FYI, we noticed the following commit (built with gcc-4.9):

commit: 67ffc906f8dee0e0433cad83dbdd198e5d1fc86f ("mm: Warn on lock_page() from reclaim context.")
url: https://github.com/0day-ci/linux/commits/Tetsuo-Handa/mm-Warn-on-lock_page-from-reclaim-context/20180318-173622


in testcase: trinity
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-x86_64 -enable-kvm -cpu host -smp 2 -m 1G

caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace):


+----------------------------------------------------------------+------------+------------+
|                                                                | 3266b5bd97 | 67ffc906f8 |
+----------------------------------------------------------------+------------+------------+
| boot_successes                                                 | 0          | 4          |
| boot_failures                                                  | 6          | 4          |
| invoked_oom-killer:gfp_mask=0x                                 | 4          | 4          |
| Mem-Info                                                       | 4          | 4          |
| Out_of_memory:Kill_process                                     | 4          | 4          |
| IP-Config:Auto-configuration_of_network_failed                 | 2          |            |
| WARNING:at_mm/filemap.c:#__warn_lock_page_from_reclaim_context | 0          | 4          |
| RIP:__warn_lock_page_from_reclaim_context                      | 0          | 4          |
+----------------------------------------------------------------+------------+------------+



[   60.841737] WARNING: CPU: 0 PID: 221 at mm/filemap.c:3335 __warn_lock_page_from_reclaim_context+0x15/0x20
[   60.848852] Modules linked in:
[   60.850212] CPU: 0 PID: 221 Comm: sed Not tainted 4.16.0-rc4-00340-g67ffc90 #2
[   60.853040] RIP: 0010:__warn_lock_page_from_reclaim_context+0x15/0x20
[   60.856077] RSP: 0000:ffff88000bf5f870 EFLAGS: 00010286
[   60.858240] RAX: 0000000000000000 RBX: 0000000000000002 RCX: ffffffff8110bd35
[   60.861127] RDX: dffffc0000000000 RSI: dffffc0000000000 RDI: 0000000000000282
[   60.863965] RBP: 0000000000000000 R08: 000000005be0c889 R09: 0000000000000000
[   60.866938] R10: 0000000000000000 R11: 0000000000000000 R12: ffff88000c0fd840
[   60.869848] R13: 0000000000000000 R14: ffff88000bcf2680 R15: ffffea000010f7c0
[   60.872731] FS:  00007f73274ca800(0000) GS:ffffffff8244e000(0000) knlGS:0000000000000000
[   60.875729] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   60.878035] CR2: 00007f7b80fd7f38 CR3: 000000000c1e2000 CR4: 00000000000006f0
[   60.880841] Call Trace:
[   60.881874]  pagecache_get_page+0x2b2/0x2c0
[   60.883571]  shmem_unused_huge_shrink+0x4f2/0x5f0
[   60.885514]  super_cache_scan+0x225/0x230
[   60.887111]  shrink_slab+0x265/0x3c0
[   60.888533]  shrink_node+0x5d4/0x610
[   60.890084]  do_try_to_free_pages+0x159/0x500
[   60.891717]  try_to_free_pages+0xe7/0x120
[   60.893268]  __alloc_pages_slowpath+0x497/0xd90
[   60.895089]  ? __schedule+0x377/0x810
[   60.896666]  __alloc_pages_nodemask+0x1c2/0x1f0
[   60.898644]  __handle_mm_fault+0x1394/0x1d20
[   60.900338]  handle_mm_fault+0x200/0x3e0
[   60.901835]  __do_page_fault+0x242/0x5e0
[   60.903406]  do_page_fault+0x50/0xc0
[   60.904944]  ? async_page_fault+0x2f/0x50
[   60.906446]  async_page_fault+0x45/0x50
[   60.907909] RIP: 5a30:          (null)
[   60.909415] RSP: 0b4c:00007ffc44e0a8d0 EFLAGS: 7ffc44e0a8e0
[   60.909430] Code: 28 74 05 e9 5e ff ff ff b8 ea ff ff ff c3 0f 1f 84 00 00 00 00 00 48 c7 c7 98 aa 26 82 31 c0 c6 05 5a 57 51 01 01 e8 fb 1f f0 ff <0f> 0b c3 0f 1f 84 00 00 00 00 00 80 3d 43 57 51 01 00 74 02 f3 
[   60.919927] ---[ end trace 27a931034e2c0f7c ]---


To reproduce:

        git clone https://github.com/intel/lkp-tests.git
        cd lkp-tests
        bin/lkp qemu -k <bzImage> job-script  # job-script is attached in this email



Thanks,
Xiaolong