Re: Boot regression (was "Re: [PATCH] genhd: Do not hold event lock when scheduling workqueue elements")

From: "hch@lst.de" <hch@lst.de>
To: Dexuan Cui <decui@microsoft.com>
Cc: "hch@lst.de" <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
	Bart Van Assche <Bart.VanAssche@sandisk.com>,
	"hare@suse.com" <hare@suse.com>, "hare@suse.de" <hare@suse.de>,
	"Martin K. Petersen" <martin.petersen@oracle.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
	"jth@kernel.org" <jth@kernel.org>,
	Nick Meier <Nick.Meier@microsoft.com>,
	"Alex Ng (LIS)" <alexng@microsoft.com>,
	Long Li <longli@microsoft.com>,
	"Adrian Suhov (Cloudbase Solutions SRL)" <v-adsuho@microsoft.com>,
	"Chris Valean (Cloudbase Solutions SRL)" <v-chvale@microsoft.com>
Subject: Re: Boot regression (was "Re: [PATCH] genhd: Do not hold event lock when scheduling workqueue elements")
Date: Tue, 14 Feb 2017 14:47:36 +0100	[thread overview]
Message-ID: <20170214134736.GA19620@lst.de> (raw)
In-Reply-To: <MWHPR03MB2669B4FFC900983C8C357A77BF440@MWHPR03MB2669.namprd03.prod.outlook.com>

Hi Dexuan,

can you try the hack below for now?  I disable the TUR call from
sd_check_events, which I think your VM is hanging on.  The checks
it does on the sense data look a bit fishy, but so far I've not
identified a possible root cause.

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 40b4038c019e..1502e87c2be9 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -1457,9 +1457,13 @@ static unsigned int sd_check_events(struct gendisk *disk, unsigned int clearing)
 	retval = -ENODEV;
 
 	if (scsi_block_when_processing_errors(sdp)) {
+#if 0
 		sshdr  = kzalloc(sizeof(*sshdr), GFP_KERNEL);
 		retval = scsi_test_unit_ready(sdp, SD_TIMEOUT, SD_MAX_RETRIES,
 					      sshdr);
+#else
+		retval = 0;
+#endif
 	}
 
 	/* failed to execute TUR, assume media not present */
