ACK: [SRU][X][PATCH 1/1] UBUNTU: SAUCE: (no-up) arch/x86/bpf: Fix missed return statement

[Khaled Elmously]

On 2018-01-25 23:58:20 , Daniel Axtens wrote:
> BugLink: https://bugs.launchpad.net/bugs/1745364
> 
> Coverity reports:
> 
> *** CID 1464330: Uninitialized variables (MISSING_RETURN)
> /arch/x86/net/bpf_jit_comp.c: 1088 in bpf_int_jit_compile()
> 1082 int i;
> 1083 1084 if (!bpf_jit_enable)
> 1085 return prog;
> 1086 1087 if (!prog || !prog->len)
> >>> CID 1464330: Uninitialized variables (MISSING_RETURN)
> >>> Arriving at the end of a function without returning a value.
> 1088 return;
> 1089 1090 addrs = kmalloc(prog->len * sizeof(*addrs), GFP_KERNEL);
> 1091 if (!addrs)
> 1092 return prog;
> 1093
> 
> This is a result of
> 3098d8eae421 ("bpf: prepare bpf_int_jit_compile/bpf_prog_select_runtime apis"),
> which is a cherry-pick of d1c55ab5e41f upstream. In that patch, the
> return type of bpf_int_jit_compile was changed from void to
> struct bpf_prog*. That patch changed some of the return statements.
> 
> It did not change the return statement of the (!prog || !prog->len)
> check, as in upstream the (!prog || !prog->len) check was dropped
> in 93a73d442d37 ("bpf, x86/arm64: remove useless checks on prog"):
> 
> """
> There is never such a situation, where bpf_int_jit_compile() is
> called with either prog as NULL or len as 0, so the tests are
> unnecessary and confusing as people would just copy them.
> """
> 
> However, we haven't picked up 93a73d442d37, so when we cherry-picked
> d1c55ab5e41f, that branch remained unmodified, hence the static
> analysis warning.
> 
> For consistency and in case the branch is not actually dead on Xenial,
> do a fixup to 'return prog;'
> 
> Fixes: 3098d8eae421 ("bpf: prepare bpf_int_jit_compile/bpf_prog_select_runtime apis")
> Cc: Andy Whitcroft <apw at canonical.com>
> Cc: Colin King <colin.king at canonical.com>
> Signed-off-by: Daniel Axtens <daniel.axtens at canonical.com>
> ---
>  arch/x86/net/bpf_jit_comp.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
> index 6c4279be4107..8553bbbea3f4 100644
> --- a/arch/x86/net/bpf_jit_comp.c
> +++ b/arch/x86/net/bpf_jit_comp.c
> @@ -1085,7 +1085,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
>  		return prog;
>  
>  	if (!prog || !prog->len)
> -		return;
> +		return prog;
>  
>  	addrs = kmalloc(prog->len * sizeof(*addrs), GFP_KERNEL);
>  	if (!addrs)

Acked-by: Khalid Elmously <khalid.elmously at canonical.com>