On Wed, 2017-05-10 at 14:07 -0700, Long Li wrote: > From: Long Li <[email protected]> > > Lower layer driver may not initialize private data before use. Zero them > out to prevent use of stale data. > > Signed-off-by: Long Li <[email protected]> > --- > drivers/scsi/scsi_lib.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c > index 19125d7..a821593 100644 > --- a/drivers/scsi/scsi_lib.c > +++ b/drivers/scsi/scsi_lib.c > @@ -1850,7 +1850,7 @@ static int scsi_mq_prep_fn(struct request *req) > > /* zero out the cmd, except for the embedded scsi_request */ > memset((char *)cmd + sizeof(cmd->req), 0, > - sizeof(*cmd) - sizeof(cmd->req)); > + sizeof(*cmd) - sizeof(cmd->req) + shost->hostt->cmd_size); > > req->special = cmd;
Hello Long, Sorry but this patch looks wrong to me. Since scsi_mq_prep_fn() is called after scsi_req_init(), erasing struct scsi_request from scsi_mq_prep_fn() will erase the values that were set by scsi_req_init(). That includes information like the pointer to the SCSI CDB and the CDB itself. See e.g. scsi_execute(). Did you come up with this patch after source reading or did you come up with this patch while chasing a bug? Thanks, Bart.
