From fe442604199ed3e60d5411137159f9623534e956 Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Thu, 28 Jul 2022 15:18:48 -0700 Subject: scsi: core: Make sure that targets outlive devices This commit prevents that the following sequence triggers a kernel crash: - Deletion of a SCSI device is requested via sysfs. Device removal takes some time because blk_cleanup_queue() is waiting for the SCSI error handler. - The SCSI target associated with that SCSI device is removed. - scsi_remove_target() returns and its caller frees the resources associated with the SCSI target. - The error handler makes progress and invokes an LLD callback that dereferences the SCSI target pointer. Link: https://lore.kernel.org/r/20220728221851.1822295-2-bvanassche@acm.org Cc: Christoph Hellwig Cc: Mike Christie Cc: Hannes Reinecke Cc: John Garry Cc: Li Zhijian Reported-by: Mike Christie Reviewed-by: Ming Lei Reviewed-by: Mike Christie Signed-off-by: Bart Van Assche Signed-off-by: Martin K. Petersen --- include/scsi/scsi_device.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/scsi') diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h index 7cf5f3b7589f..190d2081f4c6 100644 --- a/include/scsi/scsi_device.h +++ b/include/scsi/scsi_device.h @@ -309,6 +309,8 @@ struct scsi_target { struct list_head devices; struct device dev; struct kref reap_ref; /* last put renders target invisible */ + atomic_t sdev_count; + wait_queue_head_t sdev_wq; unsigned int channel; unsigned int id; /* target id ... replace * scsi_device.id eventually */ -- cgit v1.2.3-70-g09d2