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

From: Jiri Slaby
Date: Sat Mar 18 2006 - 20:03:09 EST


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Jiri Slaby napsal(a):
> 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 :(.
Yup, I've got it:
while /bin/true; do cd /home/ftp/misc/.ftpaccess; done
[nonexistent dir]
kill it
and

Mar 19 02:03:08 localhost automount[25680]: failed to mount
/home/ftp/misc/.ftpaccess
Mar 19 02:03:08 localhost automount[25682]: failed to mount
/home/ftp/misc/.ftpaccess
Mar 19 02:03:08 localhost kernel: BUG: atomic counter underflow at:
Mar 19 02:03:08 localhost kernel: [<c0104736>] show_trace+0x13/0x15
Mar 19 02:03:08 localhost kernel: [<c0104873>] dump_stack+0x1e/0x20
Mar 19 02:03:08 localhost kernel: [<c01d6c97>] autofs4_wait+0x751/0x93a
Mar 19 02:03:08 localhost kernel: [<c01d543b>] try_to_fill_dentry+0xca/0x11c
Mar 19 02:03:08 localhost kernel: [<c01d59b3>] autofs4_revalidate+0xe1/0x148
Mar 19 02:03:08 localhost kernel: [<c0171338>] do_lookup+0x40/0x157
Mar 19 02:03:08 localhost kernel: [<c0172ec4>] __link_path_walk+0x804/0xe8c
Mar 19 02:03:08 localhost kernel: [<c017359c>] link_path_walk+0x50/0xe8
Mar 19 02:03:08 localhost kernel: [<c01738b7>] do_path_lookup+0x10f/0x26d
Mar 19 02:03:08 localhost kernel: [<c017429c>] __user_walk_fd+0x33/0x50
Mar 19 02:03:08 localhost kernel: [<c0174412>] __user_walk+0x17/0x19
Mar 19 02:03:08 localhost automount[25683]: failed to mount
/home/ftp/misc/.ftpaccess
Mar 19 02:03:08 localhost kernel: [<c0162fb3>] sys_chdir+0x1a/0x77
Mar 19 02:03:08 localhost kernel: [<c0103127>] syscall_call+0x7/0xb
Mar 19 02:03:08 localhost automount[25684]: failed to mount
/home/ftp/misc/.ftpaccess

Now, I am going to test, if this dissapeared after your patch.

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