From: Eduard Zingerman <eddyz87@gmail.com>
To: Alan Maguire <alan.maguire@oracle.com>, ast@kernel.org
Cc: daniel@iogearbox.net, andrii@kernel.org, martin.lau@linux.dev,
memxor@gmail.com, song@kernel.org, yonghong.song@linux.dev,
jolsa@kernel.org, bpf@vger.kernel.org,
Kaitao Cheng <pilgrimtao@gmail.com>
Subject: Re: [PATCH bpf-next] Fix undefined symbol references for module build post cnum changes
Date: Mon, 27 Apr 2026 10:07:28 -0700 [thread overview]
Message-ID: <81b78478b1345151539578cd486b7c656249b441.camel@gmail.com> (raw)
In-Reply-To: <686d51d3081a3c34ce644ac6d52c8b8e41864192.camel@gmail.com>
On Mon, 2026-04-27 at 09:44 -0700, Eduard Zingerman wrote:
> On Mon, 2026-04-27 at 12:22 +0100, Alan Maguire wrote:
> > Seeing the following on bpf-next:
> >
> > DESCEND objtool
> > DESCEND bpf/resolve_btfids
> > INSTALL libsubcmd_headers
> > INSTALL libsubcmd_headers
> > MODPOST Module.symvers
> > ERROR: modpost: "cnum64_umin" [drivers/net/ethernet/netronome/nfp/nfp.ko] undefined!
> > ERROR: modpost: "cnum64_umax" [drivers/net/ethernet/netronome/nfp/nfp.ko] undefined!
> > make[2]: *** [scripts/Makefile.modpost:147: Module.symvers] Error 1
> > make[1]: *** [bpf-next/Makefile:2089: modpost] Error 2
> > make: *** [Makefile:248: __sub-make] Error 2
> >
> > Further investigation suggests nfp indeed does pull in those symbols,
> > likely due to references in include/linux/bpf_verifier.h:
> >
> > static inline s64 reg_smax(const struct bpf_reg_state *reg)
> > {
> > return cnum64_smax(reg->r64);
> > }
> >
> > static inline u64 reg_umin(const struct bpf_reg_state *reg)
> > {
> > return cnum64_umin(reg->r64);
> > }
> >
> > ...
> >
> > Export symbols for these references.
> >
> > Reported-by: Kaitao Cheng <pilgrimtao@gmail.com>
> > Fixes: bbc631085503 ("bpf: replace min/max fields with struct cnum{32,64}")
> > Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
> > ---
>
> Hi Alan,
>
> thank you for the fix, apologies for breaking this.
>
> Acked-by: Eduard Zingerman <eddyz87@gmail.com>
However, Alexei raises a valid question.
Netronome code uses the following accessors:
- cnum{32,64}_reg_umin
- cnum{32,64}_reg_umax
However, this patch also exports the following on top:
- cnum{32,64}_from_{urange,srange}
- cnum{32,64}_reg_smin
- cnum{32,64}_reg_smax
Why export extra accessors?
next prev parent reply other threads:[~2026-04-27 17:07 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-27 11:22 [PATCH bpf-next] Fix undefined symbol references for module build post cnum changes Alan Maguire
2026-04-27 12:08 ` Chengkaitao
2026-04-27 16:44 ` Eduard Zingerman
2026-04-27 17:07 ` Eduard Zingerman [this message]
2026-04-27 17:11 ` Alexei Starovoitov
2026-04-29 17:10 ` Alan Maguire
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