[bug report] nvme-fc: improve memory usage in nvme_fc_rcv_ls_req()

[Chaitanya Kulkarni]

> On Dec 2, 2022, at 1:59 AM, Dan Carpenter <error27 at gmail.com> wrote:
> 
> Hello Christophe JAILLET,
> 
> The patch cf3d00840170: "nvme-fc: improve memory usage in
> nvme_fc_rcv_ls_req()" from Oct 2, 2022, leads to the following Smatch
> static checker warning:
> 
> drivers/nvme/host/fc.c:1757 nvme_fc_rcv_ls_req() error: potential null dereference 'lsop'.  (kzalloc returns null)
> drivers/nvme/host/fc.c:1759 nvme_fc_rcv_ls_req() warn: variable dereferenced before check 'lsop' (see line 1757)
> 
> drivers/nvme/host/fc.c
>    1747         if (lsreqbuf_len > sizeof(union nvmefc_ls_requests)) {
>    1748                 dev_info(lport->dev,
>    1749                         "RCV %s LS failed: payload too large\n",
>    1750                         (w0->ls_cmd <= NVME_FC_LAST_LS_CMD_VALUE) ?
>    1751                                 nvmefc_ls_names[w0->ls_cmd] : "");
>    1752                 ret = -E2BIG;
>    1753                 goto out_put;
>    1754         }
>    1755 
>    1756         lsop = kzalloc(sizeof(*lsop), GFP_KERNEL);
> --> 1757         lsop->rqstbuf = kzalloc(sizeof(*lsop->rqstbuf), GFP_KERNEL);
>                 ^^^^^^^^^^^^^
> 
>    1758         lsop->rspbuf = kzalloc(sizeof(*lsop->rspbuf), GFP_KERNEL);
>    1759         if (!lsop || !lsop->rqstbuf || !lsop->rspbuf) {
>                      ^^^^
> 
>    1760                 dev_info(lport->dev,
>    1761                         "RCV %s LS failed: No memory\n",
>    1762                         (w0->ls_cmd <= NVME_FC_LAST_LS_CMD_VALUE) ?
>    1763                                 nvmefc_ls_names[w0->ls_cmd] : "");
>    1764                 ret = -ENOMEM;
>    1765                 goto out_free;
>    1766         }
>    1767 
> 
> regards,
> dan carpenter
> 

I already sent out a fix on NVMe mailing list ...

-ck