[PATCH AUTOSEL 4.9 2/5] scsi: core: Fix error handling of scsi_host_alloc()

* [PATCH AUTOSEL 4.9 2/5] scsi: core: Fix error handling of scsi_host_alloc()
       [not found] <20210615155039.63348-1-sashal@kernel.org>
@ 2021-06-15 15:50 ` Sasha Levin
  2021-06-15 15:50 ` [PATCH AUTOSEL 4.9 3/5] scsi: core: Put .shost_dev in failure path if host state changes to RUNNING Sasha Levin
  2021-06-15 15:50 ` [PATCH AUTOSEL 4.9 4/5] scsi: core: Only put parent device if host state differs from SHOST_CREATED Sasha Levin
  2 siblings, 0 replies; 3+ messages in thread
From: Sasha Levin @ 2021-06-15 15:50 UTC (permalink / raw)
  To: linux-kernel, stable
  Cc: Ming Lei, Bart Van Assche, John Garry, Hannes Reinecke,
	Martin K . Petersen, Sasha Levin, linux-scsi

From: Ming Lei <ming.lei@redhat.com>

[ Upstream commit 66a834d092930cf41d809c0e989b13cd6f9ca006 ]

After device is initialized via device_initialize(), or its name is set via
dev_set_name(), the device has to be freed via put_device().  Otherwise
device name will be leaked because it is allocated dynamically in
dev_set_name().

Fix the leak by replacing kfree() with put_device(). Since
scsi_host_dev_release() properly handles IDA and kthread removal, remove
special-casing these from the error handling as well.

Link: https://lore.kernel.org/r/20210602133029.2864069-2-ming.lei@redhat.com
Cc: Bart Van Assche <bvanassche@acm.org>
Cc: John Garry <john.garry@huawei.com>
Cc: Hannes Reinecke <hare@suse.de>
Tested-by: John Garry <john.garry@huawei.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: John Garry <john.garry@huawei.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/scsi/hosts.c | 23 +++++++++++++----------
 1 file changed, 13 insertions(+), 10 deletions(-)

diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
index 258a3f9a2519..5722ee66d3aa 100644
--- a/drivers/scsi/hosts.c
+++ b/drivers/scsi/hosts.c
@@ -421,8 +421,10 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
 	mutex_init(&shost->scan_mutex);
 
 	index = ida_simple_get(&host_index_ida, 0, 0, GFP_KERNEL);
-	if (index < 0)
-		goto fail_kfree;
+	if (index < 0) {
+		kfree(shost);
+		return NULL;
+	}
 	shost->host_no = index;
 
 	shost->dma_channel = 0xff;
@@ -509,7 +511,7 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
 		shost_printk(KERN_WARNING, shost,
 			"error handler thread failed to spawn, error = %ld\n",
 			PTR_ERR(shost->ehandler));
-		goto fail_index_remove;
+		goto fail;
 	}
 
 	shost->tmf_work_q = alloc_workqueue("scsi_tmf_%d",
@@ -518,17 +520,18 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
 	if (!shost->tmf_work_q) {
 		shost_printk(KERN_WARNING, shost,
 			     "failed to create tmf workq\n");
-		goto fail_kthread;
+		goto fail;
 	}
 	scsi_proc_hostdir_add(shost->hostt);
 	return shost;
+ fail:
+	/*
+	 * Host state is still SHOST_CREATED and that is enough to release
+	 * ->shost_gendev. scsi_host_dev_release() will free
+	 * dev_name(&shost->shost_dev).
+	 */
+	put_device(&shost->shost_gendev);
 
- fail_kthread:
-	kthread_stop(shost->ehandler);
- fail_index_remove:
-	ida_simple_remove(&host_index_ida, shost->host_no);
- fail_kfree:
-	kfree(shost);
 	return NULL;
 }
 EXPORT_SYMBOL(scsi_host_alloc);
-- 
2.30.2


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