Re: [PATCH v3 0/3] Fix crashes and warning in ext4 unit test

[Kemeng Shi]

on 3/3/2024 11:33 PM, Guenter Roeck wrote:
> On 3/2/24 10:17, Kemeng Shi wrote:
>> v2->v3:
>> -fix warning that sb->s_umount is still held when unit test finishs
>> -fix warning that sbi->s_freeclusters_counter is used before
>> initialization.
>>
>> v1->v2:
>> -properly handle error from sget()
>>
>> Previously, the new mballoc unit tests are only tested by running
>> "./tools/testing/kunit/kunit.py run ..." in which case only rare configs
>> are enabled.
>> This series fixes issues when more debug configs are enabled. Fixes are
>> tested with and without kunit_tool [1].
>>
>> [1] https://docs.kernel.org/dev-tools/kunit/run_manual.html
>>
>> Kemeng Shi (3):
>>    ext4: alloc test super block from sget
>>    ext4: hold group lock in ext4 kunit test
>>    ext4: initialize sbi->s_freeclusters_counter before use in kunit test
>>
>>   fs/ext4/mballoc-test.c | 77 ++++++++++++++++++++++++++++++++----------
>>   1 file changed, 60 insertions(+), 17 deletions(-)
>>
> 
> I still see crashes with this version. Some examples below.
> 
Thanks so much for the test and report. It's likely cuased by using
sbi->s_dirtyclusters_counter uninitialized. Will fix it in next
version.

Kemeng
> Guenter
> 
> ---
> mips:
> 
>         KTAP version 1
>         # Subtest: test_mark_diskspace_used
> CPU 0 Unable to handle kernel paging request at virtual address 00780000, epc == 807a4b28, ra == 807a4c20
> Oops[#1]:
> CPU: 0 PID: 112 Comm: kunit_try_catch Tainted: G                 N 6.8.0-rc6-next-20240301-11397-g2cd922b7255b #1
> Hardware name: mti,malta
> $ 0   : 00000000 00000001 00780000 00000000
> $ 4   : 811c6de0 00000000 00000001 00000000
> $ 8   : 00000005 00000000 82f0cc00 00000001
> $12   : ffffffff 00000002 00000000 fff80000
> $16   : 82d99558 811c6de0 00000000 00000020
> $20   : 811c0000 00000000 00000001 00000000
> $24   : 00000000 80415884
> $28   : 82f1c000 82f1f9f8 00000000 807a4c20
> Hi    : 00000000
> Lo    : 00002128
> epc   : 807a4b28 percpu_counter_add_batch+0x7c/0x224
> ra    : 807a4c20 percpu_counter_add_batch+0x174/0x224
> Status: 1000a402    KERNEL EXL
> Cause : 00800008 (ExcCode 02)
> BadVA : 00780000
> PrId  : 00019300 (MIPS 24Kc)
> Modules linked in:
> Process kunit_try_catch (pid: 112, threadinfo=82f1c000, task=82c2cec0, tls=00000000)
> Stack : 82d99400 b332f3f3 00000000 b332f3f3 82f1fb20 811c0000 00000000 00000000
>         811c0000 82d99400 82d63800 00000008 00000000 80414ac4 00000000 801a4aa4
>         00000001 00000000 00000020 00000001 00000000 82f1fa70 00000000 00000023
>         00000080 82f1fb20 82f1fb20 00000380 82c2cec0 00000000 00000000 b332f3f3
>         82f1fae0 00000025 82d63800 821bbc08 00000001 00000001 821f12a8 82f0cc00
>         ...
> Call Trace:
> [<807a4b28>] percpu_counter_add_batch+0x7c/0x224
> [<80414ac4>] ext4_mb_mark_diskspace_used+0x25c/0x26c
> [<80414ba4>] test_mark_diskspace_used+0xd0/0x308
> [<806e8fe0>] kunit_try_run_case+0x70/0x204
> [<806eb1dc>] kunit_generic_run_threadfn_adapter+0x1c/0x28
> [<80162be0>] kthread+0x128/0x150
> [<80103038>] ret_from_kernel_thread+0x14/0x1c
> Code: 02242021  8c820000  00431021 <8c5e0000> 001e17c3  03d5a021  00523021  029e902b  02469021
> ---[ end trace 0000000000000000 ]---
> 
> Various arm emulations:
> [    6.617298]         # Subtest: test_mark_diskspace_used
> [    6.620243]         ok 1 block_bits=10 cluster_bits=3 blocks_per_group=8192 group_count=4 desc_size=64
> [    6.622190] 8<--- cut here ---
> [    6.622374] Unable to handle kernel paging request at virtual address 0a3f6000 when read
> [    6.622549] [0a3f6000] *pgd=00000000
> [    6.622960] Internal error: Oops: 5 [#1] SMP ARM
> [    6.623138] Modules linked in:
> [    6.623342] CPU: 0 PID: 187 Comm: kunit_try_catch Tainted: G                 N 6.8.0-rc6-next-20240301-11397-g2cd922b7255b #1
> [    6.623573] Hardware name: Freescale i.MX6 Ultralite (Device Tree)
> [    6.623738] PC is at percpu_counter_add_batch+0x2c/0x110
> [    6.624171] LR is at percpu_counter_add_batch+0xa8/0x110
> 
>