Hi,
在 2023/01/29 14:46, Greg KH 写道:
On Sun, Jan 29, 2023 at 09:13:55AM +0800, Yu Kuai wrote:
Hi, Greg
在 2023/01/28 18:45, Greg KH 写道:
diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index cac7c902cf70..a22109cdb8ef 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -1535,9 +1535,7 @@ static void __scsi_remove_target(struct scsi_target *starget)
if (sdev->channel != starget->channel ||
sdev->id != starget->id)
continue;
- if (sdev->sdev_state == SDEV_DEL ||
- sdev->sdev_state == SDEV_CANCEL ||
- !get_device(&sdev->sdev_gendev))
+ if (!get_device_unless_zero(&sdev->sdev_gendev))
If sdev_gendev is 0 here, the object is gone and you are working with
memory that is already freed so something is _VERY_ wrong.
In fact, this patch will work:
In __scsi_remove_target(), 'host_lock' is held to protect iterating
siblings, and object will wait for this lock in
scsi_device_dev_release() to remove siblings. Hence sdev will not be
freed untill the lock is released.
Then you got lucky, as that is not how a reference counted object should
be working (i.e. the reference dropped to 0 and it still be kept alive.)
Please fix up the scsi logic here, don't abuse the reference count code.
Thanks for the reply, I agree that we should fix this in scsi layer.
Kuai
