[PATCH 4.5 79/87] IB/srp: Fix a debug kernel crash

Greg Kroah-Hartman
2016-05-30T20:50:17Z

From: Bart Van Assche <bart.vanassche@sandisk.com>

commit 54f5c9c52d69afa55abf2b034df8d45f588466c3 upstream.

Avoid that the following BUG() is triggered against a debug
kernel:

kernel BUG at include/linux/scatterlist.h:92!
RIP: 0010:[<ffffffffa0467199>] [<ffffffffa0467199>] srp_map_idb+0x199/0x1a0 [ib_srp]
Call Trace:
[<ffffffffa04685fa>] srp_map_data+0x84a/0x890 [ib_srp]
[<ffffffffa0469674>] srp_queuecommand+0x1e4/0x610 [ib_srp]
[<ffffffff813f5a5e>] scsi_dispatch_cmd+0x9e/0x180
[<ffffffff813f8b07>] scsi_request_fn+0x477/0x610
[<ffffffff81298ffe>] __blk_run_queue+0x2e/0x40
[<ffffffff81299070>] blk_delay_work+0x20/0x30
[<ffffffff81071f07>] process_one_work+0x197/0x480
[<ffffffff81072239>] worker_thread+0x49/0x490
[<ffffffff810787ea>] kthread+0xea/0x100
[<ffffffff8159b632>] ret_from_fork+0x22/0x40

Fixes: f7f7aab1a5c0 ("IB/srp: Convert to new registration API")
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: Christoph Hellwig <hch@lst.de>
Reviewed-by: Max Gurtovoy <maxg@mellanox.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/infiniband/ulp/srp/ib_srp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -1541,7 +1541,7 @@ static int srp_map_idb(struct srp_rdma_c

if (dev->use_fast_reg) {
state.sg = idb_sg;
- sg_set_buf(idb_sg, req->indirect_desc, idb_len);
+ sg_init_one(idb_sg, req->indirect_desc, idb_len);
idb_sg->dma_address = req->indirect_dma_addr; /* hack! */
#ifdef CONFIG_NEED_SG_DMA_LENGTH
idb_sg->dma_length = idb_sg->length; /* hack^2 */