Since .scsi_done() must only be called after scsi_queue_rq() has finished, make sure that the SRP initiator driver does not call .scsi_done() while scsi_queue_rq() is in progress. Although invoking sg_reset -d while I/O is in progress works fine with kernel v4.20 and before, that is not the case with kernel v5.0-rc1. This patch avoids that the following crash is triggered with kernel v5.0-rc1:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000138 CPU: 0 PID: 360 Comm: kworker/0:1H Tainted: G B 5.0.0-rc1-dbg+ #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014 Workqueue: kblockd blk_mq_run_work_fn RIP: 0010:blk_mq_dispatch_rq_list+0x116/0xb10 Call Trace: blk_mq_sched_dispatch_requests+0x2f7/0x300 __blk_mq_run_hw_queue+0xd6/0x180 blk_mq_run_work_fn+0x27/0x30 process_one_work+0x4f1/0xa20 worker_thread+0x67/0x5b0 kthread+0x1cf/0x1f0 ret_from_fork+0x24/0x30
Cc: Sergey Gorenko sergeygo@mellanox.com Cc: Max Gurtovoy maxg@mellanox.com Cc: Laurence Oberman loberman@redhat.com Cc: stable@vger.kernel.org Fixes: 94a9174c630c ("IB/srp: reduce lock coverage of command completion") # v2.6.38 Signed-off-by: Bart Van Assche bvanassche@acm.org ---
Changes compared to v1: left out the code that waits until in-progress requests have finished.
drivers/infiniband/ulp/srp/ib_srp.c | 10 ---------- 1 file changed, 10 deletions(-)
diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c index af5197b5e7f1..085dba075651 100644 --- a/drivers/infiniband/ulp/srp/ib_srp.c +++ b/drivers/infiniband/ulp/srp/ib_srp.c @@ -3037,7 +3037,6 @@ static int srp_reset_device(struct scsi_cmnd *scmnd) { struct srp_target_port *target = host_to_target(scmnd->device->host); struct srp_rdma_ch *ch; - int i, j; u8 status;
shost_printk(KERN_ERR, target->scsi_host, "SRP reset_device called\n"); @@ -3049,15 +3048,6 @@ static int srp_reset_device(struct scsi_cmnd *scmnd) if (status) return FAILED;
- for (i = 0; i < target->ch_count; i++) { - ch = &target->ch[i]; - for (j = 0; j < target->req_ring_size; ++j) { - struct srp_request *req = &ch->req_ring[j]; - - srp_finish_req(ch, req, scmnd->device, DID_RESET << 16); - } - } - return SUCCESS; }