Subject: linux-next: build failure after merge of the kspp tree

From: Stephen Rothwell <[email-masked]>
Date: Tue, 25 Jan 2022 14:24:30 +1100

Hi all,

After merging the kspp tree, today's linux-next build (powerpc
allyesconfig) failed like this:

drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c: In function 'ibmvscsis_send_messages':
drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c:1934:44: error: array subscript 'struct viosrp_crq[0]' is partly outside array bounds of 'u64[1]' {aka 'long long unsigned int[1]'} [-Werror=array-bounds]
 1934 |                                         crq->valid = VALID_CMD_RESP_EL;
      |                                            ^~
drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c:1875:13: note: while referencing 'msg_hi'
 1875 |         u64 msg_hi = 0;
      |             ^~~~~~
drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c:1935:44: error: array subscript 'struct viosrp_crq[0]' is partly outside array bounds of 'u64[1]' {aka 'long long unsigned int[1]'} [-Werror=array-bounds]
 1935 |                                         crq->format = cmd->rsp.format;
      |                                            ^~
drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c:1875:13: note: while referencing 'msg_hi'
 1875 |         u64 msg_hi = 0;
      |             ^~~~~~
drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c:1938:52: error: array subscript 'struct viosrp_crq[0]' is partly outside array bounds of 'u64[1]' {aka 'long long unsigned int[1]'} [-Werror=array-bounds]
 1938 |                                                 crq->status = VIOSRP_ADAPTER_FAIL;
      |                                                    ^~
drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c:1875:13: note: while referencing 'msg_hi'
 1875 |         u64 msg_hi = 0;
      |             ^~~~~~
drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c:1940:44: error: array subscript 'struct viosrp_crq[0]' is partly outside array bounds of 'u64[1]' {aka 'long long unsigned int[1]'} [-Werror=array-bounds]
 1940 |                                         crq->IU_length = cpu_to_be16(cmd->rsp.len);
      |                                            ^~
drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c:1875:13: note: while referencing 'msg_hi'
 1875 |         u64 msg_hi = 0;
      |             ^~~~~~

Exposed by commit

  4ba545781e20 ("Makefile: Enable -Warray-bounds")

Probably introduced by commit

  88a678bbc34c ("ibmvscsis: Initial commit of IBM VSCSI Tgt Driver")

I applied the following hack for now:

From: Stephen Rothwell <[email-masked]>
Date: Tue, 25 Jan 2022 14:18:36 +1100
Subject: [PATCH] scsi: hack for building with -Warray-bounds

Signed-off-by: Stephen Rothwell <[email-masked]>
---
 drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c b/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c
index 61f06f6885a5..89fcf98c61c3 100644
--- a/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c
+++ b/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c
@@ -1872,11 +1872,11 @@ static void srp_snd_msg_failed(struct scsi_info *vscsi, long rc)
  */
 static void ibmvscsis_send_messages(struct scsi_info *vscsi)
 {
-	u64 msg_hi = 0;
+	u64 msg_hi[2] = { };
 	/* note do not attempt to access the IU_data_ptr with this pointer
 	 * it is not valid
 	 */
-	struct viosrp_crq *crq = (struct viosrp_crq *)&msg_hi;
+	struct viosrp_crq *crq = (struct viosrp_crq *)msg_hi;
 	struct ibmvscsis_cmd *cmd, *nxt;
 	long rc = ADAPT_SUCCESS;
 	bool retry = false;
@@ -1940,7 +1940,7 @@ static void ibmvscsis_send_messages(struct scsi_info *vscsi)
 					crq->IU_length = cpu_to_be16(cmd->rsp.len);
 
 					rc = h_send_crq(vscsi->dma_dev->unit_address,
-							be64_to_cpu(msg_hi),
+							be64_to_cpu(msg_hi[0]),
 							be64_to_cpu(cmd->rsp.tag));
 
 					dev_dbg(&vscsi->dev, "send_messages: cmd %p, tag 0x%llx, rc %ld\n",
-- 
2.34.1

-- 
Cheers,
Stephen Rothwell