[SCSI] sd: fix crash when UA received on DIF enabled device
sd_prep_fn will allocate a larger CDB for the command via mempool_alloc for devices using DIF type 2 protection. This CDB was being freed in sd_done, which results in a kernel crash if the command is retried due to a UNIT ATTENTION. This change moves the code to free the larger CDB into sd_unprep_fn instead, which is invoked after the request is complete. It is no longer necessary to call scsi_print_command separately for this case as the ->cmnd will no longer be NULL in the normal code path. Also removed conditional test for DIF type 2 when freeing the larger CDB because the protection_type could have been changed via sysfs while the command was executing. Signed-off-by: Ewan D. Milne <emilne@redhat.com> Acked-by: Martin K. Petersen <martin.petersen@oracle.com> Cc: <stable@vger.kernel.org> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
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@ -838,10 +838,17 @@ static int scsi_setup_flush_cmnd(struct scsi_device *sdp, struct request *rq)
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static void sd_unprep_fn(struct request_queue *q, struct request *rq)
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{
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struct scsi_cmnd *SCpnt = rq->special;
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if (rq->cmd_flags & REQ_DISCARD) {
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free_page((unsigned long)rq->buffer);
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rq->buffer = NULL;
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}
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if (SCpnt->cmnd != rq->cmd) {
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mempool_free(SCpnt->cmnd, sd_cdb_pool);
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SCpnt->cmnd = NULL;
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SCpnt->cmd_len = 0;
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}
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}
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/**
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@ -1720,21 +1727,6 @@ static int sd_done(struct scsi_cmnd *SCpnt)
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if (rq_data_dir(SCpnt->request) == READ && scsi_prot_sg_count(SCpnt))
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sd_dif_complete(SCpnt, good_bytes);
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if (scsi_host_dif_capable(sdkp->device->host, sdkp->protection_type)
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== SD_DIF_TYPE2_PROTECTION && SCpnt->cmnd != SCpnt->request->cmd) {
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/* We have to print a failed command here as the
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* extended CDB gets freed before scsi_io_completion()
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* is called.
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*/
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if (result)
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scsi_print_command(SCpnt);
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mempool_free(SCpnt->cmnd, sd_cdb_pool);
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SCpnt->cmnd = NULL;
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SCpnt->cmd_len = 0;
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}
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return good_bytes;
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}
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