> On 20 Nov 2024, at 07:21, Andrew Hewus Fresh <[email protected]> wrote:
>
> On Mon, Nov 18, 2024 at 06:26:30PM -0800, Andrew Hewus Fresh wrote:
>> On Tue, Nov 19, 2024 at 11:59:50AM +1000, David Gwynne wrote:
>>> On Mon, Nov 18, 2024 at 03:26:21PM -0800, Andrew Hewus Fresh wrote:
>>>> On Sun, Nov 17, 2024 at 04:16:17PM +1000, David Gwynne wrote:
>>>>> On Sat, Nov 16, 2024 at 07:36:37PM -0800, Andrew Hewus Fresh wrote:
>>>>>> I finally got around to fixing my alpha, which involved replacing the
>>>>>> disk. That meant I have to scp some stuff over to to it and after a bit
>>>>>> of time it panics:
>>>>>>
>>>>>> panic: mtx 0xfffffe000002a628: locking against myself
>>>>>> Stopped at db_enter+0x8: lda sp,10(sp)
>>>>>> TID PID UID PRFLAGS PFLAGS CPU COMMAND
>>>>>> *204699 79774 0 0x14000 0x200 0 softnet0
>>>>>> db_enter(0, 7ffffe00e0003f8, 1, 8, 3, 8) at db_enter+0x8
>>>>>> panic(?, fffffe000002a628, 1b0, 10, a, 1) at panic+0xe8
>>>>>> mtx_enter(?, ?, 1b0, 10, a, 1) at mtx_enter+0xb4
>>>>>> ifq_set_oactive(?, ?, 1b0, 10, a, 1) at ifq_set_oactive+0x50
>>>>>
>>>>> this is from src/sys/net/ifq.c r1.50 where i added a counter for the
>>>>> number of times oactive gets set. because there's checks and multiple
>>>>> things being tweaked i used the ifq mutex to serialise the updates.
>>>>>
>>>>> de(4) uses ifq_deq_begin to try and shove an mbuf onto the hardware,
>>>>> which takes but doesnt release the ifq mutex until ifq_deq_commit or
>>>>> ifq_deq_rollback is called. so while it's holding the mutex is calls
>>>>> ifq_set_oactive, which also tries to take the mutex.
>>>>>
>>>>> i honestly don't understand what de(4) is doing with the hardware and
>>>>> packet setup, so i dont feel confident changing the driver to avoid
>>>>> this. the least worst alternative i could think of is to provide an
>>>>> alternative set_oactive it can call.
>>>>>
>>>>> the diff below should fix this.
>>>>
>>>> I mean, it "fixed" the locking against myself error :-)
>>>
>>> nice work getting a kernel build going.
>>
>> Thanks, handily I have serial console and the install kernel lets me
>> `ftp` things onto the disk.
>>
>>
>>>> de0 at pci0 dev 11 function 0 "DEC 21040" rev 0x23, DEC 21040 pass 2.3:
>>>> isa irq 5, address ...
>>>> panic: mutex 0xfffffe000002a628 not held in ifq_deq_set_oactive
>>>> Stopped at db_enter+0x8: lda sp,10(sp)
>>>> TID PID UID PRFLAGS PFLAGS CPU COMMAND
>>>> * 0 0 0 0x10000 0x200 0 swapper
>>>> db_enter(0, 7ffffe00e0003f8, 1, 8, 3, fffffc0000000008) at db_enter+0x8
>>>> panic(?, fffffe000002a628, fffffc0000bc9718, 1, 5, 1) at panic+0xe8
>>>> ifq_deq_set_oactive(?, ?, fffffc0000bc9718, 1, 5, 1) at
>>>> ifq_deq_set_oactive+0x8
>>>> 8
>>>> tulip_txput(?, ?, fffffe000002a000, ?, 5, 1) at tulip_txput+0x5e8
>>>
>>> hrm.
>>>
>>> this might be better. or it might not even compile.
>>
>> We'll find out eventually. Thank you!
>
> Good news! The second patch seems to be working much better. I got it
> compiled, it booted up, I copied a bunch of files over ssh and no panics
> so far!
alright, i'll commit it.
