On 22 March 2018 at 10:31, Adrian Hunter <adrian.hunter@xxxxxxxxx> wrote:
> On 22/03/18 10:43, Shawn Lin wrote:
>> On 2018/3/22 16:26, Adrian Hunter wrote:
>>> On 22/03/18 09:49, Shawn Lin wrote:
>>>> dd if=/dev/urandom of=/dev/mmcblk1 bs=4k count=10000
>>>> with a SD card hotplug during transfer reports a warning below:
>>>
>>> What kernel version / commit was it?
>>
>> Actually the log below has it, it is clean : 4.16.0-rc6-next-20180321
>
> Ok so it seems to be coming from this patch in next:
>
> commit a063057d7c731cffa7d10740e8ebc2970df8dbb3
> Author: Bart Van Assche <bart.vanassche@xxxxxxx>
> Date: Wed Feb 28 10:15:33 2018 -0800
>
> block: Fix a race between request queue removal and the block cgroup controller
>
> Avoid that the following race can occur:
>
> blk_cleanup_queue() blkcg_print_blkgs()
> spin_lock_irq(lock) (1) spin_lock_irq(blkg->q->queue_lock) (2,5)
> q->queue_lock = &q->__queue_lock (3)
> spin_unlock_irq(lock) (4)
> spin_unlock_irq(blkg->q->queue_lock) (6)
>
> (1) take driver lock;
> (2) busy loop for driver lock;
> (3) override driver lock with internal lock;
> (4) unlock driver lock;
> (5) can take driver lock now;
> (6) but unlock internal lock.
>
> This change is safe because only the SCSI core and the NVME core keep
> a reference on a request queue after having called blk_cleanup_queue().
> Neither driver accesses any of the removed data structures between its
> blk_cleanup_queue() and blk_put_queue() calls.
>
> Reported-by: Joseph Qi <joseph.qi@xxxxxxxxxxxxxxxxx>
> Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxx>
> Reviewed-by: Joseph Qi <joseph.qi@xxxxxxxxxxxxxxxxx>
> Cc: Jan Kara <jack@xxxxxxxx>
> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Looks like a reasonable analyze!
Shawn, could you please re-post your patch to linux-block, Jens,
cc:mmc-list, me and Adrian.
I think the patch should be picked up by Jens and go via his tree.
Kind regards
Uffe
>
>
>>
>>>
>>>>
>>>> Remove the disk, partition and bdi sysfs attributes before cleaning
>>>> up the request queue associated with the disk.
>>>>
>>>> [ 410.331226] mmc1: card 59b4 removed
>>>> [ 410.348583] WARNING: CPU: 0 PID: 5 at block/blk-core.c:785
>>>> blk_cleanup_queue+0x138/0x140
>>>> [ 410.349294] Modules linked in:
>>>> [ 410.349570] CPU: 0 PID: 5 Comm: kworker/0:0 Not tainted
>>>> 4.16.0-rc6-next-20180321-00004-gc2ad6a7 #263
>>>> [ 410.350363] Hardware name: Excavator-RK3399 Board (DT)
>>>> [ 410.350819] Workqueue: events_freezable mmc_rescan
>>>> [ 410.351242] pstate: 60000005 (nZCv daif -PAN -UAO)
>>>> [ 410.351663] pc : blk_cleanup_queue+0x138/0x140
>>>> [ 410.352054] lr : blk_cleanup_queue+0xac/0x140
>>>> [ 410.352436] sp : ffff0000092cbb90
>>>> [ 410.352727] x29: ffff0000092cbb90 x28: 0000000000000000
>>>> [ 410.353195] x27: ffff8000f6f23030 x26: ffff00000904e610
>>>> [ 410.353662] x25: ffff8000f17cc808 x24: ffff8000f1038200
>>>> [ 410.354128] x23: 0000000000000060 x22: 0000000000000000
>>>> [ 410.354595] x21: ffff8000f11748d8 x20: ffff8000f1038200
>>>> [ 410.355061] x19: ffff8000f1174200 x18: 0000ffff936347d8
>>>> [ 410.355528] x17: 0000ffff935b93c0 x16: ffff0000081263f8
>>>> [ 410.355994] x15: 0000000000000000 x14: 0000000000000400
>>>> [ 410.356461] x13: 0000000000000001 x12: 0000000000000001
>>>> [ 410.356927] x11: 0000000000000040 x10: ffff8000f2400028
>>>> [ 410.357393] x9 : ffff8000f2400040 x8 : 0000000000000000
>>>> [ 410.357860] x7 : ffff8000f6f3a340 x6 : ffff8000f6f3a340
>>>> [ 410.358326] x5 : ffff8000f2400000 x4 : ffff8000f6f3a340
>>>> [ 410.358792] x3 : 0000000000000000 x2 : 39c1333e45670800
>>>> [ 410.359259] x1 : 0000000000000000 x0 : 0000000000000003
>>>> [ 410.359726] Call trace:
>>>> [ 410.359943] blk_cleanup_queue+0x138/0x140
>>>> [ 410.360305] mmc_cleanup_queue+0x2c/0x48
>>>> [ 410.360652] mmc_blk_remove_req+0x1c/0x98
>>>> [ 410.361005] mmc_blk_remove+0x180/0x1c0
>>>> [ 410.361343] mmc_bus_remove+0x1c/0x28
>>>> [ 410.361670] device_release_driver_internal+0x154/0x1f0
>>>> [ 410.362128] device_release_driver+0x14/0x20
>>>> [ 410.362504] bus_remove_device+0xc8/0x108
>>>> [ 410.362858] device_del+0x120/0x350
>>>> [ 410.363167] mmc_remove_card+0x5c/0xb8
>>>> [ 410.363498] mmc_sd_detect+0x40/0x78
>>>> [ 410.363813] mmc_rescan+0x19c/0x368
>>>> [ 410.364123] process_one_work+0x1ac/0x318
>>>> [ 410.364477] worker_thread+0x50/0x450
>>>> [ 410.364801] kthread+0xf8/0x128
>>>> [ 410.365081] ret_from_fork+0x10/0x18
>>>> [ 410.365395] ---[ end trace 268e87a46c28968c ]---
>>>>
>>>> Signed-off-by: Shawn Lin <shawn.lin@xxxxxxxxxxxxxx>
>>>> ---
>>>>
>>>> drivers/mmc/core/block.c | 2 +-
>>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>>
>>>> diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
>>>> index a2b9c25..02485e3 100644
>>>> --- a/drivers/mmc/core/block.c
>>>> +++ b/drivers/mmc/core/block.c
>>>> @@ -2659,7 +2659,6 @@ static void mmc_blk_remove_req(struct mmc_blk_data
>>>> *md)
>>>> * from being accepted.
>>>> */
>>>> card = md->queue.card;
>>>> - mmc_cleanup_queue(&md->queue);
>>>> if (md->disk->flags & GENHD_FL_UP) {
>>>> device_remove_file(disk_to_dev(md->disk), &md->force_ro);
>>>> if ((md->area_type & MMC_BLK_DATA_AREA_BOOT) &&
>>>> @@ -2669,6 +2668,7 @@ static void mmc_blk_remove_req(struct mmc_blk_data
>>>> *md)
>>>> del_gendisk(md->disk);
>>>> }
>>>> + mmc_cleanup_queue(&md->queue);
>>>> mmc_blk_put(md);
>>>> }
>>>> }
>>>>
>>>
>>>
>>>
>>>
>>
>>
>
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