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Commit 8d5dbec3 authored Feb 23, 2016 by Finn Thain Committed by Martin K. Petersen Mar 01, 2016

ncr5380: Call scsi_eh_prep_cmnd() and scsi_eh_restore_cmnd() as and when appropriate

This bug causes the wrong command to have its sense pointer overwritten,
which sometimes leads to a NULL pointer deref. Fix this by checking which
command is being requeued before restoring the scsi_eh_save data.

It turns out that some targets will disconnect a REQUEST SENSE command.
The autosense algorithm doesn't anticipate this. Hence multiple commands
can end up undergoing autosense simultaneously, and they will all try to
use the same scsi_eh_save struct, which won't work. Defer autosense when
the scsi_eh_save storage is in use by another command.

Fixes: f27db8eb ("ncr5380: Fix autosense bugs")
Reported-and-tested-by: Michael Schmitz <schmitzmic@gmail.com>
Cc: <stable@vger.kernel.org> # 4.5
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

parent ccf6efd7

drivers/scsi/NCR5380.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -760,7 +760,7 @@ static struct scsi_cmnd dequeue_next_cmd(struct Scsi_Host instance)
		struct NCR5380_cmd *ncmd;
		struct scsi_cmnd *cmd;

		if (list_empty(&hostdata->autosense)) {
		if (hostdata->sensing \|\| list_empty(&hostdata->autosense)) {
		list_for_each_entry(ncmd, &hostdata->unissued, list) {
		cmd = NCR5380_to_scmd(ncmd);
		dsprintk(NDEBUG_QUEUES, instance, "dequeue: cmd=%p target=%d busy=0x%02x lun=%llu\n",
		@@ -793,7 +793,7 @@ static void requeue_cmd(struct Scsi_Host instance, struct scsi_cmnd cmd)
		struct NCR5380_hostdata *hostdata = shost_priv(instance);
		struct NCR5380_cmd *ncmd = scsi_cmd_priv(cmd);

		if (hostdata->sensing) {
		if (hostdata->sensing == cmd) {
		scsi_eh_restore_cmnd(cmd, &hostdata->ses);
		list_add(&ncmd->list, &hostdata->autosense);
		hostdata->sensing = NULL;

drivers/scsi/atari_NCR5380.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -862,7 +862,7 @@ static struct scsi_cmnd dequeue_next_cmd(struct Scsi_Host instance)
		struct NCR5380_cmd *ncmd;
		struct scsi_cmnd *cmd;

		if (list_empty(&hostdata->autosense)) {
		if (hostdata->sensing \|\| list_empty(&hostdata->autosense)) {
		list_for_each_entry(ncmd, &hostdata->unissued, list) {
		cmd = NCR5380_to_scmd(ncmd);
		dsprintk(NDEBUG_QUEUES, instance, "dequeue: cmd=%p target=%d busy=0x%02x lun=%llu\n",
		@@ -901,7 +901,7 @@ static void requeue_cmd(struct Scsi_Host instance, struct scsi_cmnd cmd)
		struct NCR5380_hostdata *hostdata = shost_priv(instance);
		struct NCR5380_cmd *ncmd = scsi_cmd_priv(cmd);

		if (hostdata->sensing) {
		if (hostdata->sensing == cmd) {
		scsi_eh_restore_cmnd(cmd, &hostdata->ses);
		list_add(&ncmd->list, &hostdata->autosense);
		hostdata->sensing = NULL;