Re: [PATCH] octeontx2-af: Fix use of uninitialized pointer bmap

From: David Miller
Date: Fri Jul 24 2020 - 19:57:26 EST

From: Dinghao Liu <dinghao.liu@xxxxxxxxxx>
Date: Fri, 24 Jul 2020 16:06:57 +0800

> If req->ctype does not match any of NIX_AQ_CTYPE_CQ,
> NIX_AQ_CTYPE_SQ or NIX_AQ_CTYPE_RQ, pointer bmap will remain
> uninitialized and be accessed in test_bit(), which can lead
> to kernal crash.

This can never happen.

> Fix this by returning an error code if this case is triggered.
> Signed-off-by: Dinghao Liu <dinghao.liu@xxxxxxxxxx>

I strongly dislike changes like this.

Most callers of nix_lf_hwctx_disable() inside of rvu_nix.c set
req->ctype to one of the handled values.

The only other case, rvu_mbox_handler_nix_hwctx_disable(), is a
completely unused function and should be removed.

There is no functional problem in this code at all.

It is not possible show a code path where the stated problem can
actually occur.