Randy Dunlap wrote:
quoted text
> Randy Dunlap wrote:
>> Miller, Mike (OS Dev) wrote:
>>>> -----Original Message-----
>>>> From: Randy Dunlap [mailto:randy.dunlap@oracle.com]
>>>> Sent: Thursday, September 25, 2008 3:40 PM
>>>> To: scsi
>>>> Cc: Jens Axboe; Miller, Mike (OS Dev); James Bottomley; lkml; akpm
>>>> Subject: Re: in 2.6.23-rc3-git7 in do_cciss_intr
>>>>
>>>> On Thu, 25 Sep 2008 13:33:07 -0700 Randy Dunlap wrote:
>>>>
>>>>> Jens Axboe wrote:
>>>>>> On Thu, Sep 04 2008, Miller, Mike (OS Dev) wrote:
>>>>>>>>>>> 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:2
>>>>>>>> 06
>>>>>>>>>> OK ...that's confusing.  It seems to be saying that
>>>> ctrlr_info_t
>>>>>>>>>> * was NULL.  However, I can't see a way of getting into the
>>>>>>>> fifo_full
>>>>>>>>>> callback from do_cciss_intr ..
>>>>>>>>>> especially not with an NULL host.
>>>>>>>>>>
>>>>>>>>>> James
>>>>>>>>> That is weird. Even if we could get there fifo_full doesn't
>>>>>>>> do anything but wait for a bit.
>>>>>>>>
>>>>>>>> Hi,
>>>>>>>>
>>>>>>>> This just happened again.  This time it's on 2.6.27-rc5-git3.
>>>>>>>>
>>>>>>>> ~Randy
>>>>>>> Thanks Randy. I think. :)
>>>>>>>
>>>>>>> I'll try to recreate in my lab.
>>>>>> This looks somewhat strange, mostly like 'c' is NULL and it's
>>>>>> oopsing in in removeQ (I don't think Randy's analysis is
>>>> correct in
>>>>>> assuming it's 'h' and it's in fifo_full). Given that 'c'
>>>> cannot be
>>>>>> NULL, it's c->prev or c->next that are NULL.
>> This BUG: has happened (now) 5 times today.  Higher frequency than usual for
>> some reason.
>>
>> I enabled CCISS_DEBUG and added one printk in removeQ().  On the first call
> 
> s/first/second/
> 
> 
>> to removeQ(), both c->next and c->prev are NULL.
>>
>> Here's the kernel log output from cciss:

I added a printk() in addQ() as well.  Here's the new output:

HP CISS Driver (v 3.6.20)
ACPI: PCI Interrupt Link [LNKA] enabled at IRQ 54
cciss 0000:42:08.0: PCI INT A -> Link[LNKA] -> GSI 54 (level, high) -> IRQ 54
command = 147
irq = 36
board_id = 3211103c
cciss 0000:42:08.0: irq 87 for MSI/MSI-X
address 0 = fdf80000
cfg base address = 10
cfg base address index = 0
cfg offset = 400
Controller Configuration information
------------------------------------
   Signature = CISS
   Spec Number = 1
   Transport methods supported = 0x6
   Transport methods active = 0x3
   Requested transport Method = 0x0
   Coalesce Interrupt Delay = 0x0
   Coalesce Interrupt Count = 0x1
   Max outstanding commands = 0x256
   Bus Types = 0x200000
   Server Name =
   Heartbeat Counter = 0x1672


Trying to put board into Simple mode
I counter got to 1 0
Controller Configuration information
------------------------------------
   Signature = CISS
   Spec Number = 1
   Transport methods supported = 0x6
   Transport methods active = 0x3
   Requested transport Method = 0x0
   Coalesce Interrupt Delay = 0x0
   Coalesce Interrupt Count = 0x1
   Max outstanding commands = 0x256
   Bus Types = 0x200000
   Server Name =
   Heartbeat Counter = 0x1672


cciss0: <0x3238> at PCI 0000:42:08.0 IRQ 87 using DAC
cciss: intr_pending 8
cciss: addQ: Qptr=ffff88027e0100b8, c=ffff88007f83e000
cciss: removeQ: Qptr=ffff88027e0100b8, c=ffff88007f83e000, next=ffff88007f83e000, prev=ffff88007f83e000
Sending 7f83e000 - down to controller
cciss: addQ: Qptr=ffff88027e0100c0, c=ffff88007f83e000
cciss: intr_pending 8
cciss:  Read 4 back from board
cciss: removeQ: Qptr=ffff88027e0100c0, c=ffff88007f840000, next=0000000000000000, prev=0000000000000000
BUG: unable to handle kernel NULL pointer dereference at 0000000000000248
IP: [<ffffffffa0025106>] do_cciss_intr+0x706/0xb6c [cciss]
PGD 0
Oops: 0002 [#1] SMP
last sysfs file: /sys/block/ram15/dev
CPU 2
Modules linked in: cciss(+) ehci_hcd ohci_hcd uhci_hcd
Pid: 0, comm: swapper Not tainted 2.6.28-rc5 #1
RIP: 0010:[<ffffffffa0025106>]  [<ffffffffa0025106>] do_cciss_intr+0x706/0xb6c [cciss]
RSP: 0018:ffff88027f643ee8  EFLAGS: 00010087
RAX: 0000000000000000 RBX: ffff88007f840000 RCX: 000000000000a44f
RDX: 0000000000000000 RSI: 0000000000000046 RDI: ffffffff8080e634
RBP: ffff88027f643f18 R08: 0000000000000000 R09: ffff88017e964800
R10: 0000000000000000 R11: 0000000000000000 R12: ffff88027e000000
R13: 0000000000000000 R14: 0000000000000057 R15: 0000000000000086
FS:  00000000008558f0(0000) GS:ffff88017fc01c80(0000) knlGS:0000000000000000
CS:  0010 DS: 0018 ES: 0018 CR0: 000000008005003b
CR2: 0000000000000248 CR3: 0000000000201000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process swapper (pid: 0, threadinfo ffff88017fa9e000, task ffff88017fa5d400)
Stack:
 0000000000000030 ffff88027f627500 0000000000000000 0000000000000000
 0000000000000057 0000000000000000 ffff88027f643f48 ffffffff8026a8b9
 ffffffff8074ab00 0000000000000057 ffff88027f627500 ffffffff8074ab58
Call Trace:
 <IRQ> <0> [<ffffffff8026a8b9>] handle_IRQ_event+0x27/0x57
 [<ffffffff8026c424>] handle_edge_irq+0xde/0x11f
 [<ffffffff8020e29b>] do_IRQ+0xfc/0x175
 [<ffffffff8020c3e6>] ret_from_intr+0x0/0xa
 <EOI> <0> [<ffffffff8023c7d2>] ? ksoftirqd+0x0/0xa6
 [<ffffffff80212575>] ? default_idle+0x2b/0x40
 [<ffffffff80212799>] ? c1e_idle+0xe5/0xec
 [<ffffffff8056a7f6>] ? atomic_notifier_call_chain+0xf/0x11
 [<ffffffff8020acd1>] ? cpu_idle+0x40/0x5e
 [<ffffffff8056284e>] ? start_secondary+0x174/0x179
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
RIP  [<ffffffffa0025106>] do_cciss_intr+0x706/0xb6c [cciss]
 RSP <ffff88027f643ee8>
CR2: 0000000000000248
Kernel panic - not syncing: Fatal exception in interrupt

~Randy

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