FYI, we noticed the following commit (built with gcc-6):

commit: 6393e11b84a5116ea99d7a05d0dcada2acea347f ("kernfs, sysfs, cgroup, intel_rdt: Support fs_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-i386 -enable-kvm -m 256M

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


+------------------------------------------+------------+------------+
|                                          | 33f54afb25 | 6393e11b84 |
+------------------------------------------+------------+------------+
| boot_successes                           | 8          | 2          |
| boot_failures                            | 0          | 6          |
| kernel_BUG_at_fs/super.c                 | 0          | 6          |
| invalid_opcode:#[##]                     | 0          | 6          |
| EIP:vfs_get_tree                         | 0          | 6          |
| Kernel_panic-not_syncing:Fatal_exception | 0          | 6          |
+------------------------------------------+------------+------------+



[   10.046412] kernel BUG at fs/super.c:1716!
[   10.046901] invalid opcode: 0000 [#1] PREEMPT DEBUG_PAGEALLOC
[   10.047397] Modules linked in:
[   10.047721] CPU: 0 PID: 1 Comm: init Not tainted 4.16.0-rc4-00170-g6393e11 #129
[   10.048344] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
[   10.049062] EIP: vfs_get_tree+0x5c/0xee
[   10.049399] EFLAGS: 00010286 CPU: 0
[   10.049774] EAX: 00000030 EBX: c9d00a00 ECX: 00000001 EDX: 0000001c
[   10.050318] ESI: 00000000 EDI: c1798780 EBP: 00000027 ESP: c0027f14
[   10.050859]  DS: 007b ES: 007b FS: 0000 GS: 00e0 SS: 0068
[   10.051327] CR0: 80050033 CR2: b7ef4588 CR3: 09d91d80 CR4: 000006b0
[   10.051919] Call Trace:
[   10.052140]  ? do_mount+0x8a7/0xab0
[   10.052454]  ? memdup_user+0x36/0x4e
[   10.052776]  ? SyS_mount+0x52/0x72
[   10.053076]  ? do_int80_syscall_32+0x57/0xc9
[   10.053467]  ? entry_INT80_32+0x31/0x31
[   10.053854] Code: f0 e9 ae 00 00 00 8b 13 89 d8 ff 52 18 85 c0 0f 88 9f 00 00 00 8b 43 08 85 c0 75 11 8b 43 04 ff 30 68 f3 6f 6b c1 e8 5a 58 f7 ff <0f> 0b 8b b0 84 00 00 00 83 be 9c 00 00 00 00 75 02 0f 0b 8b 43
[   10.055480] EIP: vfs_get_tree+0x5c/0xee SS:ESP: 0068:c0027f14
[   10.056043] ---[ end trace 1d2e9a62012a7a13 ]---


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,
lkp