2022-07-11 09:05:46

by Matthieu Baerts

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

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 <[email protected]>
---

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

2022-07-11 15:51:00

by Yonghong Song

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

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 <[email protected]>

Acked-by: Yonghong Song <[email protected]>

2022-07-12 05:30:50

by patchwork-bot+netdevbpf

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

Hello:

This patch was applied to bpf/bpf-next.git (master)
by Andrii Nakryiko <[email protected]>:

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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