smbd blocks for 120 secs and then hangs in D state

[Vijai Baskar]

The server and the client are different.. Server is the board and
client is my PC.

vijai

On Mon, Aug 23, 2010 at 4:47 PM, Jeff Layton <jlayton at redhat.com> wrote:
> On Mon, 23 Aug 2010 10:40:34 +0530
> Vijai Baskar <cristalmaze at gmail.com> wrote:
>
>> Hi all,
>>
>> I am running a samba copy of a 4GB file from my local hard disk to a
>> remote hard disk and then find md5sum of the same file in the remote
>> hard disk through samba read. I do the following to accomplish this:
>>
>> 1. mount -t cifs //ip-addr/data /mnt
>> 2. cp /home/4g /mnt
>> 3. md5sum /mnt/4g
>>
>> After a few iterations of the above operation I get the following
>> warning on the board:
>>
>> echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
>> [ 6122.450000] smbd          D c0204908     0  9712    372 0x00000000
>> [ 6122.480000] [<c0204908>] (schedule+0x2dc/0x328) from [<c0204980>]
>> (io_schedule+0x2c/0x48)
>> [ 6122.500000] [<c0204980>] (io_schedule+0x2c/0x48) from [<c0072064>]
>> (sync_page+0x44/0x50)
>> [ 6122.530000] [<c0072064>] (sync_page+0x44/0x50) from [<c0204dd4>]
>> (__wait_on_bit_lock+0x5c/0xa8)
>> [ 6122.560000] [<c0204dd4>] (__wait_on_bit_lock+0x5c/0xa8) from
>> [<c0071ff0>] (__lock_page+0x88/0xa0)
>> [ 6122.590000] [<c0071ff0>] (__lock_page+0x88/0xa0) from [<c007b530>]
>> (truncate_inode_pages_range+0x2e4/0x38c)
>> [ 6122.620000] [<c007b530>] (truncate_inode_pages_range+0x2e4/0x38c)
>> from [<c007b5f0>] (truncate_inode_pages+0x18/0x20)
>> [ 6122.640000] [<c007b5f0>] (truncate_inode_pages+0x18/0x20) from
>> [<c0085acc>] (vmtruncate+0xe4/0x14c)
>> [ 6122.670000] [<c0085acc>] (vmtruncate+0xe4/0x14c) from [<c00a43a8>]
>> (inode_setattr+0x48/0x148)
>> [ 6122.700000] [<c00a43a8>] (inode_setattr+0x48/0x148) from
>> [<c00a4630>] (notify_change+0x188/0x1dc)
>> [ 6122.730000] [<c00a4630>] (notify_change+0x188/0x1dc) from
>> [<c0091440>] (do_truncate+0x6c/0x88)
>> [ 6122.760000] [<c0091440>] (do_truncate+0x6c/0x88) from [<c00915c0>]
>> (do_sys_ftruncate+0x164/0x170)
>> [ 6122.800000] [<c00915c0>] (do_sys_ftruncate+0x164/0x170) from
>> [<c00915e0>] (sys_ftruncate64+0x14/0x1c)
>> [ 6122.830000] [<c00915e0>] (sys_ftruncate64+0x14/0x1c) from
>> [<c0027fa0>] (ret_fast_syscall+0x0/0x2c)
>>
>> After this samba daemon hangs in the D state. I changed the values of
>> /proc/sys/vm/dirty_writeback_centisecs to 250 (default 500) and
>> /proc/sys/vm/dirty_expire_centisecs to 1000 (default 3000). But this
>> only delays the problem. ps-ax shows smbd in D state. This problem
>> seems to occur only during samba read.
>>
>> Can someone please provide me a solution for the above problem?
>>
>> regards,
>> vijai
>>
>
> (cc'ing linux-fsdevel and samba-technical as this problem is probably
> better reported there)
>
> The stack trace above is for smbd, so I doubt this has much to do with
> cifs per-se. Just to make sure though -- are the server and client the
> same host? Hint: if so, that configuration is prone to deadlock under
> heavy I/O.
>
> When reporting kernel bugs, it's also a good idea to mention the kernel
> version. It might also be helpful to know what the underlying
> filesystem is that's being served out.
>
> It looks like the process is hung trying to lock a page. Most likely
> that means that something else is holding that lock and not releasing
> it for some reason. Debugging this will probably mean figuring out
> what's holding that lock and why it's not releasing it.
>
> --
> Jeff Layton <jlayton at redhat.com>
>



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