Re: [mm/debug_vm_pgtable/locks] e2aad6f1d2: BUG:unable_to_handle_page_fault_for_address

[Anshuman Khandual]

On 09/22/2020 09:33 AM, Aneesh Kumar K.V wrote:
> On 9/21/20 2:51 PM, kernel test robot wrote:
>> Greeting,
>>
>> FYI, we noticed the following commit (built with gcc-9):
>>
>> commit: e2aad6f1d232b457ea6a3194992dd4c0a83534a5 ("mm/debug_vm_pgtable/locks: take correct page table lock")
>> https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git master
>>
>>
>> in testcase: trinity
>> version: trinity-i386
>> with following parameters:
>>
>>     runtime: 300s
>>
>> test-description: Trinity is a linux system call fuzz tester.
>> test-url: http://codemonkey.org.uk/projects/trinity/
>>
>>
>> on test machine: qemu-system-i386 -enable-kvm -cpu SandyBridge -smp 2 -m 8G
>>
>> caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace):
>>
>>
>> +----------------------------------------------------------------------+------------+------------+
>> |                                                                      | c50eb1ed65 | e2aad6f1d2 |
>> +----------------------------------------------------------------------+------------+------------+
>> | boot_successes                                                       | 0          | 0          |
>> | boot_failures                                                        | 61         | 17         |
>> | BUG:workqueue_lockup-pool                                            | 1          |            |
>> | BUG:sleeping_function_called_from_invalid_context_at_mm/page_alloc.c | 60         | 17         |
>> | BUG:unable_to_handle_page_fault_for_address                          | 0          | 17         |
>> | Oops:#[##]                                                           | 0          | 17         |
>> | EIP:ptep_get                                                         | 0          | 17         |
>> | Kernel_panic-not_syncing:Fatal_exception                             | 0          | 17         |
>> +----------------------------------------------------------------------+------------+------------+
>>
>>
>> If you fix the issue, kindly add following tag
>> Reported-by: kernel test robot <rong.a.chen@xxxxxxxxx>
>>
>>
>> [   28.726464] BUG: sleeping function called from invalid context at mm/page_alloc.c:4822
>> [   28.727835] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 1, name: swapper
>> [   28.729221] no locks held by swapper/1.
>> [   28.729954] CPU: 0 PID: 1 Comm: swapper Not tainted 5.9.0-rc3-00324-ge2aad6f1d232b4 #1
>> [   28.731484] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
>> [   28.732891] Call Trace:
>> [   28.733295]  ? show_stack+0x48/0x50
>> [   28.733943]  dump_stack+0x1b/0x1d
>> [   28.734569]  ___might_sleep+0x205/0x219
>> [   28.735292]  __might_sleep+0x106/0x10f
>> [   28.736022]  __alloc_pages_nodemask+0xe0/0x2c8
>> [   28.736845]  swap_migration_tests+0x62/0x295
>> [   28.737639]  debug_vm_pgtable+0x587/0x9b5
>> [   28.738374]  ? pte_advanced_tests+0x267/0x267
>> [   28.739318]  do_one_initcall+0x129/0x31c
>> [   28.740023]  ? rcu_read_lock_sched_held+0x46/0x74
>> [   28.740944]  kernel_init_freeable+0x201/0x250
>> [   28.741763]  ? rest_init+0xf8/0xf8
>> [   28.742401]  kernel_init+0xe/0x15d
>> [   28.743040]  ? rest_init+0xf8/0xf8
>> [   28.743694]  ret_from_fork+0x1c/0x30
> 
> 
> This should be fixed by
> https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/mm/debug_vm_pgtable.c?id=3a4f9a45eadb6ed5fc04686e8db4dc7bb1caec44
> 
>> [   28.744364] BUG: unable to handle page fault for address: fffbbea4
>> [   28.745465] #PF: supervisor read access in kernel mode
>> [   28.746373] #PF: error_code(0x0000) - not-present page
>> [   28.747275] *pde = 0492b067 *pte = 00000000
>> [   28.748054] Oops: 0000 [#1]
>> [   28.748548] CPU: 0 PID: 1 Comm: swapper Tainted: G        W         5.9.0-rc3-00324-ge2aad6f1d232b4 #1
>> [   28.750188] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
>> [   28.751641] EIP: ptep_get+0x0/0x3
>> [   28.752226] Code: 5d fc c9 c3 55 c1 e8 1a 89 e5 53 31 db 83 f8 1f 6a 00 0f 94 c3 b8 80 67 02 c4 31 c9 89 da e8 16 5c f1 ff 89 d8 8b 5d fc c9 c3 <8b> 00 c3 55 31 c9 89 e5 57 56 53 8b 70 04 89 c3 b8 10 68 02 c4 6a
>> [   28.755465] EAX: fffbbea4 EBX: fffbbea4 ECX: 000047bd EDX: fffbbea4
>> [   28.756418] ESI: 000047bd EDI: 00000025 EBP: f406bed8 ESP: f406bebc
>> [   28.757522] DS: 007b ES: 007b FS: 0000 GS: 0000 SS: 0068 EFLAGS: 00010286
>> [   28.758739] CR0: 80050033 CR2: fffbbea4 CR3: 04928000 CR4: 000406d0
>> [   28.759828] Call Trace:
>> [   28.760235]  ? hugetlb_advanced_tests+0x2a/0x27f
>> [   28.761099]  ? do_raw_spin_unlock+0xd7/0x112
>> [   28.761872]  debug_vm_pgtable+0x927/0x9b5
>> [   28.762578]  ? pte_advanced_tests+0x267/0x267
>> [   28.763462]  do_one_initcall+0x129/0x31c
>> [   28.764134]  ? rcu_read_lock_sched_held+0x46/0x74
>> [   28.764948]  kernel_init_freeable+0x201/0x250
>> [   28.765654]  ? rest_init+0xf8/0xf8
>> [   28.766277]  kernel_init+0xe/0x15d
>> [   28.766878]  ? rest_init+0xf8/0xf8
>> [   28.767488]  ret_from_fork+0x1c/0x30
>> [   28.768052] Modules linked in:
>> [   28.768532] CR2: 00000000fffbbea4
>> [   28.769065] ---[ end trace 9c4395cf49c7b3e7 ]---
>>
> 
> IIUC, Anshuman is reworking the test to follow the page table update rules.

The failure here has been attributed to this particular patch, and
IIRC we did not see this particular failure before this series.