[PATCH 2.6.14.3] SCSI: fix transfer direction in sd (kernel panic when ejecting iPod) sd_init_command could issue WRITE requests with zero buffer length. This may lead to kernel panic or oops with some SCSI low-level drivers. Seen with the command "eject /dev/sdX" when disconnecting an iPod: http://marc.theaimsgroup.com/?l=linux1394-devel&m=113399994920181 http://marc.theaimsgroup.com/?l=linux1394-user&m=112152701817435 Derived from -rc patches from Jens Axboe and James Bottomley. Signed-off-by: Stefan Richter --- Patch is reassembled for -stable from patches: [SCSI] fix panic when ejecting ieee1394 ipod [SCSI] Consolidate REQ_BLOCK_PC handling path (fix ipod panic) drivers/scsi/scsi_lib.c | 20 ++++++++++++++++++++ drivers/scsi/sd.c | 16 +--------------- include/scsi/scsi_cmnd.h | 1 + 3 files changed, 22 insertions(+), 15 deletions(-) --- linux-2.6.14.3/drivers/scsi.orig/scsi_lib.c 2005-11-24 23:10:21.000000000 +0100 +++ linux-2.6.14.3/drivers/scsi/scsi_lib.c 2005-12-14 22:23:13.000000000 +0100 @@ -1129,6 +1129,26 @@ static void scsi_generic_done(struct scs scsi_io_completion(cmd, cmd->result == 0 ? cmd->bufflen : 0, 0); } +void scsi_setup_blk_pc_cmnd(struct scsi_cmnd *cmd, int retries) +{ + struct request *req = cmd->request; + + BUG_ON(sizeof(req->cmd) > sizeof(cmd->cmnd)); + memcpy(cmd->cmnd, req->cmd, sizeof(cmd->cmnd)); + cmd->cmd_len = req->cmd_len; + if (!req->data_len) + cmd->sc_data_direction = DMA_NONE; + else if (rq_data_dir(req) == WRITE) + cmd->sc_data_direction = DMA_TO_DEVICE; + else + cmd->sc_data_direction = DMA_FROM_DEVICE; + + cmd->transfersize = req->data_len; + cmd->allowed = retries; + cmd->timeout_per_command = req->timeout; +} +EXPORT_SYMBOL_GPL(scsi_setup_blk_pc_cmnd); + static int scsi_prep_fn(struct request_queue *q, struct request *req) { struct scsi_device *sdev = q->queuedata; --- linux-2.6.14.3/drivers/scsi.orig/sd.c 2005-11-24 23:10:21.000000000 +0100 +++ linux-2.6.14.3/drivers/scsi/sd.c 2005-12-14 22:23:13.000000000 +0100 @@ -231,24 +231,10 @@ static int sd_init_command(struct scsi_c * SG_IO from block layer already setup, just copy cdb basically */ if (blk_pc_request(rq)) { - if (sizeof(rq->cmd) > sizeof(SCpnt->cmnd)) - return 0; - - memcpy(SCpnt->cmnd, rq->cmd, sizeof(SCpnt->cmnd)); - SCpnt->cmd_len = rq->cmd_len; - if (rq_data_dir(rq) == WRITE) - SCpnt->sc_data_direction = DMA_TO_DEVICE; - else if (rq->data_len) - SCpnt->sc_data_direction = DMA_FROM_DEVICE; - else - SCpnt->sc_data_direction = DMA_NONE; - - this_count = rq->data_len; + scsi_setup_blk_pc_cmnd(SCpnt, SD_PASSTHROUGH_RETRIES); if (rq->timeout) timeout = rq->timeout; - SCpnt->transfersize = rq->data_len; - SCpnt->allowed = SD_PASSTHROUGH_RETRIES; goto queue; } --- linux-2.6.14.3/include/scsi.orig/scsi_cmnd.h 2005-11-24 23:10:21.000000000 +0100 +++ linux-2.6.14.3/include/scsi/scsi_cmnd.h 2005-12-14 22:23:14.000000000 +0100 @@ -150,5 +150,6 @@ extern struct scsi_cmnd *scsi_get_comman extern void scsi_put_command(struct scsi_cmnd *); extern void scsi_io_completion(struct scsi_cmnd *, unsigned int, unsigned int); extern void scsi_finish_command(struct scsi_cmnd *cmd); +extern void scsi_setup_blk_pc_cmnd(struct scsi_cmnd *cmd, int retries); #endif /* _SCSI_SCSI_CMND_H */