[PATCH bpf-next v2] bpf: Fix 'dubious one-bit signed bitfield' warnings

Matthieu Baerts posted 1 patch 2 months, 2 weeks ago
Patches applied successfully (tree, apply log)
git fetch https://github.com/multipath-tcp/mptcp_net-next tags/patchew/20220711081200.2081262-1-matthieu.baerts@tessares.net
Maintainers: Hao Luo <haoluo@google.com>, Daniel Borkmann <daniel@iogearbox.net>, Eduard Zingerman <eddyz87@gmail.com>, John Fastabend <john.fastabend@gmail.com>, Andrii Nakryiko <andrii@kernel.org>, Song Liu <song@kernel.org>, KP Singh <kpsingh@kernel.org>, Yonghong Song <yhs@fb.com>, Stanislav Fomichev <sdf@google.com>, Martin KaFai Lau <martin.lau@linux.dev>, Alexei Starovoitov <ast@kernel.org>, Jiri Olsa <jolsa@kernel.org>
include/linux/bpf_verifier.h | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
[PATCH bpf-next v2] bpf: Fix 'dubious one-bit signed bitfield' warnings
Posted by Matthieu Baerts 2 months, 2 weeks ago
Our CI[1] reported these warnings when using Sparse:

  $ touch net/mptcp/bpf.c
  $ make C=1 net/mptcp/bpf.o
  net/mptcp/bpf.c: note: in included file:
  include/linux/bpf_verifier.h:348:26: error: dubious one-bit signed bitfield
  include/linux/bpf_verifier.h:349:29: error: dubious one-bit signed bitfield

Set them as 'unsigned' to avoid warnings.

[1] https://github.com/multipath-tcp/mptcp_net-next/actions/runs/2643588487

Fixes: 1ade23711971 ("bpf: Inline calls to bpf_loop when callback is known")
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
---

Notes:
    v2: switch from 'bool' to 'unsigned int' (Yonghong Song)

 include/linux/bpf_verifier.h | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h
index 81b19669efba..2e3bad8640dc 100644
--- a/include/linux/bpf_verifier.h
+++ b/include/linux/bpf_verifier.h
@@ -345,10 +345,10 @@ struct bpf_verifier_state_list {
 };
 
 struct bpf_loop_inline_state {
-	int initialized:1; /* set to true upon first entry */
-	int fit_for_inline:1; /* true if callback function is the same
-			       * at each call and flags are always zero
-			       */
+	unsigned int initialized:1; /* set to true upon first entry */
+	unsigned int fit_for_inline:1; /* true if callback function is the same
+					* at each call and flags are always zero
+					*/
 	u32 callback_subprogno; /* valid when fit_for_inline is true */
 };
 
-- 
2.36.1


Re: [PATCH bpf-next v2] bpf: Fix 'dubious one-bit signed bitfield' warnings
Posted by patchwork-bot+netdevbpf@kernel.org 2 months, 2 weeks ago
Hello:

This patch was applied to bpf/bpf-next.git (master)
by Andrii Nakryiko <andrii@kernel.org>:

On Mon, 11 Jul 2022 10:12:00 +0200 you wrote:
> Our CI[1] reported these warnings when using Sparse:
> 
>   $ touch net/mptcp/bpf.c
>   $ make C=1 net/mptcp/bpf.o
>   net/mptcp/bpf.c: note: in included file:
>   include/linux/bpf_verifier.h:348:26: error: dubious one-bit signed bitfield
>   include/linux/bpf_verifier.h:349:29: error: dubious one-bit signed bitfield
> 
> [...]

Here is the summary with links:
  - [bpf-next,v2] bpf: Fix 'dubious one-bit signed bitfield' warnings
    https://git.kernel.org/bpf/bpf-next/c/f16214c102f0

You are awesome, thank you!
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Re: [PATCH bpf-next v2] bpf: Fix 'dubious one-bit signed bitfield' warnings
Posted by Yonghong Song 2 months, 2 weeks ago

On 7/11/22 1:12 AM, Matthieu Baerts wrote:
> Our CI[1] reported these warnings when using Sparse:
> 
>    $ touch net/mptcp/bpf.c
>    $ make C=1 net/mptcp/bpf.o
>    net/mptcp/bpf.c: note: in included file:
>    include/linux/bpf_verifier.h:348:26: error: dubious one-bit signed bitfield
>    include/linux/bpf_verifier.h:349:29: error: dubious one-bit signed bitfield
> 
> Set them as 'unsigned' to avoid warnings.
> 
> [1] https://github.com/multipath-tcp/mptcp_net-next/actions/runs/2643588487
> 
> Fixes: 1ade23711971 ("bpf: Inline calls to bpf_loop when callback is known")
> Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>

Acked-by: Yonghong Song <yhs@fb.com>