check-existing-sysfs_dirent fs/sysfs/dir.c
> --- linux-2.6.16-rc6-mm1/fs/sysfs/dir.c~fix-sysfs-check-existing-sysfs_dirent	2006-03-13 14:48:34.000000000 +0530
> +++ linux-2.6.16-rc6-mm1-maneesh/fs/sysfs/dir.c	2006-03-13 15:01:32.934811856 +0530
> @@ -63,11 +63,13 @@ int sysfs_dirent_exist(struct sysfs_dire
>  	struct sysfs_dirent * sd;
>  
>  	list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
> -		const unsigned char * existing = sysfs_get_name(sd);
> -		if (strcmp(existing, new))
> -			continue;
> -		else
> -			return -EEXIST;
> +		if (sd->s_element) {
> +			const unsigned char * existing = sysfs_get_name(sd);
> +			if (strcmp(existing, new))
> +				continue;
> +			else
> +				return -EEXIST;
> +		}
>  	}
>  
>  	return 0;
> _
> 

Ok, with this one, it works fine. 

Thanks.
-- 
laurent