Messages in this thread | | | Subject | Re: get/put_cpu() usage in block/blk-mq.c | From | Jens Axboe <> | Date | Tue, 9 May 2017 09:45:41 -0600 |
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On 05/09/2017 09:40 AM, Mike Galbraith wrote: > On Tue, 2017-05-09 at 09:15 -0600, Jens Axboe wrote: >> On 05/09/2017 09:13 AM, Jens Axboe wrote: >>> On 05/09/2017 09:04 AM, Mike Galbraith wrote: >>>> On Tue, 2017-05-09 at 08:53 -0600, Jens Axboe wrote: >>>>> On 05/09/2017 12:07 AM, Mike Galbraith wrote: >>>>>> Hi Jens, >>>>>> >>>>>> I was about to fix up this splat.. >>>>>> >>>>>> [ 445.022141] loop: module loaded >>>>>> [ 445.078116] BUG: using smp_processor_id() in preemptible >>>>>> [00000000] code: loop0/3801 >>>>>> [ 445.085873] caller is debug_smp_processor_id+0x17/0x20 >>>>>> [ 445.091016] CPU: 7 PID: 3801 Comm: loop0 Tainted: G >>>>>> E 4.12.0-default #40 >>>>>> [ 445.098838] Hardware name: IBM System x3550 M3 -[7944K3G] >>>>>> -/69Y5698 , BIOS -[D6E150AUS-1.10]- 12/15/2010 >>>>>> [ 445.108564] Call Trace: >>>>>> [ 445.111016] dump_stack+0x65/0x89 >>>>>> [ 445.114330] check_preemption_disabled+0xde/0xf0 >>>>>> [ 445.118945] debug_smp_processor_id+0x17/0x20 >>>>>> [ 445.123300] blk_stat_add+0xb0/0x130 >>>>>> [ 445.126876] __blk_mq_complete_request+0xb5/0x150 >>>>>> [ 445.131575] blk_mq_complete_request+0x16/0x20 >>>>>> [ 445.136020] loop_queue_work+0x5f/0xaa0 [loop] >>>>>> [ 445.140461] ? _raw_spin_unlock_irq+0x21/0x40 >>>>>> [ 445.144816] ? finish_task_switch+0x85/0x270 >>>>>> [ 445.149085] ? __schedule+0x291/0x8c0 >>>>>> [ 445.152747] kthread_worker_fn+0xc2/0x1d0 >>>>>> [ 445.156754] kthread+0x114/0x150 >>>>>> [ 445.159983] ? __kthread_init_worker+0xb0/0xb0 >>>>>> [ 445.164424] ? kthread_park+0x60/0x60 >>>>>> [ 445.168085] ret_from_fork+0x2c/0x40 >>>>> >>>>> Is it from this_cpu_ptr() in blk_stat_add()? >>>> >>>> Yeah. >>> >>> So why is this complaining, doesn't rcu_read_lock() disable >>> preemption? >> >> Ah, I guess it doesn't if PREEMPT_RCU is set. How about the below? > > Should do it. I was about to run LTP (where it turned up) again > anyway, I'll add this. No news is good news, what you should hear.
Thanks, let me know, so I can add your tested-by (or whatever you prefer).
-- Jens Axboe
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