Re: BUG: atomic counter underflow [Was: 2.6.16-rc6-mm1]

From: Jiri Slaby
Date: Fri Mar 17 2006 - 12:45:02 EST


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Ian Kent napsal(a):
> On Sun, 12 Mar 2006, Jiri Slaby wrote:
>
>> Andrew Morton wrote:
>>> ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.16-rc6/2.6.16-rc6-mm1/
>> [snip]
>>> +remove-redundant-check-from-autofs4_put_super.patch
>>> +autofs4-follow_link-missing-funtionality.patch
>>>
>>> Update autofs4 patches in -mm.
>> Hello,
>>
>> I caught this during ftp browsing autofs-bind-mounted directories. I don't know
>> circumstancies and if the patches above are source of problem. I also don't know
>> if -rc6-mm1 is the first one.
>
> btw what do you mean autofs-bind-mounted ?
Hmm, I am unable to reproduce it :(.
I have ftp dir, there is misc directory which is autofs maintained and --bind
mounted directories from some corners of / (i. e. ntfs and ext3 dirs mounted
through --bind).
in /etc/auto.master:
...
/home/ftp/misc /etc/auto.ftpmisc
...

in /etc/auto.ftpmisc:
...
l -fstype=bind :/l/latest
...

Somebody was browsing through the ftp binded tree and these bugs appeared (only
twice).
>
>> BUG: atomic counter underflow at:
>> [<c0104736>] show_trace+0x13/0x15
>> [<c0104873>] dump_stack+0x1e/0x20
>> [<c01d6c97>] autofs4_wait+0x751/0x93a
>> [<c01d543b>] try_to_fill_dentry+0xca/0x11c
>> [<c01d59b3>] autofs4_revalidate+0xe1/0x148
>> [<c0171338>] do_lookup+0x40/0x157
>> [<c0172ec4>] __link_path_walk+0x804/0xe8c
>> [<c017359c>] link_path_walk+0x50/0xe8
>> [<c01738b7>] do_path_lookup+0x10f/0x26d
>> [<c017429c>] __user_walk_fd+0x33/0x50
>> [<c016d226>] vfs_stat_fd+0x1e/0x50
>> [<c016d30d>] vfs_stat+0x20/0x22
>> [<c016d328>] sys_stat64+0x19/0x2d
>> [<c0103127>] syscall_call+0x7/0xb
>>
>
> There's some suspicious code in waitq.c.
> Could you try the following patch for me please?

I can't confirm... I don't know.

regards,
- --
Jiri Slaby www.fi.muni.cz/~xslaby
\_.-^-._ jirislaby@xxxxxxxxx _.-^-._/
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