4.5-stable review patch. If anyone has any objections, please let me know.
------------------ From: Finn Thain <[email protected]> commit 8d5dbec3bcb24a7d071962448e0fecaca8c75cc7 upstream. 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: f27db8eb98a1 ("ncr5380: Fix autosense bugs") Reported-and-tested-by: Michael Schmitz <[email protected]> Signed-off-by: Finn Thain <[email protected]> Signed-off-by: Martin K. Petersen <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- drivers/scsi/NCR5380.c | 4 ++-- drivers/scsi/atari_NCR5380.c | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-) --- a/drivers/scsi/NCR5380.c +++ b/drivers/scsi/NCR5380.c @@ -760,7 +760,7 @@ static struct scsi_cmnd *dequeue_next_cm 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 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; --- a/drivers/scsi/atari_NCR5380.c +++ b/drivers/scsi/atari_NCR5380.c @@ -862,7 +862,7 @@ static struct scsi_cmnd *dequeue_next_cm 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 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;
