[lkp-robot] [net] 37b927536f: kernel_BUG_at_net/core/net_namespace.c

FYI, we noticed the following commit (built with gcc-7):

commit: 37b927536f46b27de240934db9580c3d3eba9937 ("net: Introduce net_sem for protection of pernet_list")
url: https://github.com/0day-ci/linux/commits/Kirill-Tkhai/Replacing-net_mutex-with-rw_semaphore/20180215-064145


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 -m 512M

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


+------------------------------------------+------------+------------+
|                                          | b6d8347bf7 | 37b927536f |
+------------------------------------------+------------+------------+
| boot_successes                           | 8          | 0          |
| boot_failures                            | 0          | 8          |
| kernel_BUG_at_net/core/net_namespace.c   | 0          | 8          |
| invalid_opcode:#[##]                     | 0          | 8          |
| RIP:ops_init                             | 0          | 8          |
| Kernel_panic-not_syncing:Fatal_exception | 0          | 8          |
+------------------------------------------+------------+------------+



[    0.258559] kernel BUG at net/core/net_namespace.c:73!
[    0.260018] invalid opcode: 0000 [#1]
[    0.261073] Modules linked in:
[    0.262005] CPU: 0 PID: 1 Comm: swapper Not tainted 4.15.0-05871-g37b9275 #1
[    0.263875] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
[    0.266084] RIP: 0010:ops_init+0x101/0x120
[    0.267233] RSP: 0000:ffffc9000000be00 EFLAGS: 00010246
[    0.268647] RAX: 0000000000000000 RBX: ffffffff823280a0 RCX: 0000000000000000
[    0.270000] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88001c602180
[    0.270000] RBP: ffff88001c602140 R08: ffffffff82323d00 R09: ffff88001c602140
[    0.270000] R10: ffffffff82323308 R11: ffffffff827ff64d R12: ffffffff82323400
[    0.270000] R13: 0000000000000003 R14: ffffffff826e17b9 R15: 0000000000000000
[    0.270000] FS:  0000000000000000(0000) GS:ffffffff82235000(0000) knlGS:0000000000000000
[    0.270000] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[    0.270000] CR2: 0000000000000000 CR3: 0000000002213000 CR4: 00000000000006b0
[    0.270000] Call Trace:
[    0.270000]  ? set_debug_rodata+0x11/0x11
[    0.270000]  register_pernet_operations+0x101/0x1e0
[    0.270000]  register_pernet_subsys+0x24/0x40
[    0.270000]  netlink_proto_init+0x143/0x160
[    0.270000]  ? eth_offload_init+0x14/0x14
[    0.270000]  do_one_initcall+0x4d/0x190
[    0.270000]  kernel_init_freeable+0x10e/0x190
[    0.270000]  ? rest_init+0xa0/0xa0
[    0.270000]  kernel_init+0xa/0xf0
[    0.270000]  ret_from_fork+0x3a/0x50
[    0.270000] Code: 8d 14 c5 e8 ff ff ff e8 be 14 11 00 4b 89 2c ef 49 8d 7e 08 4d 89 bc 24 50 06 00 00 be 08 00 00 00 e8 34 22 95 ff e9 77 ff ff ff <0f> 0b 0f 0b b8 f4 ff ff ff eb 91 b8 f4 ff ff ff e9 77 ff ff ff 
[    0.270000] RIP: ops_init+0x101/0x120 RSP: ffffc9000000be00
[    0.270013] ---[ end trace e0045ead2b146f98 ]---


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