Re: [lkp-robot] [rcu] b332151a29: kernel_BUG_at

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* Re: [lkp-robot] [rcu]  b332151a29: kernel_BUG_at_mm/slab.c
       [not found] <20170119010216.GA8287@yexl-desktop>
@ 2017-01-20 16:01 ` Sebastian Andrzej Siewior
  2017-01-20 16:09   ` Jens Axboe
  0 siblings, 1 reply; 6+ messages in thread
From: Sebastian Andrzej Siewior @ 2017-01-20 16:01 UTC (permalink / raw)
  To: kernel test robot, Jens Axboe
  Cc: Paul E. McKenney, LKML, lkp, linux-scsi, tglx, linux-block

On 2017-01-19 09:02:16 [+0800], kernel test robot wrote:
> test-description: Trinity is a linux system call fuzz tester.

you don't even get to fire up trinity. With and without the patch you
crash very early.

> +-----------------------------------------------------+------------+------------+
> |                                                     | d5f6ab9c11 | b332151a29 |
> +-----------------------------------------------------+------------+------------+
> | boot_successes                                      | 0          | 0          |
> | boot_failures                                       | 6          | 8          |
> | WARNING:at_include/linux/kref.h:#kobject_get        | 6          | 8          |
> | WARNING:at_arch/x86/mm/dump_pagetables.c:#note_page | 2          | 2          |
> | kernel_BUG_at_mm/slab.c                             | 0          | 4          |
> | invalid_opcode:#[##]PREEMPT_SMP                     | 0          | 4          |
> | Kernel_panic-not_syncing:Fatal_exception            | 0          | 6          |
> | BUG:unable_to_handle_kernel                         | 0          | 2          |
> | Oops                                                | 0          | 2          |
> +-----------------------------------------------------+------------+------------+

There is no successful boot. The pattern changes with patch in question
applied.

> [    8.044624] sd 0:0:0:0: [sda] Synchronizing SCSI cache
> [    8.055721] slab: double free detected in cache 'kmalloc-32', objp 8af558c0
> [    8.057138] ------------[ cut here ]------------
> [    8.058085] kernel BUG at mm/slab.c:2624!
> [    8.059255] invalid opcode: 0000 [#1] PREEMPT SMP

yes. With and without the patch there is a lot of wrong stuff like
complains about a kobject initialized again. This leads to a double free
at some point.

What happens is the following: CONFIG_SCSI_DEBUG is enabled which adds a
dummy host controller with a dummy disk. This gets probed during boot.
Since you also enabled CONFIG_DEBUG_TEST_DRIVER_REMOVE it gets removed
and re-added. The request_queue in genhd disk is re-used while the disk
is added for the second time:

[    1.314404] scsi host0: scsi_debug: version 1.86 [20160430]
[    1.314404]   dev_size_mb=8, opts=0x0, submit_queues=1, statistics=0
[    1.315994] scsi 0:0:0:0: Direct-Access     Linux    scsi_debug       0186 PQ: 0 ANSI: 7
[    1.351052] sd 0:0:0:0: [sda] 16384 512-byte logical blocks: (8.39 MB/8.00 MiB)
[    1.355916] sd 0:0:0:0: [sda] Write Protect is off
[    1.356838] sd 0:0:0:0: [sda] Mode Sense: 73 00 10 08
[    1.364455] sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, supports DPO and FUA
[    1.437642] sd 0:0:0:0: [sda] Attached SCSI disk
[    1.438413] sd 0:0:0:0: [sda] Synchronizing SCSI cache
[    1.445868] sd 0:0:0:0: [sda] 16384 512-byte logical blocks: (8.39 MB/8.00 MiB)
[    1.450819] sd 0:0:0:0: [sda] Write Protect is off
[    1.451853] sd 0:0:0:0: [sda] Mode Sense: 73 00 10 08
[    1.459636] sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, supports DPO and FUA
[    1.471446] kobject (beb87d44): tried to init an initialized object, something is seriously wrong.

Since you also need CONFIG_SCSI_MQ_DEFAULT enabled I assume the MQ block
code is buggy here.
But commit b332151a29 in Paul's tree innocent.

Sebastian

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [lkp-robot] [rcu] b332151a29: kernel_BUG_at_mm/slab.c
  2017-01-20 16:01 ` [lkp-robot] [rcu] b332151a29: kernel_BUG_at_mm/slab.c Sebastian Andrzej Siewior
@ 2017-01-20 16:09   ` Jens Axboe
  2017-01-20 16:23     ` Sebastian Andrzej Siewior
  0 siblings, 1 reply; 6+ messages in thread
From: Jens Axboe @ 2017-01-20 16:09 UTC (permalink / raw)
  To: Sebastian Andrzej Siewior, kernel test robot
  Cc: Paul E. McKenney, LKML, lkp, linux-scsi, tglx, linux-block

On 01/20/2017 08:01 AM, Sebastian Andrzej Siewior wrote:
> On 2017-01-19 09:02:16 [+0800], kernel test robot wrote:
>> test-description: Trinity is a linux system call fuzz tester.
> 
> you don't even get to fire up trinity. With and without the patch you
> crash very early.
> 
>> +-----------------------------------------------------+------------+------------+
>> |                                                     | d5f6ab9c11 | b332151a29 |
>> +-----------------------------------------------------+------------+------------+
>> | boot_successes                                      | 0          | 0          |
>> | boot_failures                                       | 6          | 8          |
>> | WARNING:at_include/linux/kref.h:#kobject_get        | 6          | 8          |
>> | WARNING:at_arch/x86/mm/dump_pagetables.c:#note_page | 2          | 2          |
>> | kernel_BUG_at_mm/slab.c                             | 0          | 4          |
>> | invalid_opcode:#[##]PREEMPT_SMP                     | 0          | 4          |
>> | Kernel_panic-not_syncing:Fatal_exception            | 0          | 6          |
>> | BUG:unable_to_handle_kernel                         | 0          | 2          |
>> | Oops                                                | 0          | 2          |
>> +-----------------------------------------------------+------------+------------+
> 
> There is no successful boot. The pattern changes with patch in question
> applied.
> 
>> [    8.044624] sd 0:0:0:0: [sda] Synchronizing SCSI cache
>> [    8.055721] slab: double free detected in cache 'kmalloc-32', objp 8af558c0
>> [    8.057138] ------------[ cut here ]------------
>> [    8.058085] kernel BUG at mm/slab.c:2624!
>> [    8.059255] invalid opcode: 0000 [#1] PREEMPT SMP

Is there a full trace of this?

> yes. With and without the patch there is a lot of wrong stuff like
> complains about a kobject initialized again. This leads to a double free
> at some point.

And what patch are we talking about? I don't mind being CC'ed into a thread,
but some context and background would be immensely helpful here...

-- 
Jens Axboe

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [lkp-robot] [rcu] b332151a29: kernel_BUG_at_mm/slab.c
  2017-01-20 16:09   ` Jens Axboe
@ 2017-01-20 16:23     ` Sebastian Andrzej Siewior
  2017-01-20 16:32       ` Jens Axboe
  0 siblings, 1 reply; 6+ messages in thread
From: Sebastian Andrzej Siewior @ 2017-01-20 16:23 UTC (permalink / raw)
  To: Jens Axboe
  Cc: kernel test robot, Paul E. McKenney, LKML, lkp, linux-scsi, tglx,
	linux-block

On 2017-01-20 08:09:36 [-0800], Jens Axboe wrote:
> Is there a full trace of this?

[    3.654003] scsi host0: scsi_debug: version 1.86 [20160430]
[    3.654003]   dev_size_mb=8, opts=0x0, submit_queues=1, statistics=0
[    3.660755] scsi 0:0:0:0: Direct-Access     Linux    scsi_debug       0186 PQ: 0 ANSI: 7
[    3.711231] sd 0:0:0:0: [sda] 16384 512-byte logical blocks: (8.39 MB/8.00 MiB)
[    3.716202] sd 0:0:0:0: [sda] Write Protect is off
[    3.717244] sd 0:0:0:0: [sda] Mode Sense: 73 00 10 08
[    3.725059] sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, supports DPO and FUA
[    3.795093] sd 0:0:0:0: [sda] Attached SCSI disk
[    3.796686] sd 0:0:0:0: [sda] Synchronizing SCSI cache
[    3.804770] sd 0:0:0:0: [sda] 16384 512-byte logical blocks: (8.39 MB/8.00 MiB)
[    3.809748] sd 0:0:0:0: [sda] Write Protect is off
[    3.810806] sd 0:0:0:0: [sda] Mode Sense: 73 00 10 08
[    3.818599] sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, supports DPO and FUA
[    3.830894] kobject (be01a5fc): tried to init an initialized object, something is seriously wrong.
[    3.832820] CPU: 6 PID: 6 Comm: kworker/u14:0 Not tainted 4.9.0 #86
[    3.834172] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.10.1-1 04/01/2014
[    3.835886] Workqueue: events_unbound async_run_entry_fn
[    3.837028]  80079da8 83a5f6cc be01a5fc be01a5fc 80079dc4 83a61e33 842a883c be01a5fc
[    3.838802]  ffffffff 84397488 be01a108 80079dec 83a46afa be01a5d8 840670a0 be01a5d8
[    3.840570]  be01a108 bd983468 be01a108 bd983470 be01a5d8 80079e14 83a3c857 be01a5d8
[    3.842350] Call Trace:
[    3.842884]  [<83a5f6cc>] dump_stack+0x58/0x7c
[    3.843834]  [<83a61e33>] kobject_init+0x73/0x80
[    3.844828]  [<83a46afa>] blk_mq_register_dev+0x2a/0x110
[    3.845971]  [<83a3c857>] blk_register_queue+0x87/0x140
[    3.847085]  [<83a49c7e>] device_add_disk+0x1ce/0x470
[    3.848170]  [<83c3d328>] sd_probe_async+0xe8/0x1b0
[    3.849207]  [<83672347>] async_run_entry_fn+0x37/0xe0
[    3.850313]  [<836694f7>] process_one_work+0x1b7/0x3e0
[    3.851414]  [<8366947c>] ? process_one_work+0x13c/0x3e0
[    3.852552]  [<83669759>] worker_thread+0x39/0x460
[    3.853569]  [<83669720>] ? process_one_work+0x3e0/0x3e0
[    3.854717]  [<8366f394>] kthread+0xb4/0xd0
[    3.855611]  [<83f8cb4d>] ? _raw_spin_unlock_irq+0x2d/0x50
[    3.856775]  [<8366f2e0>] ? __kthread_create_on_node+0x160/0x160
[    3.858066]  [<8366f2e0>] ? __kthread_create_on_node+0x160/0x160
[    3.859340]  [<83f8d363>] ret_from_fork+0x1b/0x28
[    3.863951] kobject (ff0ca36c): tried to init an initialized object, something is seriously wrong.
[    3.865875] CPU: 6 PID: 6 Comm: kworker/u14:0 Not tainted 4.9.0 #86
[    3.867202] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.10.1-1 04/01/2014
[    3.868924] Workqueue: events_unbound async_run_entry_fn
[    3.870079]  80079da8 83a5f6cc ff0ca36c be01a5fc 80079dc4 83a61e33 842a883c ff0ca36c
[    3.871846]  80079dc4 84397474 be01a108 80079dec 83a46b1c be01a5d8 840670a0 be01a5d8
[    3.873605]  be01a108 bd983468 be01a108 bd983470 be01a5d8 80079e14 83a3c857 be01a5d8
[    3.875395] Call Trace:
[    3.875928]  [<83a5f6cc>] dump_stack+0x58/0x7c
[    3.876878]  [<83a61e33>] kobject_init+0x73/0x80
[    3.877884]  [<83a46b1c>] blk_mq_register_dev+0x4c/0x110
[    3.879018]  [<83a3c857>] blk_register_queue+0x87/0x140
[    3.880136]  [<83a49c7e>] device_add_disk+0x1ce/0x470
[    3.881227]  [<83c3d328>] sd_probe_async+0xe8/0x1b0
[    3.882283]  [<83672347>] async_run_entry_fn+0x37/0xe0
[    3.883381]  [<836694f7>] process_one_work+0x1b7/0x3e0
[    3.884481]  [<8366947c>] ? process_one_work+0x13c/0x3e0
[    3.885613]  [<83669759>] worker_thread+0x39/0x460
[    3.886658]  [<83669720>] ? process_one_work+0x3e0/0x3e0
[    3.887791]  [<8366f394>] kthread+0xb4/0xd0
[    3.888680]  [<83f8cb4d>] ? _raw_spin_unlock_irq+0x2d/0x50
[    3.889881]  [<8366f2e0>] ? __kthread_create_on_node+0x160/0x160
[    3.891189]  [<8366f2e0>] ? __kthread_create_on_node+0x160/0x160
[    3.892506]  [<83f8d363>] ret_from_fork+0x1b/0x28
[    3.893563] kobject (ff21b36c): tried to init an initialized object, something is seriously wrong.
[    3.895559] CPU: 6 PID: 6 Comm: kworker/u14:0 Not tainted 4.9.0 #86
[    3.896938] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.10.1-1 04/01/2014
[    3.898741] Workqueue: events_unbound async_run_entry_fn
[    3.899911]  80079da8 83a5f6cc ff21b36c be01a5fc 80079dc4 83a61e33 842a883c ff21b36c
[    3.901739]  80079dc4 84397474 be01a108 80079dec 83a46b1c be01a5d8 840670a0 be01a5d8
[    3.903558]  be01a108 bd983468 be01a108 bd983470 be01a5d8 80079e14 83a3c857 be01a5d8
[    3.905381] Call Trace:
[    3.905936]  [<83a5f6cc>] dump_stack+0x58/0x7c
[    3.906913]  [<83a61e33>] kobject_init+0x73/0x80
[    3.907931]  [<83a46b1c>] blk_mq_register_dev+0x4c/0x110
[    3.909108]  [<83a3c857>] blk_register_queue+0x87/0x140
[    3.910267]  [<83a49c7e>] device_add_disk+0x1ce/0x470
[    3.911387]  [<83c3d328>] sd_probe_async+0xe8/0x1b0
[    3.912466]  [<83672347>] async_run_entry_fn+0x37/0xe0
[    3.913596]  [<836694f7>] process_one_work+0x1b7/0x3e0
[    3.914735]  [<8366947c>] ? process_one_work+0x13c/0x3e0
[    3.915916]  [<83669759>] worker_thread+0x39/0x460
[    3.916977]  [<83669720>] ? process_one_work+0x3e0/0x3e0
[    3.918159]  [<8366f394>] kthread+0xb4/0xd0
[    3.919097]  [<83f8cb4d>] ? _raw_spin_unlock_irq+0x2d/0x50
[    3.920322]  [<8366f2e0>] ? __kthread_create_on_node+0x160/0x160
[    3.921656]  [<8366f2e0>] ? __kthread_create_on_node+0x160/0x160
[    3.922992]  [<83f8d363>] ret_from_fork+0x1b/0x28
[    3.924045] kobject (ff36c36c): tried to init an initialized object, something is seriously wrong.
[    3.926026] CPU: 6 PID: 6 Comm: kworker/u14:0 Not tainted 4.9.0 #86
[    3.927408] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.10.1-1 04/01/2014
[    3.929193] Workqueue: events_unbound async_run_entry_fn
[    3.930404]  80079da8 83a5f6cc ff36c36c be01a5fc 80079dc4 83a61e33 842a883c ff36c36c
[    3.932214]  80079dc4 84397474 be01a108 80079dec 83a46b1c be01a5d8 840670a0 be01a5d8
[    3.934042]  be01a108 bd983468 be01a108 bd983470 be01a5d8 80079e14 83a3c857 be01a5d8
[    3.935857] Call Trace:
[    3.936401]  [<83a5f6cc>] dump_stack+0x58/0x7c
[    3.937382]  [<83a61e33>] kobject_init+0x73/0x80
[    3.938412]  [<83a46b1c>] blk_mq_register_dev+0x4c/0x110
[    3.939579]  [<83a3c857>] blk_register_queue+0x87/0x140
[    3.940731]  [<83a49c7e>] device_add_disk+0x1ce/0x470
[    3.941848]  [<83c3d328>] sd_probe_async+0xe8/0x1b0
[    3.942929]  [<83672347>] async_run_entry_fn+0x37/0xe0
[    3.944063]  [<836694f7>] process_one_work+0x1b7/0x3e0
[    3.945193]  [<8366947c>] ? process_one_work+0x13c/0x3e0
[    3.946371]  [<83669759>] worker_thread+0x39/0x460
[    3.947430]  [<83669720>] ? process_one_work+0x3e0/0x3e0
[    3.948599]  [<8366f394>] kthread+0xb4/0xd0
[    3.949522]  [<83f8cb4d>] ? _raw_spin_unlock_irq+0x2d/0x50
[    3.950733]  [<8366f2e0>] ? __kthread_create_on_node+0x160/0x160
[    3.952053]  [<8366f2e0>] ? __kthread_create_on_node+0x160/0x160
[    3.953372]  [<83f8d363>] ret_from_fork+0x1b/0x28
[    3.954436] kobject (ff4bd36c): tried to init an initialized object, something is seriously wrong.
[    3.956391] CPU: 6 PID: 6 Comm: kworker/u14:0 Not tainted 4.9.0 #86
[    3.957774] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.10.1-1 04/01/2014
[    3.959548] Workqueue: events_unbound async_run_entry_fn
[    3.960737]  80079da8 83a5f6cc ff4bd36c be01a5fc 80079dc4 83a61e33 842a883c ff4bd36c
[    3.962558]  80079dc4 84397474 be01a108 80079dec 83a46b1c be01a5d8 840670a0 be01a5d8
[    3.964369]  be01a108 bd983468 be01a108 bd983470 be01a5d8 80079e14 83a3c857 be01a5d8
[    3.966196] Call Trace:
[    3.966740]  [<83a5f6cc>] dump_stack+0x58/0x7c
[    3.967738]  [<83a61e33>] kobject_init+0x73/0x80
[    3.968754]  [<83a46b1c>] blk_mq_register_dev+0x4c/0x110
[    3.969934]  [<83a3c857>] blk_register_queue+0x87/0x140
[    3.971079]  [<83a49c7e>] device_add_disk+0x1ce/0x470
[    3.972194]  [<83c3d328>] sd_probe_async+0xe8/0x1b0
[    3.973268]  [<83672347>] async_run_entry_fn+0x37/0xe0
[    3.974407]  [<836694f7>] process_one_work+0x1b7/0x3e0
[    3.975531]  [<8366947c>] ? process_one_work+0x13c/0x3e0
[    3.976695]  [<83669759>] worker_thread+0x39/0x460
[    3.977768]  [<83669720>] ? process_one_work+0x3e0/0x3e0
[    3.978932]  [<8366f394>] kthread+0xb4/0xd0
[    3.979844]  [<83f8cb4d>] ? _raw_spin_unlock_irq+0x2d/0x50
[    3.981057]  [<8366f2e0>] ? __kthread_create_on_node+0x160/0x160
[    3.982395]  [<8366f2e0>] ? __kthread_create_on_node+0x160/0x160
[    3.983714]  [<83f8d363>] ret_from_fork+0x1b/0x28
[    3.984762] kobject (ff60e36c): tried to init an initialized object, something is seriously wrong.
[    3.986726] CPU: 6 PID: 6 Comm: kworker/u14:0 Not tainted 4.9.0 #86
[    3.988103] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.10.1-1 04/01/2014
[    3.989879] Workqueue: events_unbound async_run_entry_fn
[    3.991076]  80079da8 83a5f6cc ff60e36c be01a5fc 80079dc4 83a61e33 842a883c ff60e36c
[    3.992896]  80079dc4 84397474 be01a108 80079dec 83a46b1c be01a5d8 840670a0 be01a5d8
[    3.994719]  be01a108 bd983468 be01a108 bd983470 be01a5d8 80079e14 83a3c857 be01a5d8
[    3.996516] Call Trace:
[    3.997057]  [<83a5f6cc>] dump_stack+0x58/0x7c
[    3.998047]  [<83a61e33>] kobject_init+0x73/0x80
[    3.999058]  [<83a46b1c>] blk_mq_register_dev+0x4c/0x110
[    4.000233]  [<83a3c857>] blk_register_queue+0x87/0x140
[    4.001399]  [<83a49c7e>] device_add_disk+0x1ce/0x470
[    4.002516]  [<83c3d328>] sd_probe_async+0xe8/0x1b0
[    4.003578]  [<83672347>] async_run_entry_fn+0x37/0xe0
[    4.004707]  [<836694f7>] process_one_work+0x1b7/0x3e0
[    4.005835]  [<8366947c>] ? process_one_work+0x13c/0x3e0
[    4.006950]  [<83669759>] worker_thread+0x39/0x460
[    4.007965]  [<83669720>] ? process_one_work+0x3e0/0x3e0
[    4.009076]  [<8366f394>] kthread+0xb4/0xd0
[    4.009963]  [<83f8cb4d>] ? _raw_spin_unlock_irq+0x2d/0x50
[    4.011120]  [<8366f2e0>] ? __kthread_create_on_node+0x160/0x160
[    4.012379]  [<8366f2e0>] ? __kthread_create_on_node+0x160/0x160
[    4.013655]  [<83f8d363>] ret_from_fork+0x1b/0x28
[    4.014676] kobject (ff75f36c): tried to init an initialized object, something is seriously wrong.
[    4.016562] CPU: 6 PID: 6 Comm: kworker/u14:0 Not tainted 4.9.0 #86
[    4.017923] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.10.1-1 04/01/2014
[    4.019768] Workqueue: events_unbound async_run_entry_fn
[    4.020980]  80079da8 83a5f6cc ff75f36c be01a5fc 80079dc4 83a61e33 842a883c ff75f36c
[    4.022862]  80079dc4 84397474 be01a108 80079dec 83a46b1c be01a5d8 840670a0 be01a5d8
[    4.024742]  be01a108 bd983468 be01a108 bd983470 be01a5d8 80079e14 83a3c857 be01a5d8
[    4.026624] Call Trace:
[    4.027185]  [<83a5f6cc>] dump_stack+0x58/0x7c
[    4.028181]  [<83a61e33>] kobject_init+0x73/0x80
[    4.029199]  [<83a46b1c>] blk_mq_register_dev+0x4c/0x110
[    4.030390]  [<83a3c857>] blk_register_queue+0x87/0x140
[    4.031550]  [<83a49c7e>] device_add_disk+0x1ce/0x470
[    4.032672]  [<83c3d328>] sd_probe_async+0xe8/0x1b0
[    4.033755]  [<83672347>] async_run_entry_fn+0x37/0xe0
[    4.034895]  [<836694f7>] process_one_work+0x1b7/0x3e0
[    4.036027]  [<8366947c>] ? process_one_work+0x13c/0x3e0
[    4.037197]  [<83669759>] worker_thread+0x39/0x460
[    4.038275]  [<83669720>] ? process_one_work+0x3e0/0x3e0
[    4.039444]  [<8366f394>] kthread+0xb4/0xd0
[    4.040379]  [<83f8cb4d>] ? _raw_spin_unlock_irq+0x2d/0x50
[    4.041625]  [<8366f2e0>] ? __kthread_create_on_node+0x160/0x160
[    4.042951]  [<8366f2e0>] ? __kthread_create_on_node+0x160/0x160
[    4.044271]  [<83f8d363>] ret_from_fork+0x1b/0x28
[    4.045327] kobject (ff8b036c): tried to init an initialized object, something is seriously wrong.
[    4.047323] CPU: 6 PID: 6 Comm: kworker/u14:0 Not tainted 4.9.0 #86
[    4.048707] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.10.1-1 04/01/2014
[    4.050501] Workqueue: events_unbound async_run_entry_fn
[    4.051689]  80079da8 83a5f6cc ff8b036c be01a5fc 80079dc4 83a61e33 842a883c ff8b036c
[    4.053517]  80079dc4 84397474 be01a108 80079dec 83a46b1c be01a5d8 840670a0 be01a5d8
[    4.055352]  be01a108 bd983468 be01a108 bd983470 be01a5d8 80079e14 83a3c857 be01a5d8
[    4.057173] Call Trace:
[    4.057732]  [<83a5f6cc>] dump_stack+0x58/0x7c
[    4.058722]  [<83a61e33>] kobject_init+0x73/0x80
[    4.059738]  [<83a46b1c>] blk_mq_register_dev+0x4c/0x110
[    4.060907]  [<83a3c857>] blk_register_queue+0x87/0x140
[    4.062073]  [<83a49c7e>] device_add_disk+0x1ce/0x470
[    4.063205]  [<83c3d328>] sd_probe_async+0xe8/0x1b0
[    4.064286]  [<83672347>] async_run_entry_fn+0x37/0xe0
[    4.065427]  [<836694f7>] process_one_work+0x1b7/0x3e0
[    4.066569]  [<8366947c>] ? process_one_work+0x13c/0x3e0
[    4.067749]  [<83669759>] worker_thread+0x39/0x460
[    4.068805]  [<83669720>] ? process_one_work+0x3e0/0x3e0
[    4.070001]  [<8366f394>] kthread+0xb4/0xd0
[    4.070946]  [<83f8cb4d>] ? _raw_spin_unlock_irq+0x2d/0x50
[    4.072153]  [<8366f2e0>] ? __kthread_create_on_node+0x160/0x160
[    4.073487]  [<8366f2e0>] ? __kthread_create_on_node+0x160/0x160
[    4.074829]  [<83f8d363>] ret_from_fork+0x1b/0x28
[    4.075943] ------------[ cut here ]------------
[    4.076984] WARNING: CPU: 6 PID: 6 at include/linux/kref.h:46 kobject_get+0x7f/0x90
[    4.079356] CPU: 6 PID: 6 Comm: kworker/u14:0 Not tainted 4.9.0 #86
[    4.080746] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.10.1-1 04/01/2014
[    4.082548] Workqueue: events_unbound async_run_entry_fn
[    4.083731]  80079ce8 83a5f6cc 00000000 84268d0c 80079d18 83654c82 84268e68 00000006
[    4.085551]  00000006 84268d0c 0000002e 83a61ebf 0000002e bd917554 00000000 bd917400
[    4.087383]  80079d2c 83654d41 00000009 00000000 00000000 80079d4c 83a61ebf 3b1c2000
[    4.089206] Call Trace:
[    4.089765]  [<83a5f6cc>] dump_stack+0x58/0x7c
[    4.090772]  [<83654c82>] __warn+0xe2/0x100
[    4.091695]  [<83a61ebf>] ? kobject_get+0x7f/0x90
[    4.092748]  [<83654d41>] warn_slowpath_null+0x21/0x30
[    4.093907]  [<83a61ebf>] kobject_get+0x7f/0x90
[    4.094933]  [<83a624ae>] kobject_add_internal+0x2e/0x2d0
[    4.096131]  [<83713de8>] ? kfree_const+0x18/0x20
[    4.097163]  [<83a61d7b>] ? kobject_set_name_vargs+0x6b/0x90
[    4.098434]  [<83a62785>] kobject_add+0x35/0x80
[    4.099435]  [<83a46951>] blk_mq_register_hctx+0x91/0xb0
[    4.100626]  [<83a46b97>] blk_mq_register_dev+0xc7/0x110
[    4.101819]  [<83a3c857>] blk_register_queue+0x87/0x140
[    4.102963]  [<83a49c7e>] device_add_disk+0x1ce/0x470
[    4.104081]  [<83c3d328>] sd_probe_async+0xe8/0x1b0
[    4.105167]  [<83672347>] async_run_entry_fn+0x37/0xe0
[    4.106309]  [<836694f7>] process_one_work+0x1b7/0x3e0
[    4.107448]  [<8366947c>] ? process_one_work+0x13c/0x3e0
[    4.108629]  [<83669759>] worker_thread+0x39/0x460
[    4.109696]  [<83669720>] ? process_one_work+0x3e0/0x3e0
[    4.110886]  [<8366f394>] kthread+0xb4/0xd0
[    4.111813]  [<83f8cb4d>] ? _raw_spin_unlock_irq+0x2d/0x50
[    4.113022]  [<8366f2e0>] ? __kthread_create_on_node+0x160/0x160
[    4.114360]  [<8366f2e0>] ? __kthread_create_on_node+0x160/0x160
[    4.115688]  [<83f8d363>] ret_from_fork+0x1b/0x28
[    4.117286] ---[ end trace 0425d358b6d5b2f0 ]---
[    4.145499] sd 0:0:0:0: [sda] Attached SCSI disk
[    4.147003] sd 0:0:0:0: [sda] Synchronizing SCSI cache
[    4.177323] scsi host0: scsi_debug: version 1.86 [20160430]
[    4.177323]   dev_size_mb=8, opts=0x0, submit_queues=1, statistics=0
[    4.180742] scsi 0:0:0:0: Direct-Access     Linux    scsi_debug       0186 PQ: 0 ANSI: 7
[    4.254491] sd 0:0:0:0: [sda] 16384 512-byte logical blocks: (8.39 MB/8.00 MiB)
[    4.259480] sd 0:0:0:0: [sda] Write Protect is off
[    4.260536] sd 0:0:0:0: [sda] Mode Sense: 73 00 10 08
[    4.268380] sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, supports DPO and FUA
[    4.311266] Slab corruption (Tainted: G        W      ): kmalloc-32 start=803d3420, len=32
[    4.313051] 000: 73 64 61 00 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a  sda.ZZZZZZZZZZZZ
[    4.314719] 010: 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a a5  ZZZZZZZZZZZZZZZ.
[    4.316351] Prev obj: start=803d3400, len=32
[    4.317265] 000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
[    4.318920] 010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
[    4.320546] Next obj: start=803d3440, len=32
[    4.321482] 000: 72 65 71 75 65 73 74 5f 73 6f 63 6b 5f 54 43 50  request_sock_TCP
[    4.323133] 010: 00 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a a5  .ZZZZZZZZZZZZZZ.
[    4.351856] sd 0:0:0:0: [sda] Attached SCSI disk
[    4.353307] sd 0:0:0:0: [sda] Synchronizing SCSI cache
[    4.355710] Slab corruption (Tainted: G        W      ): kmalloc-32 start=803d36e0, len=32
[    4.357519] 000: 32 35 30 3a 30 00 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a  250:0.ZZZZZZZZZZ
[    4.359148] 010: 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a a5  ZZZZZZZZZZZZZZZ.
[    4.360790] Prev obj: start=803d36c0, len=32
[    4.361390] sd 0:0:0:0: [sda] 16384 512-byte logical blocks: (8.39 MB/8.00 MiB)
[    4.363279] 000: 30 30 3a 30 31 00 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a  00:01.ZZZZZZZZZZ
[    4.364780] sd 0:0:0:0: [sda] Write Protect is off
[    4.364782] sd 0:0:0:0: [sda] Mode Sense: 73 00 10 08
[    4.367051] 010: 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a a5  ZZZZZZZZZZZZZZZ.
[    4.368712] Next obj: start=803d3700, len=32
[    4.369642] 000: 30 3a 30 3a 30 3a 30 00 5a 5a 5a 5a 5a 5a 5a 5a  0:0:0:0.ZZZZZZZZ
[    4.371290] 010: [    4.371499] sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, supports DPO and FUA
[    4.373485] 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a a5  ZZZZZZZZZZZZZZZ.
[    4.377287] Slab corruption (Tainted: G        W      ): kmalloc-32 start=be7f4d80, len=32
[    4.379068] 000: 30 3a 30 3a 30 3a 30 00 5a 5a 5a 5a 5a 5a 5a 5a  0:0:0:0.ZZZZZZZZ
[    4.380719] 010: 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a a5  ZZZZZZZZZZZZZZZ.
[    4.381641] ------------[ cut here ]------------
[    4.381646] WARNING: CPU: 6 PID: 6 at fs/sysfs/dir.c:31 sysfs_warn_dup+0x60/0x80
[    4.381647] sysfs: cannot create duplicate filename '/class/block/sda'
[    4.381649] CPU: 6 PID: 6 Comm: kworker/u14:0 Tainted: G        W       4.9.0 #86
[    4.381650] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.10.1-1 04/01/2014
[    4.381653] Workqueue: events_unbound async_run_entry_fn
[    4.381657]  80079d34 83a5f6cc 80079d78 842785c8 80079d64 83654c82 84278594 80079d94
[    4.381662]  00000006 842785c8 0000001f 837b89e0 0000001f be427000 be7f4040 8027ef80
[    4.381666]  80079d80 83654cd4 00000009 00000000 80079d78 84278594 80079d94 80079da8
[    4.381666] Call Trace:
[    4.381669]  [<83a5f6cc>] dump_stack+0x58/0x7c
[    4.381673]  [<83654c82>] __warn+0xe2/0x100
[    4.381675]  [<837b89e0>] ? sysfs_warn_dup+0x60/0x80
[    4.381676]  [<83654cd4>] warn_slowpath_fmt+0x34/0x40
[    4.381678]  [<837b89e0>] sysfs_warn_dup+0x60/0x80
[    4.381680]  [<837b8cb6>] sysfs_do_create_link_sd.isra.0+0xb6/0xd0
[    4.381682]  [<837b8d10>] sysfs_create_link+0x20/0x40
[    4.381686]  [<83b8469f>] device_add+0x1df/0x5d0
[    4.381688]  [<83713eb8>] ? kstrdup_const+0x18/0x20
[    4.381690]  [<83a6eb49>] ? kvasprintf_const+0x59/0x90
[    4.381692]  [<83713de8>] ? kfree_const+0x18/0x20
[    4.381694]  [<83a61d7b>] ? kobject_set_name_vargs+0x6b/0x90
[    4.381696]  [<83a49c6f>] device_add_disk+0x1bf/0x470
[    4.381699]  [<83b92c06>] ? __pm_runtime_use_autosuspend+0x56/0x70
[    4.381703]  [<83c3d328>] sd_probe_async+0xe8/0x1b0
[    4.381704]  [<83672347>] async_run_entry_fn+0x37/0xe0
[    4.381707]  [<836694f7>] process_one_work+0x1b7/0x3e0
[    4.381708]  [<8366947c>] ? process_one_work+0x13c/0x3e0
[    4.381710]  [<83669759>] worker_thread+0x39/0x460
[    4.381712]  [<83669720>] ? process_one_work+0x3e0/0x3e0
[    4.381713]  [<8366f394>] kthread+0xb4/0xd0
[    4.381716]  [<83f8cb4d>] ? _raw_spin_unlock_irq+0x2d/0x50
[    4.381718]  [<8366f2e0>] ? __kthread_create_on_node+0x160/0x160
[    4.381719]  [<8366f2e0>] ? __kthread_create_on_node+0x160/0x160
[    4.381721]  [<83f8d363>] ret_from_fork+0x1b/0x28
[    4.381722] ---[ end trace 0425d358b6d5b2f1 ]---
[    4.381738] ------------[ cut here ]------------
[    4.381740] WARNING: CPU: 6 PID: 6 at lib/kobject.c:244 kobject_add_internal+0xf0/0x2d0
[    4.381741] kobject_add_internal failed for queue (error: -2 parent: sda)
[    4.381742] CPU: 6 PID: 6 Comm: kworker/u14:0 Tainted: G        W       4.9.0 #86
[    4.381743] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.10.1-1 04/01/2014
[    4.381745] Workqueue: events_unbound async_run_entry_fn
[    4.381749]  80079d4c 83a5f6cc 80079d90 842a88e0 80079d7c 83654c82 842a8a40 80079dac
[    4.381753]  00000006 842a88e0 000000f4 83a62570 000000f4 be01ade0 00000000 bd983870
[    4.381757]  80079d98 83654cd4 00000009 00000000 80079d90 842a8a40 80079dac 80079dd0
[    4.381758] Call Trace:
[    4.381760]  [<83a5f6cc>] dump_stack+0x58/0x7c
[    4.381761]  [<83654c82>] __warn+0xe2/0x100
[    4.381763]  [<83a62570>] ? kobject_add_internal+0xf0/0x2d0
[    4.381765]  [<83654cd4>] warn_slowpath_fmt+0x34/0x40
[    4.381767]  [<83a62570>] kobject_add_internal+0xf0/0x2d0
[    4.381768]  [<83a62785>] kobject_add+0x35/0x80
[    4.381770]  [<83713eb8>] ? kstrdup_const+0x18/0x20
[    4.381773]  [<83a3c834>] blk_register_queue+0x64/0x140
[    4.381775]  [<83a49c7e>] device_add_disk+0x1ce/0x470
[    4.381777]  [<83b92c06>] ? __pm_runtime_use_autosuspend+0x56/0x70
[    4.381779]  [<83c3d328>] sd_probe_async+0xe8/0x1b0
[    4.381780]  [<83672347>] async_run_entry_fn+0x37/0xe0
[    4.381782]  [<836694f7>] process_one_work+0x1b7/0x3e0
[    4.381784]  [<8366947c>] ? process_one_work+0x13c/0x3e0
[    4.381785]  [<83669759>] worker_thread+0x39/0x460
[    4.381787]  [<83669720>] ? process_one_work+0x3e0/0x3e0
[    4.381788]  [<8366f394>] kthread+0xb4/0xd0
[    4.381790]  [<83f8cb4d>] ? _raw_spin_unlock_irq+0x2d/0x50
[    4.381792]  [<8366f2e0>] ? __kthread_create_on_node+0x160/0x160
[    4.381793]  [<8366f2e0>] ? __kthread_create_on_node+0x160/0x160
[    4.381795]  [<83f8d363>] ret_from_fork+0x1b/0x28
[    4.381795] ---[ end trace 0425d358b6d5b2f2 ]---
[    4.381796] ------------[ cut here ]------------
[    4.381798] WARNING: CPU: 6 PID: 6 at block/genhd.c:632 device_add_disk+0x3ef/0x470
[    4.381800] CPU: 6 PID: 6 Comm: kworker/u14:0 Tainted: G        W       4.9.0 #86
[    4.381800] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.10.1-1 04/01/2014
[    4.381802] Workqueue: events_unbound async_run_entry_fn
[    4.381806]  80079dd0 83a5f6cc 00000000 842a6920 80079e00 83654c82 84268e68 00000006
[    4.381810]  00000006 842a6920 00000278 83a49e9f 00000278 bd983800 bd983868 bd983870
[    4.381814]  80079e14 83654d41 00000009 00000000 00000000 80079e54 83a49e9f bd983868
[    4.381814] Call Trace:
[    4.381816]  [<83a5f6cc>] dump_stack+0x58/0x7c
[    4.381818]  [<83654c82>] __warn+0xe2/0x100
[    4.381819]  [<83a49e9f>] ? device_add_disk+0x3ef/0x470
[    4.381821]  [<83654d41>] warn_slowpath_null+0x21/0x30
[    4.381823]  [<83a49e9f>] device_add_disk+0x3ef/0x470
[    4.381825]  [<83b92c06>] ? __pm_runtime_use_autosuspend+0x56/0x70
[    4.381827]  [<83c3d328>] sd_probe_async+0xe8/0x1b0
[    4.381828]  [<83672347>] async_run_entry_fn+0x37/0xe0
[    4.381830]  [<836694f7>] process_one_work+0x1b7/0x3e0
[    4.381831]  [<8366947c>] ? process_one_work+0x13c/0x3e0
[    4.381833]  [<83669759>] worker_thread+0x39/0x460
[    4.381835]  [<83669720>] ? process_one_work+0x3e0/0x3e0
[    4.381836]  [<8366f394>] kthread+0xb4/0xd0
[    4.381838]  [<83f8cb4d>] ? _raw_spin_unlock_irq+0x2d/0x50
[    4.381839]  [<8366f2e0>] ? __kthread_create_on_node+0x160/0x160
[    4.381841]  [<8366f2e0>] ? __kthread_create_on_node+0x160/0x160
[    4.381842]  [<83f8d363>] ret_from_fork+0x1b/0x28
[    4.381843] ---[ end trace 0425d358b6d5b2f3 ]---
[    4.381851] ------------[ cut here ]------------
[    4.381852] kernel BUG at fs/sysfs/file.c:330!
[    4.381853] invalid opcode: 0000 [#1] PREEMPT SMP
[    4.381854] CPU: 6 PID: 6 Comm: kworker/u14:0 Tainted: G        W       4.9.0 #86
[    4.381855] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.10.1-1 04/01/2014
[    4.381856] Workqueue: events_unbound async_run_entry_fn
[    4.381857] task: 80076300 task.stack: 80078000
[    4.381858] EIP: 0060:[<837b86b0>] EFLAGS: 00210246 CPU: 6
[    4.381860] EIP is at sysfs_create_file_ns+0x30/0x40
[    4.381861] EAX: 00000000 EBX: 00000000 ECX: 00000000 EDX: 84026764
[    4.381862] ESI: bd983870 EDI: 84397640 EBP: 80079e14 ESP: 80079dfc
[    4.381863]  DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
[    4.381864] CR0: 80050033 CR2: ffffffff CR3: 04617000 CR4: 000006b0
[    4.381867] Stack:
[    4.381871]  837b87cf 80079e14 bd983870 bd983800 bd983868 bd983870 80079e54 83a49cc7
[    4.381874]  bd983868 8429adcd bd98380c bd983800 be01a910 bd98380c 00800000 83b92c06
[    4.381878]  be01a910 bd925800 bd983800 be429400 bd925800 bd983800 80079e80 83c3d328
[    4.381878] Call Trace:
[    4.381880]  [<837b87cf>] ? sysfs_create_files+0x2f/0x90
[    4.381882]  [<83a49cc7>] device_add_disk+0x217/0x470
[    4.381884]  [<83b92c06>] ? __pm_runtime_use_autosuspend+0x56/0x70
[    4.381885]  [<83c3d328>] sd_probe_async+0xe8/0x1b0
[    4.381887]  [<83672347>] async_run_entry_fn+0x37/0xe0
[    4.381888]  [<836694f7>] process_one_work+0x1b7/0x3e0
[    4.381890]  [<8366947c>] ? process_one_work+0x13c/0x3e0
[    4.381891]  [<83669759>] worker_thread+0x39/0x460
[    4.381893]  [<83669720>] ? process_one_work+0x3e0/0x3e0
[    4.381894]  [<8366f394>] kthread+0xb4/0xd0
[    4.381896]  [<83f8cb4d>] ? _raw_spin_unlock_irq+0x2d/0x50
[    4.381897]  [<8366f2e0>] ? __kthread_create_on_node+0x160/0x160
[    4.381898]  [<8366f2e0>] ? __kthread_create_on_node+0x160/0x160
[    4.381900]  [<83f8d363>] ret_from_fork+0x1b/0x28
[    4.381921] Code: 40 18 85 c0 74 25 85 d2 74 21 55 89 e5 83 ec 08 89 4c 24 04 0f b7 4a 04 89 0c 24 31 c9 e8 99 fd ff ff c9 c3 8d b4 26 00 00 00 00 <0f> 0b 8d b4 26 00 00 00 00 8d bc 27 00 00 00 00 55 89 e5 56 89
[    4.381923] EIP: [<837b86b0>] 
[    4.381924] sysfs_create_file_ns+0x30/0x40
[    4.381924]  SS:ESP 0068:80079dfc
[    4.381928] ---[ end trace 0425d358b6d5b2f4 ]---
[    4.381929] Kernel panic - not syncing: Fatal exception
[    4.382334] Kernel Offset: 0x2600000 from 0x81000000 (relocation range: 0x80000000-0xc07d4fff)
[    4.439732] ---[ end Kernel panic - not syncing: Fatal exception

> > yes. With and without the patch there is a lot of wrong stuff like
> > complains about a kobject initialized again. This leads to a double free
> > at some point.
> 
> And what patch are we talking about? I don't mind being CC'ed into a thread,
> but some context and background would be immensely helpful here...

The patch is irrelevant. lkp-robot found a bug which was there before
the patch in question but the pattern changed so it blamed the Author.
It triggers even v4.9 with
  CONFIG_SCSI_DEBUG
  CONFIG_DEBUG_TEST_DRIVER_REMOVE
  CONFIG_SCSI_MQ_DEFAULT
enabled and CONFIG_SCSI_DEBUG is simply a SCSI host controller which is
always there. I can send you a complete config against current HEAD
which boots in kvm if you want.

Sebastian

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [lkp-robot] [rcu] b332151a29: kernel_BUG_at_mm/slab.c
  2017-01-20 16:23     ` Sebastian Andrzej Siewior
@ 2017-01-20 16:32       ` Jens Axboe
  2017-01-20 17:09         ` Sebastian Andrzej Siewior
  0 siblings, 1 reply; 6+ messages in thread
From: Jens Axboe @ 2017-01-20 16:32 UTC (permalink / raw)
  To: Sebastian Andrzej Siewior
  Cc: kernel test robot, Paul E. McKenney, LKML, lkp, linux-scsi, tglx,
	linux-block

On 01/20/2017 08:23 AM, Sebastian Andrzej Siewior wrote:
>>> yes. With and without the patch there is a lot of wrong stuff like
>>> complains about a kobject initialized again. This leads to a double free
>>> at some point.
>>
>> And what patch are we talking about? I don't mind being CC'ed into a thread,
>> but some context and background would be immensely helpful here...
> 
> The patch is irrelevant. lkp-robot found a bug which was there before
> the patch in question but the pattern changed so it blamed the Author.
> It triggers even v4.9 with
>   CONFIG_SCSI_DEBUG
>   CONFIG_DEBUG_TEST_DRIVER_REMOVE
>   CONFIG_SCSI_MQ_DEFAULT
> enabled and CONFIG_SCSI_DEBUG is simply a SCSI host controller which is
> always there. I can send you a complete config against current HEAD
> which boots in kvm if you want.

That's alright, sounds like it's not a -next regression, but rather something
that is already broken. I can reproduce a lot of breakage if I enable
CONFIG_DEBUG_TEST_DRIVER_REMOVE, in fact my system doesn't boot at all. This
is the first bug:

[   18.247895] ------------[ cut here ]------------
[   18.247907] WARNING: CPU: 21 PID: 2223 at drivers/ata/libata-core.c:6522 ata_host_detach+0x11b]
[   18.247908] Modules linked in: igb(+) ahci(+) libahci i2c_algo_bit dca libata nvme(+) nvme_core
[   18.247917] CPU: 21 PID: 2223 Comm: systemd-udevd Tainted: G        W       4.10.0-rc4+ #30
[   18.247919] Hardware name: Dell Inc. PowerEdge T630/0NT78X, BIOS 2.3.4 11/09/2016
[   18.247919] Call Trace:
[   18.247928]  dump_stack+0x68/0x93
[   18.247934]  __warn+0xc6/0xe0
[   18.247937]  warn_slowpath_null+0x18/0x20
[   18.247943]  ata_host_detach+0x11b/0x120 [libata]
[   18.247950]  ata_pci_remove_one+0x10/0x20 [libata]
[   18.247955]  ahci_remove_one+0x10/0x20 [ahci]
[   18.247958]  pci_device_remove+0x34/0xb0
[   18.247966]  driver_probe_device+0xd0/0x370
[   18.247969]  __driver_attach+0x9a/0xa0
[   18.247971]  ? driver_probe_device+0x370/0x370
[   18.247973]  bus_for_each_dev+0x5d/0x90
[   18.247975]  driver_attach+0x19/0x20
[   18.247977]  bus_add_driver+0x11f/0x220
[   18.247980]  driver_register+0x5b/0xd0
[   18.247982]  __pci_register_driver+0x58/0x60
[   18.247984]  ? 0xffffffffa00d9000
[   18.247988]  ahci_pci_driver_init+0x1e/0x20 [ahci]
[   18.247992]  do_one_initcall+0x3e/0x170
[   18.247997]  ? rcu_read_lock_sched_held+0x45/0x80
[   18.248001]  ? kmem_cache_alloc_trace+0x22e/0x290
[   18.248004]  do_init_module+0x5a/0x1cb
[   18.248007]  load_module+0x1e60/0x2570
[   18.248008]  ? __symbol_put+0x70/0x70
[   18.248010]  ? show_coresize+0x30/0x30
[   18.248013]  ? kernel_read_file+0x19e/0x1c0
[   18.248015]  ? kernel_read_file_from_fd+0x44/0x70
[   18.248016]  SYSC_finit_module+0xba/0xc0
[   18.248018]  SyS_finit_module+0x9/0x10
[   18.248021]  entry_SYSCALL_64_fastpath+0x18/0xad
[   18.248022] RIP: 0033:0x7f49c5a645b9
[   18.248023] RSP: 002b:00007ffccf512658 EFLAGS: 00000246 ORIG_RAX: 0000000000000139
[   18.248025] RAX: ffffffffffffffda RBX: 00007f49c61659dd RCX: 00007f49c5a645b9
[   18.248026] RDX: 0000000000000000 RSI: 00007f49c53152c7 RDI: 0000000000000009
[   18.248026] RBP: 0000000000020000 R08: 0000000000000000 R09: 0000000000000000
[   18.248027] R10: 0000000000000009 R11: 0000000000000246 R12: 0000555737e82b30
[   18.248028] R13: 0000555737e71200 R14: 0000555737e82b30 R15: 0000000000000000
[   18.248030] ---[ end trace b0ae5eae3430d5d6 ]---

and it's even more downhill from there. That option is marked unstable, are we
expecting it to work right now?

-- 
Jens Axboe

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [lkp-robot] [rcu] b332151a29: kernel_BUG_at_mm/slab.c
  2017-01-20 16:32       ` Jens Axboe
@ 2017-01-20 17:09         ` Sebastian Andrzej Siewior
  2017-01-20 17:15           ` Jens Axboe
  0 siblings, 1 reply; 6+ messages in thread
From: Sebastian Andrzej Siewior @ 2017-01-20 17:09 UTC (permalink / raw)
  To: Jens Axboe
  Cc: kernel test robot, Paul E. McKenney, LKML, lkp, linux-scsi, tglx,
	linux-block

On 2017-01-20 08:32:37 [-0800], Jens Axboe wrote:
> That's alright, sounds like it's not a -next regression, but rather somet=
hing
> that is already broken. I can reproduce a lot of breakage if I enable
> CONFIG_DEBUG_TEST_DRIVER_REMOVE, in fact my system doesn't boot at all. T=
his
> is the first bug:
>=20
> [   18.247895] ------------[ cut here ]------------
> [   18.247907] WARNING: CPU: 21 PID: 2223 at drivers/ata/libata-core.c:65=
22 ata_host_detach+0x11b]
> [   18.247908] Modules linked in: igb(+) ahci(+) libahci i2c_algo_bit dca=
 libata nvme(+) nvme_core
> [   18.247917] CPU: 21 PID: 2223 Comm: systemd-udevd Tainted: G        W =
      4.10.0-rc4+ #30
> [   18.247919] Hardware name: Dell Inc. PowerEdge T630/0NT78X, BIOS 2.3.4=
 11/09/2016
> [   18.247919] Call Trace:
> [   18.247928]  dump_stack+0x68/0x93
> [   18.247934]  __warn+0xc6/0xe0
> [   18.247937]  warn_slowpath_null+0x18/0x20
> [   18.247943]  ata_host_detach+0x11b/0x120 [libata]
=E2=80=A6

> and it's even more downhill from there. That option is marked unstable, a=
re we
> expecting it to work right now?

Well, as per 248ff0216543 ("driver core: Make Kconfig text for
DEBUG_TEST_DRIVER_REMOVE stronger"):

|   The current state of driver removal is not great.
|   CONFIG_DEBUG_TEST_DRIVER_REMOVE finds lots of errors. The help text
|   currently undersells exactly how many errors this option will find. Add
|   a bit more description to indicate this option shouldn't be turned on
|   unless you actually want to debug driver removal. The text can be
|   changed later when more drivers are fixed up.

so it looks like the option is working but it uncovers bugs. I've put
you in TO because the breakage in kvm test went away after I disabled
the MQ support in SCSI. So I *assumed* that MQ was not doing something
right in the removal path. I don't know if this libata-core backtrace is
a false positive or not.

Sebastian

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [lkp-robot] [rcu] b332151a29: kernel_BUG_at_mm/slab.c
  2017-01-20 17:09         ` Sebastian Andrzej Siewior
@ 2017-01-20 17:15           ` Jens Axboe
  0 siblings, 0 replies; 6+ messages in thread
From: Jens Axboe @ 2017-01-20 17:15 UTC (permalink / raw)
  To: Sebastian Andrzej Siewior
  Cc: kernel test robot, Paul E. McKenney, LKML, lkp, linux-scsi, tglx,
	linux-block

On 01/20/2017 09:09 AM, Sebastian Andrzej Siewior wrote:
> On 2017-01-20 08:32:37 [-0800], Jens Axboe wrote:
>> That's alright, sounds like it's not a -next regression, but rather something
>> that is already broken. I can reproduce a lot of breakage if I enable
>> CONFIG_DEBUG_TEST_DRIVER_REMOVE, in fact my system doesn't boot at all. This
>> is the first bug:
>>
>> [   18.247895] ------------[ cut here ]------------
>> [   18.247907] WARNING: CPU: 21 PID: 2223 at drivers/ata/libata-core.c:6522 ata_host_detach+0x11b]
>> [   18.247908] Modules linked in: igb(+) ahci(+) libahci i2c_algo_bit dca libata nvme(+) nvme_core
>> [   18.247917] CPU: 21 PID: 2223 Comm: systemd-udevd Tainted: G        W       4.10.0-rc4+ #30
>> [   18.247919] Hardware name: Dell Inc. PowerEdge T630/0NT78X, BIOS 2.3.4 11/09/2016
>> [   18.247919] Call Trace:
>> [   18.247928]  dump_stack+0x68/0x93
>> [   18.247934]  __warn+0xc6/0xe0
>> [   18.247937]  warn_slowpath_null+0x18/0x20
>> [   18.247943]  ata_host_detach+0x11b/0x120 [libata]
> …
> 
>> and it's even more downhill from there. That option is marked unstable, are we
>> expecting it to work right now?
> 
> Well, as per 248ff0216543 ("driver core: Make Kconfig text for
> DEBUG_TEST_DRIVER_REMOVE stronger"):
> 
> |   The current state of driver removal is not great.
> |   CONFIG_DEBUG_TEST_DRIVER_REMOVE finds lots of errors. The help text
> |   currently undersells exactly how many errors this option will find. Add
> |   a bit more description to indicate this option shouldn't be turned on
> |   unless you actually want to debug driver removal. The text can be
> |   changed later when more drivers are fixed up.
> 
> so it looks like the option is working but it uncovers bugs. I've put
> you in TO because the breakage in kvm test went away after I disabled
> the MQ support in SCSI. So I *assumed* that MQ was not doing something
> right in the removal path. I don't know if this libata-core backtrace is
> a false positive or not.

Sure, I get that, my question is just if it's always finding valid bugs,
or if the test itself is buggy. The fact that I can't boot anything after
enabling it makes me suspicious.

Or maybe the state of load/remove/load is just pretty sad.

-- 
Jens Axboe

^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2017-01-20 17:15 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
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2017-01-20 16:01 ` [lkp-robot] [rcu] b332151a29: kernel_BUG_at_mm/slab.c Sebastian Andrzej Siewior
2017-01-20 16:09   ` Jens Axboe
2017-01-20 16:23     ` Sebastian Andrzej Siewior
2017-01-20 16:32       ` Jens Axboe
2017-01-20 17:09         ` Sebastian Andrzej Siewior
2017-01-20 17:15           ` Jens Axboe

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