A bug in scsi_alloc_target of drivers/scsi/scsi_scan.c

From: Dashi DS1 Cao
Date: Tue May 09 2017 - 05:10:48 EST


When debugging a race condition in scsi_remove_target of 3.12, I ran into this possible bug within scsi_alloc_target.
When an existing "struct scsi_target" is found and used, the starget just got through kzmalloc should be freed, rather than dong a "put_device(dev)".

diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index 81d4151..96795d4 100644
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -483,7 +483,7 @@ static struct scsi_target *scsi_alloc_target(struct device *parent,

spin_unlock_irqrestore(shost->host_lock, flags);
if (ref_got) {
- put_device(dev);
+ kfree(starget);
return found_target;
}
/*
--

Dashi Cao