4.20-stable review patch. If anyone has any objections, please let me know.
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From: Bart Van Assche bvanassche@acm.org
commit 48396e80fb6526ea5ed267bd84f028bae56d2f9e upstream.
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: stable@vger.kernel.org Fixes: 94a9174c630c ("IB/srp: reduce lock coverage of command completion") Signed-off-by: Bart Van Assche bvanassche@acm.org Signed-off-by: Jason Gunthorpe jgg@mellanox.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/infiniband/ulp/srp/ib_srp.c | 10 ---------- 1 file changed, 10 deletions(-)
--- a/drivers/infiniband/ulp/srp/ib_srp.c +++ b/drivers/infiniband/ulp/srp/ib_srp.c @@ -2942,7 +2942,6 @@ static int srp_reset_device(struct scsi_ { 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"); @@ -2954,15 +2953,6 @@ static int srp_reset_device(struct scsi_ 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; }