Re: in 2.6.23-rc3-git7 in do_cciss_intr

[Randy Dunlap <randy.dunlap@oracle.com>]

James Bottomley wrote:
> On Fri, 2008-08-22 at 15:48 +0000, Miller, Mike (OS Dev) wrote:
>>> -----Original Message-----
>>> From: Randy Dunlap [mailto:randy.dunlap@oracle.com]
>>> Sent: Thursday, August 21, 2008 7:27 PM
>>> To: Miller, Mike (OS Dev)
>>> Cc: lkml; scsi; akpm
>>> Subject: Re: in 2.6.23-rc3-git7 in do_cciss_intr
>>>
>>> On Thu, 21 Aug 2008 16:25:24 +0000 Miller, Mike (OS Dev) wrote:
>>>
>>>>>> Randy,
>>>>>> We know of a race condition in cciss_init_one. It's fixed
>>>>> in 2.6.26 I believe. Here's the patch:
>>>>>>
>>> http://groups.google.com/group/linux.kernel/browse_thread/thread/7b3
>>>>> 9f
>>> 2b77622ab03/4f5f45c008655ca1?hl=en&lnk=gst&q=cciss#4f5f45c008655ca
>>>>>> 1
>>>>>
>>>>> Mike,
>>>>> Sorry, but my fingers have typoed the $subject.  My bad.
>>>>> Kernel is 2.6.27-rc3-git7 (from above):
>>>>>
>>>>>>>>> Modules linked in: cciss(+) ehci_hcd ohci_hcd uhci_hcd
>>>>>>>>> Pid: 0, comm: swapper Not tainted 2.6.27-rc3-git7 #1
>>>>>>>>> RIP: 0010:[<ffffffffa001bb68>]  [<ffffffffa001bb68>]
>>>>>>>>> do_cciss_intr+0x627/0xa6c [cciss]
>>>> Hmmmmm, let me know what happens from your retest. I'll
>>> look at this
>>>> as soon as I finish what I'm doing now. We trying to spin
>>> for our test
>>>> teams but I have something hopelessly broken. :(
>>> It didn't BUG in the retest.  That just means that it's more
>>> difficult to find/fix, right?
>> Yup.
> 
> Randy,
> 
> If you can't reproduce it, could you use the debug information or gdb to
> tell us what line in the source code this:
> 
> do_cciss_intr+0x627
> 
> corresponds to?  That might help isolating the problem.


Sure, here's an attempt at that.  Please let me know if you want it
differently or some other info.


(gdb) x/20i do_cciss_intr+0x627
0x3b68 <do_cciss_intr+1575>:    mov    %rdx,0x248(%rax)
0x3b6f <do_cciss_intr+1582>:    mov    0x248(%rbx),%rdx
0x3b76 <do_cciss_intr+1589>:    mov    %rax,0x240(%rdx)
0x3b7d <do_cciss_intr+1596>:    jmp    0x3b8b <do_cciss_intr+1610>
0x3b7f <do_cciss_intr+1598>:    movq   $0x0,0x100c0(%r12)
0x3b8b <do_cciss_intr+1610>:    mov    0x234(%rbx),%eax
0x3b91 <do_cciss_intr+1616>:    test   %eax,%eax
0x3b93 <do_cciss_intr+1618>:    jne    0x3f27 <do_cciss_intr+2534>
0x3b99 <do_cciss_intr+1624>:    mov    0x250(%rbx),%r14
0x3ba0 <do_cciss_intr+1631>:    movl   $0x0,0xcc(%r14)
0x3bab <do_cciss_intr+1642>:    mov    0x228(%rbx),%r8
0x3bb2 <do_cciss_intr+1649>:    mov    0x2(%r8),%dx
0x3bb7 <do_cciss_intr+1654>:    test   %dx,%dx
0x3bba <do_cciss_intr+1657>:    je     0x3f0e <do_cciss_intr+2509>


$ addr2line -e cciss.o -f  do_cciss_intr+0x627
SA5_fifo_full
/home/rdunlap/linsrc/linux-2.6.27-rc3-git7/drivers/block/cciss.h:206



$ ../../scripts/decodecode  < cciss.code 
Code: 8b 83 48 02 00 00 48 39 d8 74 37 49 39 9c 24 c0 00 01 00 75 08 49 89 84 24 c0 00 01 00 48 8b 83 40 02 00 00 48 8b 93 48 02 00 00 <48> 89 90 48 02 00 00 48 8b 93 48 02 00 00 48 89 82 40 02 00 00

/tmp/tmp.HbrjP23089.o:     file format elf64-x86-64

Disassembly of section .text:

0000000000000000 <.text>:
   0:   8b 83 48 02 00 00       mov    0x248(%rbx),%eax
   6:   48 39 d8                cmp    %rbx,%rax
   9:   74 37                   je     0x42
   b:   49 39 9c 24 c0 00 01    cmp    %rbx,0x100c0(%r12)
  12:   00 
  13:   75 08                   jne    0x1d
  15:   49 89 84 24 c0 00 01    mov    %rax,0x100c0(%r12)
  1c:   00 
  1d:   48 8b 83 40 02 00 00    mov    0x240(%rbx),%rax
  24:   48 8b 93 48 02 00 00    mov    0x248(%rbx),%rdx

/tmp/tmp.HbrjP23089.o:     file format elf64-x86-64

Disassembly of section .text:

0000000000000000 <.text>:
   0:   48 89 90 48 02 00 00    mov    %rdx,0x248(%rax)
   7:   48 8b 93 48 02 00 00    mov    0x248(%rbx),%rdx
   e:   48 89 82 40 02 00 00    mov    %rax,0x240(%rdx)


~Randy