FYI, we noticed the below changes on

https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git for-4.6/drivers
commit 868f2f0b72068a097508b6e8870a8950fd8eb7ef ("blk-mq: dynamic h/w context count")


+-------------------------------------------------------+------------+------------+
|                                                       | 3984aa5520 | 868f2f0b72 |
+-------------------------------------------------------+------------+------------+
| boot_successes                                        | 22         | 2          |
| boot_failures                                         | 0          | 64         |
| INFO:trying_to_register_non-static_key                | 0          | 52         |
| backtrace:do_mount                                    | 0          | 52         |
| backtrace:SyS_mount                                   | 0          | 52         |
| BUG:unable_to_handle_kernel                           | 0          | 12         |
| Oops                                                  | 0          | 12         |
| RIP:blk_mq_init_allocated_queue                       | 0          | 6          |
| Kernel_panic-not_syncing:Fatal_exception              | 0          | 9          |
| backtrace:blk_mq_init_allocated_queue                 | 0          | 6          |
| backtrace:blk_mq_init_queue                           | 0          | 6          |
| backtrace:init                                        | 0          | 6          |
| backtrace:kernel_init_freeable                        | 0          | 6          |
| Kernel_panic-not_syncing:Fatal_exception_in_interrupt | 0          | 3          |
| RIP:__lock_acquire                                    | 0          | 4          |
| RIP:do_raw_spin_trylock                               | 0          | 1          |
| backtrace:cpu_startup_entry                           | 0          | 2          |
| backtrace:vmstat_shepherd                             | 0          | 3          |
+-------------------------------------------------------+------------+------------+



[   10.685723] pidof (165) used greatest stack depth: 14016 bytes left
[   11.087599] logger (465) used greatest stack depth: 13944 bytes left
[   11.182853] UDF-fs: warning (device vdb): udf_fill_super: No partition found (2)
[   11.196223] INFO: trying to register non-static key.
[   11.197332] the code is fine but needs lockdep annotation.
[   11.198502] turning off the locking correctness validator.
[   11.199679] CPU: 0 PID: 515 Comm: mount Not tainted 4.5.0-rc2-00005-g868f2f0 #120
[   11.201365] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Debian-1.8.2-1 04/01/2014
[   11.203331]  0000000000000000 ffff88000dd2fa78 ffffffff813eeaf0 0000000000000000
[   11.205100]  ffff88000dd2fae0 ffffffff810ad496 ffffffff81039aa5 ffff88000dd2faa0
[   11.206961]  0000000181039acb 0000000000000000 00000000000002d0 0000000000000000
[   11.209175] Call Trace:
[   11.209603] UDF-fs: warning (device vda): udf_fill_super: No partition found (2)
[   11.211190]  [<ffffffff813eeaf0>] dump_stack+0x4b/0x6c
[   11.212236]  [<ffffffff810ad496>] __lock_acquire+0x77d/0xc27
[   11.213652]  [<ffffffff81039aa5>] ? kvm_clock_read+0x25/0x37
[   11.214883]  [<ffffffff810ae0e6>] lock_acquire+0x53/0x76
[   11.216006]  [<ffffffff813d9fe0>] ? blk_insert_flush+0x182/0x1c5
[   11.217275]  [<ffffffff81c73513>] _raw_spin_lock_irq+0x36/0x6c
[   11.218510]  [<ffffffff813d9fe0>] ? blk_insert_flush+0x182/0x1c5
[   11.219888]  [<ffffffff813d9fe0>] blk_insert_flush+0x182/0x1c5
[   11.221326]  [<ffffffff813e01cb>] blk_sq_make_request+0xf7/0x23c
[   11.222698]  [<ffffffff813d674f>] generic_make_request+0xb8/0x156
[   11.224165]  [<ffffffff813d68d8>] submit_bio+0xeb/0xf6
[   11.225321]  [<ffffffff810a6dc1>] ? __init_waitqueue_head+0x36/0x49
[   11.226738]  [<ffffffff813d1e67>] submit_bio_wait+0x4f/0x65
[   11.228201]  [<ffffffff813da080>] blkdev_issue_flush+0x5d/0x7f
[   11.229617]  [<ffffffff812cd1bd>] xfs_blkdev_issue_flush+0x14/0x16
[   11.230991]  [<ffffffff812b9621>] xfs_free_buftarg+0x35/0x42
[   11.232279]  [<ffffffff812cbd1e>] xfs_close_devices+0x5f/0x64
[   11.233489]  [<ffffffff812ccca4>] xfs_fs_fill_super+0x318/0x4e3
[   11.234769]  [<ffffffff81156bbe>] mount_bdev+0x13e/0x193
[   11.235889]  [<ffffffff812cc98c>] ? xfs_parseargs+0x8bd/0x8bd
[   11.237107]  [<ffffffff812cb317>] xfs_fs_mount+0x10/0x12
[   11.238223]  [<ffffffff81156db0>] mount_fs+0xf/0x87
[   11.239245]  [<ffffffff8116eee9>] vfs_kern_mount+0x65/0x138
[   11.240484]  [<ffffffff81170de1>] do_mount+0xa1c/0xba6
[   11.241644]  [<ffffffff8111233e>] ? strndup_user+0x3a/0x54
[   11.242866]  [<ffffffff81171173>] SyS_mount+0x72/0x9a
[   11.244163]  [<ffffffff81c73f76>] entry_SYSCALL_64_fastpath+0x16/0x7a
[   11.259529] NILFS: Can't find nilfs on dev vdb.





Thanks,
Kernel Test Robot