Re: [linux-cifs-client] Re: BUG: scheduling while atomic - linux 2.6.22

[Dave Kleikamp <shaggy@linux.vnet.ibm.com>]

On Tue, 2007-08-28 at 07:11 +0800, Michael Deegan wrote:
> Hi,
> 
> On Tue Aug 7 16:00:19 GMT 2007, Martin Koegler  wrote:
> > A vanilla 2.6.22 kernel (SMP PREEMPT i686) produced the following messages, while working with a CIFS mount point:
> > 
> > Aug  7 16:12:30 localhost kernel: BUG: scheduling while atomic: bash/0x00000001/5868
> > Aug  7 16:12:30 localhost kernel:  [schedule+1312/2250] schedule+0x520/0x8ca
> > Aug  7 16:12:30 localhost kernel:  [__switch_to+157/410] __switch_to+0x9d/0x19a
> > Aug  7 16:12:30 localhost kernel:  [kernel_sendmsg+39/53] kernel_sendmsg+0x27/0x35
> > Aug  7 16:12:30 localhost kernel:  [<e0c204aa>] wait_for_response+0xca/0x134 [cifs]
> > Aug  7 16:12:30 localhost kernel:  [autoremove_wake_function+0/53] autoremove_wake_function+0x0/0x35
> > Aug  7 16:12:30 localhost kernel:  [<e0c20a5c>] SendReceive+0x12b/0x457 [cifs]
> > Aug  7 16:12:30 localhost kernel:  [<e0c0abf4>] CIFSSMBOpen+0x109/0x2c2 [cifs]
> > Aug  7 16:12:30 localhost kernel:  [<e0c170d3>] cifs_reopen_file+0x123/0x3d0 [cifs]
> > Aug  7 16:12:30 localhost kernel:  [<e0c17cf4>] find_writable_file+0x7b/0xdb [cifs]
> > Aug  7 16:12:30 localhost kernel:  [<e0c183e8>] is_size_safe_to_change+0x18/0x7a [cifs]
> > Aug  7 16:12:30 localhost kernel:  [<e0c26959>] cifs_readdir+0x1118/0x167f [cifs]
> > Aug  7 16:12:30 localhost kernel:  [filldir64+0/197] filldir64+0x0/0xc5
> > Aug  7 16:12:30 localhost kernel:  [filldir64+0/197] filldir64+0x0/0xc5
> > Aug  7 16:12:30 localhost kernel:  [vfs_readdir+124/145] vfs_readdir+0x7c/0x91
> > Aug  7 16:12:30 localhost kernel:  [sys_getdents64+99/165] sys_getdents64+0x63/0xa5
> > Aug  7 16:12:30 localhost kernel:  [syscall_call+7/11] syscall_call+0x7/0xb
> > Aug  7 16:12:30 localhost kernel:  [netlbl_unlabel_list+143/479] netlbl_unlabel_list+0x8f/0x1df
> > Aug  7 16:12:30 localhost kernel:  =======================
> > Aug  7 16:13:03 localhost kernel:  CIFS VFS: Send error in Close = -9
> 
> FWIW, I saw something very similar:
> 
> Aug 27 22:33:08 wibble kernel: BUG: scheduling while atomic: bash/0x00000001/4077
> Aug 27 22:33:08 wibble kernel:
> Aug 27 22:33:08 wibble kernel: Call Trace:
> Aug 27 22:33:08 wibble kernel:  [<ffffffff805265df>] __sched_text_start+0x5f/0x79b
> Aug 27 22:33:08 wibble kernel:  [<ffffffff8049cb7a>] kernel_sendmsg+0x2c/0x3e
> Aug 27 22:33:08 wibble kernel:  [<ffffffff8032ba42>] wait_for_response+0xbe/0x155
> Aug 27 22:33:08 wibble kernel:  [<ffffffff802392bf>] autoremove_wake_function+0x0/0x2e
> Aug 27 22:33:08 wibble kernel:  [<ffffffff8032c0e1>] SendReceive+0x1fb/0x3f8
> Aug 27 22:33:08 wibble kernel:  [<ffffffff803192c2>] CIFSSMBOpen+0x1c6/0x27a
> Aug 27 22:33:08 wibble kernel:  [<ffffffff80323b8a>] cifs_reopen_file+0x1ea/0x356
> Aug 27 22:33:08 wibble kernel:  [<ffffffff8032455c>] find_writable_file+0x84/0xe7
> Aug 27 22:33:08 wibble kernel:  [<ffffffff80324b51>] is_size_safe_to_change+0x16/0x4e
> Aug 27 22:33:08 wibble kernel:  [<ffffffff8032fbc7>] fill_in_inode+0x270/0x4ec
> Aug 27 22:33:08 wibble kernel:  [<ffffffff80330c67>] cifs_readdir+0xe24/0x1071
> Aug 27 22:33:08 wibble kernel:  [<ffffffff802733c8>] filldir64+0x0/0xb8
> Aug 27 22:33:08 wibble kernel:  [<ffffffff80218c71>] do_page_fault+0x40b/0x74a
> Aug 27 22:33:08 wibble kernel:  [<ffffffff80527ffb>] __mutex_lock_slowpath+0x234/0x23f
> Aug 27 22:33:08 wibble kernel:  [<ffffffff802733c8>] filldir64+0x0/0xb8
> Aug 27 22:33:08 wibble kernel:  [<ffffffff80273594>] vfs_readdir+0x5d/0x92
> Aug 27 22:33:08 wibble kernel:  [<ffffffff8027363e>] sys_getdents64+0x75/0xba
> Aug 27 22:33:08 wibble kernel:  [<ffffffff8052948d>] error_exit+0x0/0x84
> Aug 27 22:33:08 wibble kernel:  [<ffffffff8020958e>] system_call+0x7e/0x83
> Aug 27 22:33:08 wibble kernel:
> 
> I'm using a 2.6.22.1 kernel (with SMP and PREEMPT, including BKL) on Debian
> etch AMD64, and Samba 3.0.24-6etch4.

This is a known problem that is fixed in 2.6.23-rc4.  cifs_readdir()
takes a spinlock and calls a blocking function.  The fix is here:
http://git.kernel.org/gitweb.cgi?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=a403a0a370946e7dbcda6464a3509089daee54bc

Steve,
Has this patch been submitted to the stable kernel?

Thanks,
Shaggy
-- 
David Kleikamp
IBM Linux Technology Center

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