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Message-ID: <7cfe60a2-cd8e-4af2-a5d9-6c790b6dd665@linux.alibaba.com>
Date: Wed, 12 Jun 2024 09:40:51 +0800
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Subject: Re: LTP: fork13: kernel panic on rk3399-rock-pi-4 running mainline
 6.10.rc3
To: David Hildenbrand <david@redhat.com>,
 Naresh Kamboju <naresh.kamboju@linaro.org>,
 open list <linux-kernel@vger.kernel.org>, linux-mm <linux-mm@kvack.org>,
 lkft-triage@lists.linaro.org, Linux Regressions <regressions@lists.linux.dev>
Cc: Andrew Morton <akpm@linux-foundation.org>, willy@infradead.org,
 Kefeng Wang <wangkefeng.wang@huawei.com>, Barry Song <baohua@kernel.org>,
 Ryan Roberts <ryan.roberts@arm.com>,
 "Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>,
 Dan Carpenter <dan.carpenter@linaro.org>, Arnd Bergmann <arnd@arndb.de>,
 Anders Roxell <anders.roxell@linaro.org>
References: <CA+G9fYvKmr84WzTArmfaypKM9+=Aw0uXCtuUKHQKFCNMGJyOgQ@mail.gmail.com>
 <e8c10a52-61f9-4b46-bc50-e2c267b1aa56@redhat.com>
 <80a05784-21dd-4f20-b441-1e2a2be0e0ff@linux.alibaba.com>
 <3ce90ee2-f51b-49fc-b010-f97e61e617f4@redhat.com>
From: Baolin Wang <baolin.wang@linux.alibaba.com>
In-Reply-To: <3ce90ee2-f51b-49fc-b010-f97e61e617f4@redhat.com>
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On 2024/6/11 20:09, David Hildenbrand wrote:
> 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.
> "

I see. Thanks for explanation.