Re: LTP: fork13: kernel panic on rk3399-rock-pi-4 running mainline 6.10.rc3

[David Hildenbrand <david@redhat.com>]

On 11.06.24 13:39, Baolin Wang wrote:
> 
> 
> On 2024/6/11 18:32, David Hildenbrand wrote:
>> On 11.06.24 12:14, Naresh Kamboju wrote:
>>> The kernel panic was noticed while running LTP syscalls fork13 (long
>>> running) on
>>> the mainline master 6.10.rc3 kernel on arm64 rk3399-rock-pi-4 device.
>>>
>>> Please find detailed logs in the links,
>>>
>>> As you know fork13 is a stress test case trying to generate a maximum
>>> number
>>> of PID's in a 100,000 loop.
>>>
>>> This device is running via NFS mounted filesystem.
>>>
>>> I have tried to reproduce this problem in a loop but failed to
>>> reproduce the
>>> crash.
>>>
>>>
>>> Crash flow:
>>> ------
>>> fork13 run started
>>> BUG: Bad page map in process fork13
>>> BUG: Bad rss-counter state mm:
>>> Unable to handle kernel paging request at virtual address
>>> Internal error: Oops: 0000000096000046
>>> run for 800 secs ( 13 minutes) and more.
>>> fork14 run started and completed
>>>
>>> fpathconf01 run started and completed
>>> sugov:
>>>
>>> Unable to handle kernel NULL pointer dereference at virtual address
>>>
>>> Insufficient stack space to handle exception!
>>> end Kernel panic - not syncing: kernel stack overflow
>>>
>>> I have tried to decode stack dump by not being useful [1].
>>> [1] https://people.linaro.org/~naresh.kamboju/output-rk3399.txt
>>>
>>> Test log :
>>> --------
>>> tst_test.c:1733: TINFO: LTP version: 20240524
>>> tst_test.c:1617: TINFO: Timeout per run is 0h 15m 00s
>>> [  904.280569] BUG: Bad page map in process fork13  pte:2000000019ffc3
>>> pmd:80000000df55003
>>> [  904.281397] page: refcount:1 mapcount:-1 mapping:0000000000000000
>>> index:0x0 pfn:0x19f
>>
>> Mapcount underflow on a small folio (head: not printed).
>>
>> [...]
>>
>>> [  904.294564] BUG: Bad page map in process fork13  pte:200000002e4fc3
>>> pmd:80000000df55003
>>> [  904.295275] page: refcount:2 mapcount:-1 mapping:000000007885152f
>>> index:0x6 pfn:0x2e4
>>
>> Another mapcount underflow on a small folio (head: not printed).
>>
>>
>>> [  904.309309] BUG: Bad page map in process fork13  pte:20000000cc6fc3
>>> pmd:80000000df55003
>>> [  904.310031] page: refcount:1 mapcount:-1 mapping:0000000000000000
>>> index:0x6 pfn:0xcc6
>>> [  904.310728] head: order:3 mapcount:-1 entire_mapcount:0
>>> nr_pages_mapped:8388607 pincount:0
>>
>> Mapcount underflow on a large folio.
>>
>> ...
>>
>>> [  904.326666] BUG: Bad page map in process fork13  pte:20000000268fc3
>>> pmd:80000000df55003
>>> [  904.327390] page: refcount:1 mapcount:-1 mapping:00000000f0624181
>>> index:0x1b pfn:0x268
>>
>> Another mapcount underflow on a small folio (head: not printed).
>>
>>> [  904.328094] memcg:ffff0000016b4000
>>> [  904.328401] aops:nfs_file_aops ino:8526e6 dentry
>>> name:"libgpg-error.so.0.36.0"
>>> [  904.329051] flags:
>>> 0x3fffe000000002c(referenced|uptodate|lru|node=0|zone=0|lastcpupid=0x1ffff)
>>> [  904.329878] raw: 03fffe000000002c fffffdffc0009a48 fffffdffc022f3c8
>>> ffff00000688bd60
>>> [  904.330561] raw: 000000000000001b 0000000000000000 00000001fffffffe
>>> ffff0000016b4000
>>> [  904.331240] page dumped because: bad pte
>>> [  904.331590] addr:0000aaaad9afe000 vm_flags:00000075
>>> anon_vma:0000000000000000 mapping:ffff0000300d4188 index:2e
>>> [  904.332476] file:fork13 fault:filemap_fault mmap:nfs_file_mmap
>>> read_folio:nfs_read_folio
>>> [  904.333245] CPU: 5 PID: 22685 Comm: fork13 Tainted: G    B
>>
>>
>> Are these maybe side-effects due to
>>
>> https://lkml.kernel.org/r/20240607103241.1298388-1-wangkefeng.wang@huawei.com
> 
> IIUC, the rk3399-rock-pi-4b device has no NUMA nodes (6 arm64 cores), so
> I don't think the numa balancing will cause this issue.
> 
> Anyway, I will run fork13 test case on my arm64 server to try.

I have the faint recollection that we can (or at least could in the 
past) end up in do_numa_page() also without NUMA hinting.

I documented in 51d3d5eb74ff53b92dcff48b30ae2ed8edd85a32:

"
Note that do_numa_page() / do_huge_pmd_numa_page() can be reached even
without NUMA hinting (which currently doesn't seem to be applicable to
shmem), for example, by using uffd-wp with a PROT_WRITE shmem VMA.
"

But I don't remember all of the details, though.

-- 
Cheers,

David / dhildenb