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Subject: Re: bioset changes in 4.18 broke aha1542
To:     Ondrej Zary <linux@rainbow-software.org>
Cc:     Kent Overstreet <kent.overstreet@gmail.com>,
        linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org
References: <201810182034.51724.linux@rainbow-software.org>
 <201810182222.41789.linux@rainbow-software.org>
 <2baee56c-8e56-3dba-0000-1af1392a89f7@kernel.dk>
 <201810182258.49710.linux@rainbow-software.org>
From:   Jens Axboe <axboe@kernel.dk>
Message-ID: <e5518cfa-6111-c167-1b29-27e9166041df@kernel.dk>
Date:   Thu, 18 Oct 2018 15:04:30 -0600
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On 10/18/18 2:58 PM, Ondrej Zary wrote:
> On Thursday 18 October 2018 22:28:35 Jens Axboe wrote:
>> On 10/18/18 2:22 PM, Ondrej Zary wrote:
>>> On Thursday 18 October 2018 22:10:31 Jens Axboe wrote:
>>>> On 10/18/18 2:04 PM, Ondrej Zary wrote:
>>>>> On Thursday 18 October 2018 21:59:09 Jens Axboe wrote:
>>>>>> On 10/18/18 1:55 PM, Ondrej Zary wrote:
>>>>>>> On Thursday 18 October 2018 20:58:57 Jens Axboe wrote:
>>>>>>>> On 10/18/18 12:34 PM, Ondrej Zary wrote:
>>>>>>>>> Hello,
>>>>>>>>> aha1542 works fine in 4.17 but crashes in 4.18. It's hard to bisect because
>>>>>>>>> of many commits that don't compile.
>>>>>>>>> # only skipped commits left to test
>>>>>>>>> # possible first bad commit: [52190f8abe7f2bf2b4e5f9760cbcc1427ca2136b] fs: convert block_dev.c to bioset_init()
>>>>>>>>> # possible first bad commit: [a47a28b74a5c7c27bf621276b85ad6c124651236] target: convert to bioset_init()/mempool_init()
>>>>>>>>> # possible first bad commit: [6f1c819c219f7841079f0f43ab62727a55b0d849] dm: convert to bioset_init()/mempool_init()
>>>>>>>>> # possible first bad commit: [afeee514ce7f4cab605beedd03be71ebaf0c5fc8] md: convert to bioset_init()/mempool_init()
>>>>>>>>> # possible first bad commit: [d19936a26658a7a53edd5619d631ee2c2c3151a2] bcache: convert to bioset_init()/mempool_init()
>>>>>>>>> # possible first bad commit: [b906bbb6997785d9ea0bd3f5585537afa6257c43] lightnvm: convert to bioset_init()/mempool_init()
>>>>>>>>>
>>>>>>>>> Testing manually, a47a28b74a5c7c27bf621276b85ad6c124651236 works.
>>>>>>>>> 52190f8abe7f2bf2b4e5f9760cbcc1427ca2136b does not compile
>>>>>>>>> 8ac9f7c1fd1d342e82ddf078425423b050652ba0 does not compile
>>>>>>>>> e292d7bc63c8f2adb3dfda27910e805f1b6557f9 does not compile
>>>>>>>>> dad08527525f9a8ac9c7f278864c65f94bc5e9b3 does not compile
>>>>>>>>> 943cf9f3ca16133dbd00f9a4cbfea46512fcb0e8 works
>>>>>>>>> ..
>>>>>>>>> fedc3abe7bd2dcc4c80bcf3cff8708a3908d8219 works
>>>>>>>>> 04c4950d5b373ba712d928592e05e73510785bca crashes
>>>>>>>>
>>>>>>>> It looks like the ISA bioset pool isn't being initialized. You should
>>>>>>>> have messages like this in your dmesg:
>>>>>>>>
>>>>>>>> isa pool size: 16 pages
>>>>>>>>
>>>>>>>> (which you do), but also something on the bioset section. Do you have
>>>>>>>> this one:
>>>>>>>>
>>>>>>>> pool size: 64 pages
>>>>>>>>
>>>>>>>> as well?
>>>>>>>>
>>>>>>>
>>>>>>> No, it's not there.
>>>>>>
>>>>>> Can you attach your .config? I'm guessing CONFIG_HIGHMEM* isn't set.
>>>>>>
>>>>>
>>>>> It is.
>>>>
>>>> Puzzled... Does this work?
>>>>
>>>>
>>>> diff --git a/block/bounce.c b/block/bounce.c
>>>> index b30071ac4ec6..49564a1bfd22 100644
>>>> --- a/block/bounce.c
>>>> +++ b/block/bounce.c
>>>> @@ -35,10 +35,6 @@ static mempool_t page_pool, isa_page_pool;
>>>>  static __init int init_emergency_pool(void)
>>>>  {
>>>>  	int ret;
>>>> -#if defined(CONFIG_HIGHMEM) && !defined(CONFIG_MEMORY_HOTPLUG)
>>>> -	if (max_pfn <= max_low_pfn)
>>>> -		return 0;
>>>> -#endif
>>>>  
>>>>  	ret = mempool_init_page_pool(&page_pool, POOL_SIZE, 0);
>>>>  	BUG_ON(ret);
>>>>
>>>
>>> Yes, it does! 
>>> bounce: pool size: 64 pages
>>> and aha1542 works.
>>>
>>> Also added printks for pfn:
>>> max_pfn=65520, max_low_pfn=65520
>>
>> This should be a better fix, though I'm still puzzled why we need
>> it now. Can you test this one?
>>
>>
>> diff --git a/block/bounce.c b/block/bounce.c
>> index b30071ac4ec6..1356a2f4aae2 100644
>> --- a/block/bounce.c
>> +++ b/block/bounce.c
>> @@ -31,6 +31,24 @@
>>  static struct bio_set bounce_bio_set, bounce_bio_split;
>>  static mempool_t page_pool, isa_page_pool;
>>  
>> +static __init void init_bounce_bioset(void)
>> +{
>> +	static bool bounce_bs_setup;
>> +	int ret;
>> +
>> +	if (bounce_bs_setup)
>> +		return;
>> +
>> +	ret = bioset_init(&bounce_bio_set, BIO_POOL_SIZE, 0, BIOSET_NEED_BVECS);
>> +	BUG_ON(ret);
>> +	if (bioset_integrity_create(&bounce_bio_set, BIO_POOL_SIZE))
>> +		BUG_ON(1);
>> +
>> +	ret = bioset_init(&bounce_bio_split, BIO_POOL_SIZE, 0, 0);
>> +	BUG_ON(ret);
>> +	bounce_bs_setup = true;
>> +}
>> +
>>  #if defined(CONFIG_HIGHMEM)
>>  static __init int init_emergency_pool(void)
>>  {
>> @@ -44,14 +62,7 @@ static __init int init_emergency_pool(void)
>>  	BUG_ON(ret);
>>  	pr_info("pool size: %d pages\n", POOL_SIZE);
>>  
>> -	ret = bioset_init(&bounce_bio_set, BIO_POOL_SIZE, 0, BIOSET_NEED_BVECS);
>> -	BUG_ON(ret);
>> -	if (bioset_integrity_create(&bounce_bio_set, BIO_POOL_SIZE))
>> -		BUG_ON(1);
>> -
>> -	ret = bioset_init(&bounce_bio_split, BIO_POOL_SIZE, 0, 0);
>> -	BUG_ON(ret);
>> -
>> +	init_bounce_bioset();
>>  	return 0;
>>  }
>>  
>> @@ -102,6 +113,7 @@ int init_emergency_isa_pool(void)
>>  	BUG_ON(ret);
>>  
>>  	pr_info("isa pool size: %d pages\n", ISA_POOL_SIZE);
>> +	init_bounce_bioset();
>>  	return 0;
>>  }
>>  
>>
> 
> WARNING: vmlinux.o(.text+0x1a5ad7): Section mismatch in reference from the function init_emergency_isa_pool() to the function .init.text:init_bounce_bioset()
> The function init_emergency_isa_pool() references
> the function __init init_bounce_bioset().
> This is often because init_emergency_isa_pool lacks a __init
> annotation or the annotation of init_bounce_bioset is wrong.
> 
> And it does not work:
> [  122.395558] scsi host2: Adaptec AHA-1542 (SCSI-ID 7) at IO 0x330, IRQ 11, DMA 7
> [  122.471853] scsi host2: Adaptec 1542
> [  122.484207] bounce: isa pool size: 16 pages
> [  122.488722] BUG: unable to handle kernel NULL pointer dereference at 00000fff
> [  122.492501] *pde = 00000000
> [  122.492501] Oops: 0000 [#1] SMP
> [  122.492501] CPU: 0 PID: 51 Comm: kworker/u2:1 Not tainted 4.19.0-rc7+ #296
> [  122.492501] Hardware name:  /i440ZX-W977TF, BIOS 4.51 PG 07/12/00
> [  122.492501] Workqueue: events_unbound async_run_entry_fn
> [  122.492501] EIP: init_bounce_bioset+0x2/0x63
> 
> Removing __init from init_bounce_bioset() makes it work.

Thanks, I missed that the isa part wasn't __init.

-- 
Jens Axboe