FYI, we noticed the following commit:

commit: b3bd18069659cd4f4cdb0ea1638f4ce54ef0b499 ("VFS: Implement a superblock configuration context")
https://git.kernel.org/cgit/linux/kernel/git/dhowells/linux-fs.git mount-context

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 -smp 2 -m 512M

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


+------------------------------------------------+------------+------------+
|                                                | 50f1960a2b | b3bd180696 |
+------------------------------------------------+------------+------------+
| boot_successes                                 | 7          | 0          |
| boot_failures                                  | 0          | 6          |
| BUG:stack_guard_page_was_hit_at#(stack_is#..#) | 0          | 6          |
| Kernel_panic-not_syncing:Fatal_exception       | 0          | 6          |
+------------------------------------------------+------------+------------+



[    1.018960] BUG: stack guard page was hit at ffffa662400d4000 (stack is ffffa662400d0000..ffffa662400d3fff)
[    1.021514] kernel stack overflow (page fault): 0000 [#1] SMP
[    1.022918] Modules linked in:
[    1.024023] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.12.0-rc1-00009-gb3bd180 #4
[    1.026254] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.9.3-20161025_171302-gandalf 04/01/2014
[    1.028802] task: ffff969a91900040 task.stack: ffffa662400d0000
[    1.030144] RIP: 0010:legacy_monolithic_mount_data+0x66/0xa0
[    1.031546] RSP: 0000:ffffa662400d3db8 EFLAGS: 00010246
[    1.032955] RAX: ffff969a9172a2a8 RBX: ffff969a90915d08 RCX: 000000000000038e
[    1.034620] RDX: 0000000000001000 RSI: ffffa662400d3ffe RDI: ffff969a9172a470
[    1.036311] RBP: ffffa662400d3dd0 R08: 00000000a444cb27 R09: 0000000000000001
[    1.037925] R10: ffffa662400d3d38 R11: ffffa662400d3e3f R12: 0000000000000000
[    1.039578] R13: ffffa662400d3e36 R14: ffffffff9472cfe0 R15: 0000000000000800
[    1.041235] FS:  0000000000000000(0000) GS:ffff969a92c00000(0000) knlGS:0000000000000000
[    1.043402] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[    1.044963] CR2: ffffa662400d4000 CR3: 0000000009423000 CR4: 00000000000006f0
[    1.046509] Call Trace:
[    1.047440]  parse_monolithic_mount_data+0x20/0x22
[    1.048753]  vfs_kern_mount+0x4c/0xb4
[    1.049786]  kern_mount_data+0x19/0x2e
[    1.050876]  init_hugetlbfs_fs+0xe3/0x15a
[    1.051980]  ? proc_create_data+0x86/0x9f
[    1.053209]  ? init_ramfs_fs+0x25/0x25
[    1.054354]  ? set_debug_rodata+0x17/0x17
[    1.055483]  do_one_initcall+0x90/0x13c
[    1.069483]  ? set_debug_rodata+0x17/0x17
[    1.070703]  kernel_init_freeable+0x1de/0x261
[    1.071965]  ? rest_init+0x13b/0x13b
[    1.073007]  kernel_init+0xe/0xf5
[    1.074112]  ret_from_fork+0x31/0x40
[    1.075120] Code: e8 e3 5a 37 00 eb 54 45 31 e4 48 85 f6 49 89 f5 74 49 48 83 7f 50 00 48 89 fb 74 1a b9 00 04 00 00 48 8b 7b 50 4c 89 ee 45 31 e4 <f3> a5 c7 43 60 00 10 00 00 eb 25 48 8b 3d 1b bf 4b 02 ba 00 10 
[    1.079546] RIP: legacy_monolithic_mount_data+0x66/0xa0 RSP: ffffa662400d3db8
[    1.081175] ---[ end trace 89195d162e5195f6 ]---


To reproduce:

        git clone https://github.com/01org/lkp-tests.git
        cd lkp-tests
        bin/lkp qemu -k <bzImage> job-script  # job-script is attached in this email



Thanks,
Kernel Test Robot