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

Stephen Rothwell
2022-02-08T05:32:30Z

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Hi all,

[Cc'ing the scsi maintainers. Sorry I should have done that sooner]

On Mon, 24 Jan 2022 19:43:44 -0800 Kees Cook <keescook@chromium.org> wrote:
>
> On Tue, Jan 25, 2022 at 02:24:30PM +1100, Stephen Rothwell wrote:
> >
> > 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 <sfr@canb.auug.org.au>
> > Date: Tue, 25 Jan 2022 14:18:36 +1100
> > Subject: [PATCH] scsi: hack for building with -Warray-bounds
> >
> > Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
> > ---
> > 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",
>
> This looks correct to me. struct viosrp_crq is 16 bytes wide. The only
> suggestion I might make would be either avoid the bare '2':
>
> u64 msg_hi[sizeof(struct viosrp_crq) / sizeof(u64)] = { };
>
> or adjust struct viosrp_crq so the casting isn't needed at all:
>
>
> truct viosrp_crq {
> union {
> u64 hi;
> struct {
> u8 valid; /* used by RPA */
> u8 format; /* SCSI vs out-of-band */
> u8 reserved;
> u8 status; /* non-scsi failure? (e.g. DMA failure) */
> __be16 timeout; /* in seconds */
> __be16 IU_length; /* in bytes */
> };
> };
> __be64 IU_data_ptr; /* the TCE for transferring data */
> };
>
> struct viosrp_crq crq = { };
> ...
> rc = h_send_crq(vscsi->dma_dev->unit_address,
> be64_to_cpu(crq.hi),
> be64_to_cpu(cmd->rsp.tag));
>
>
>

Has there been any progress on this?

Commit 88a678bbc34c mentioned above was merged in v4.8-rc1.

--
Cheers,
Stephen Rothwell

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