On Mon, 2013-12-23 at 11:16 +0800, Fengguang Wu wrote:
> Greetings,
>
> I got the below dmesg and the first bad commit is
>
> commit 29ff818720ce09b044652b83e9c70ef474800d54
> Author: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
> AuthorDate: Thu May 23 22:11:38 2013 -0700
> Commit: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
> CommitDate: Sun Dec 22 13:00:48 2013 +0000
>
> scsi-debug: Enable scsi-mq operation
>
> v4 changes:
> - Bump can_queue to 64 for performance testing
> - Enable scsi-mq DIF support
> - Add nop_fs_io module parameter for performance testing
>
> Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
>
> +-----------------------------------------------------+----+
> | | |
> +-----------------------------------------------------+----+
> | boot_successes | 0 |
> | boot_failures | 19 |
> | WARNING:CPU:PID:at_block/elevator.c:elevator_init() | 19 |
> +-----------------------------------------------------+----+
>
> [ 4.763205] CPU 1 -> Queue 0
> [ 4.764566] ------------[ cut here ]------------
> [ 4.764566] ------------[ cut here ]------------
> [ 4.765951] WARNING: CPU: 0 PID: 99 at block/elevator.c:193 elevator_init+0xf0/0xfb()
>
> Attached are the full dmesg and kconfig.
>
Mmm, so elevator_init() is now expecting q->sysfs_lock to be held after:
commit eb1c160b22655fd4ec44be732d6594fd1b1e44f4
Author: Tomoki Sekiyama <tomoki.sekiyama@xxxxxxx>
Date: Tue Oct 15 16:42:16 2013 -0600
elevator: Fix a race in elevator switching and md device initialization
Adding the following scsi_mq_alloc_queue() patch to quiet this warning.
Thanks Fengguang!
--nab
diff --git a/drivers/scsi/scsi-mq.c b/drivers/scsi/scsi-mq.c
index dad720a..188509d 100644
--- a/drivers/scsi/scsi-mq.c
+++ b/drivers/scsi/scsi-mq.c
@@ -151,7 +151,7 @@ int scsi_mq_alloc_queue(struct Scsi_Host *sh, struct scsi_device *sdev)
struct request_queue *q;
struct request *rq;
struct scsi_cmnd *sc;
- int i, j, sgl_size;
+ int i, j, rc, sgl_size;
bool prot = true;
sdev->sdev_mq_reg.ops = &scsi_mq_ops;
@@ -181,8 +181,11 @@ int scsi_mq_alloc_queue(struct Scsi_Host *sh, struct scsi_device *sdev)
q->sg_reserved_size = INT_MAX;
- if (elevator_init(q, NULL)) {
- dump_stack();
+ mutex_lock(&q->sysfs_lock);
+ rc = elevator_init(q, NULL);
+ mutex_unlock(&q->sysfs_lock);
+ if (rc) {
+ pr_err("elevator_init failed for scsi-mq: %d\n", rc);
return -ENOMEM;
}
/*
--
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