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Joe Lawrence authored
This patch fixes a reference count bug in the SCSI tape driver which can be reproduced with the following: * Boot with slub_debug=FZPU, tape drive attached * echo 1 > /sys/devices/... tape device pci path .../remove * Wait for device removal * echo 1 > /sys/kernel/slab/blkdev_queue/validate * Slub debug complains about corrupted poison pattern In commit 523e1d39 (block: make gendisk hold a reference to its queue) add_disk() and disk_release() were modified to get/put an additional reference on a disk queue to fix a reference counting discrepency between bdev release and SCSI device removal. The ST driver never calls add_disk(), so this commit introduced an extra kref put when the ST driver frees its struct gendisk. Attempts were made to fix this bug at the block level [1] but later abandoned due to floppy driver issues [2]. [1] https://lkml.org/lkml/2012/8/27/354 [2] https://lkml.org/lkml/2012/9/22/113Signed-off-by: Joe Lawrence <joe.lawrence@stratus.com> Tested-by: Ewan D. Milne <emilne@redhat.com> Acked-by: Kai Mäkisara <Kai.Makisara@kolumbus.fi> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
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