* [PATCH bpf 1/2] samples: bpf: fix xdp_sample_user.o linking with Clang
2021-12-03 19:50 [PATCH bpf 0/2] samples: bpf: fix build issues with Clang/LLVM Alexander Lobakin
@ 2021-12-03 19:50 ` Alexander Lobakin
2021-12-04 0:47 ` Kumar Kartikeya Dwivedi
2021-12-03 19:50 ` [PATCH bpf 2/2] samples: bpf: fix 'unknown warning group' build warning on Clang Alexander Lobakin
2021-12-07 3:35 ` [PATCH bpf 0/2] samples: bpf: fix build issues with Clang/LLVM Andrii Nakryiko
2 siblings, 1 reply; 6+ messages in thread
From: Alexander Lobakin @ 2021-12-03 19:50 UTC (permalink / raw)
To: Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko
Cc: Alexander Lobakin, Toke Høiland-Jørgensen,
Kumar Kartikeya Dwivedi, John Fastabend, Jesper Dangaard Brouer,
Nathan Chancellor, Nick Desaulniers, netdev, bpf, linux-kernel,
llvm
Clang (13) doesn't get the jokes about specifying libraries to link in
cclags of individual .o objects:
clang-13: warning: -lm: 'linker' input unused [-Wunused-command-line-argument]
[ ... ]
LD samples/bpf/xdp_redirect_cpu
LD samples/bpf/xdp_redirect_map_multi
LD samples/bpf/xdp_redirect_map
LD samples/bpf/xdp_redirect
LD samples/bpf/xdp_monitor
/usr/bin/ld: samples/bpf/xdp_sample_user.o: in function `sample_summary_print':
xdp_sample_user.c:(.text+0x84c): undefined reference to `floor'
/usr/bin/ld: xdp_sample_user.c:(.text+0x870): undefined reference to `ceil'
/usr/bin/ld: xdp_sample_user.c:(.text+0x8cf): undefined reference to `floor'
/usr/bin/ld: xdp_sample_user.c:(.text+0x8f3): undefined reference to `ceil'
[ more ]
Specify '-lm' as ldflags for all xdp_sample_user.o users in the main
Makefile and remove it from ccflags of ^ in Makefile.target -- just
like it's done for all other samples. This works with all compilers.
Fixes: 6e1051a54e31 ("samples: bpf: Convert xdp_monitor to XDP samples helper")
Fixes: b926c55d856c ("samples: bpf: Convert xdp_redirect to XDP samples helper")
Fixes: e531a220cc59 ("samples: bpf: Convert xdp_redirect_cpu to XDP samples helper")
Fixes: bbe65865aa05 ("samples: bpf: Convert xdp_redirect_map to XDP samples helper")
Fixes: 594a116b2aa1 ("samples: bpf: Convert xdp_redirect_map_multi to XDP samples helper")
Signed-off-by: Alexander Lobakin <alexandr.lobakin@intel.com>
---
samples/bpf/Makefile | 5 +++++
samples/bpf/Makefile.target | 2 +-
2 files changed, 6 insertions(+), 1 deletion(-)
diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index a886dff1ba89..e5b049ad5447 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -215,6 +215,11 @@ TPROGS_LDFLAGS := -L$(SYSROOT)/usr/lib
endif
TPROGS_LDLIBS += $(LIBBPF) -lelf -lz
+TPROGLDLIBS_xdp_monitor += -lm
+TPROGLDLIBS_xdp_redirect += -lm
+TPROGLDLIBS_xdp_redirect_cpu += -lm
+TPROGLDLIBS_xdp_redirect_map += -lm
+TPROGLDLIBS_xdp_redirect_map_multi += -lm
TPROGLDLIBS_tracex4 += -lrt
TPROGLDLIBS_trace_output += -lrt
TPROGLDLIBS_map_perf_test += -lrt
diff --git a/samples/bpf/Makefile.target b/samples/bpf/Makefile.target
index 5a368affa038..379560f11db4 100644
--- a/samples/bpf/Makefile.target
+++ b/samples/bpf/Makefile.target
@@ -76,7 +76,7 @@ $(tprog-cobjs): $(obj)/%.o: $(src)/%.c FORCE
# Override includes for xdp_sample_user.o because $(srctree)/usr/include in
# TPROGS_CFLAGS causes conflicts
-XDP_SAMPLE_CFLAGS += -Wall -O2 -lm \
+XDP_SAMPLE_CFLAGS += -Wall -O2 \
-I./tools/include \
-I./tools/include/uapi \
-I./tools/lib \
--
2.33.1
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH bpf 1/2] samples: bpf: fix xdp_sample_user.o linking with Clang
2021-12-03 19:50 ` [PATCH bpf 1/2] samples: bpf: fix xdp_sample_user.o linking with Clang Alexander Lobakin
@ 2021-12-04 0:47 ` Kumar Kartikeya Dwivedi
0 siblings, 0 replies; 6+ messages in thread
From: Kumar Kartikeya Dwivedi @ 2021-12-04 0:47 UTC (permalink / raw)
To: Alexander Lobakin
Cc: Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko,
Toke Høiland-Jørgensen, John Fastabend,
Jesper Dangaard Brouer, Nathan Chancellor, Nick Desaulniers,
netdev, bpf, linux-kernel, llvm
On Sat, Dec 04, 2021 at 01:20:03AM IST, Alexander Lobakin wrote:
> Clang (13) doesn't get the jokes about specifying libraries to link in
> cclags of individual .o objects:
>
> clang-13: warning: -lm: 'linker' input unused [-Wunused-command-line-argument]
> [ ... ]
> LD samples/bpf/xdp_redirect_cpu
> LD samples/bpf/xdp_redirect_map_multi
> LD samples/bpf/xdp_redirect_map
> LD samples/bpf/xdp_redirect
> LD samples/bpf/xdp_monitor
> /usr/bin/ld: samples/bpf/xdp_sample_user.o: in function `sample_summary_print':
> xdp_sample_user.c:(.text+0x84c): undefined reference to `floor'
> /usr/bin/ld: xdp_sample_user.c:(.text+0x870): undefined reference to `ceil'
> /usr/bin/ld: xdp_sample_user.c:(.text+0x8cf): undefined reference to `floor'
> /usr/bin/ld: xdp_sample_user.c:(.text+0x8f3): undefined reference to `ceil'
> [ more ]
>
> Specify '-lm' as ldflags for all xdp_sample_user.o users in the main
> Makefile and remove it from ccflags of ^ in Makefile.target -- just
> like it's done for all other samples. This works with all compilers.
>
> Fixes: 6e1051a54e31 ("samples: bpf: Convert xdp_monitor to XDP samples helper")
> Fixes: b926c55d856c ("samples: bpf: Convert xdp_redirect to XDP samples helper")
> Fixes: e531a220cc59 ("samples: bpf: Convert xdp_redirect_cpu to XDP samples helper")
> Fixes: bbe65865aa05 ("samples: bpf: Convert xdp_redirect_map to XDP samples helper")
> Fixes: 594a116b2aa1 ("samples: bpf: Convert xdp_redirect_map_multi to XDP samples helper")
> Signed-off-by: Alexander Lobakin <alexandr.lobakin@intel.com>
> ---
Thanks, something to remember to test for next time.
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
--
Kartikeya
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH bpf 2/2] samples: bpf: fix 'unknown warning group' build warning on Clang
2021-12-03 19:50 [PATCH bpf 0/2] samples: bpf: fix build issues with Clang/LLVM Alexander Lobakin
2021-12-03 19:50 ` [PATCH bpf 1/2] samples: bpf: fix xdp_sample_user.o linking with Clang Alexander Lobakin
@ 2021-12-03 19:50 ` Alexander Lobakin
2021-12-04 0:47 ` Kumar Kartikeya Dwivedi
2021-12-07 3:35 ` [PATCH bpf 0/2] samples: bpf: fix build issues with Clang/LLVM Andrii Nakryiko
2 siblings, 1 reply; 6+ messages in thread
From: Alexander Lobakin @ 2021-12-03 19:50 UTC (permalink / raw)
To: Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko
Cc: Alexander Lobakin, Toke Høiland-Jørgensen,
Kumar Kartikeya Dwivedi, John Fastabend, Jesper Dangaard Brouer,
Nathan Chancellor, Nick Desaulniers, netdev, bpf, linux-kernel,
llvm
Clang doesn't have 'stringop-truncation' group like GCC does, and
complains about it when building samples which use xdp_sample_user
infra:
samples/bpf/xdp_sample_user.h:48:32: warning: unknown warning group '-Wstringop-truncation', ignored [-Wunknown-warning-option]
#pragma GCC diagnostic ignored "-Wstringop-truncation"
^
[ repeat ]
Those are harmless, but avoidable when guarding it with ifdef.
I could guard push/pop as well, but this would require one more
ifdef cruft around a single line which I don't think is reasonable.
Fixes: 156f886cf697 ("samples: bpf: Add basic infrastructure for XDP samples")
Signed-off-by: Alexander Lobakin <alexandr.lobakin@intel.com>
---
samples/bpf/xdp_sample_user.h | 2 ++
1 file changed, 2 insertions(+)
diff --git a/samples/bpf/xdp_sample_user.h b/samples/bpf/xdp_sample_user.h
index d97465ff8c62..5f44b877ecf5 100644
--- a/samples/bpf/xdp_sample_user.h
+++ b/samples/bpf/xdp_sample_user.h
@@ -45,7 +45,9 @@ const char *get_driver_name(int ifindex);
int get_mac_addr(int ifindex, void *mac_addr);
#pragma GCC diagnostic push
+#ifndef __clang__
#pragma GCC diagnostic ignored "-Wstringop-truncation"
+#endif
__attribute__((unused))
static inline char *safe_strncpy(char *dst, const char *src, size_t size)
{
--
2.33.1
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH bpf 2/2] samples: bpf: fix 'unknown warning group' build warning on Clang
2021-12-03 19:50 ` [PATCH bpf 2/2] samples: bpf: fix 'unknown warning group' build warning on Clang Alexander Lobakin
@ 2021-12-04 0:47 ` Kumar Kartikeya Dwivedi
0 siblings, 0 replies; 6+ messages in thread
From: Kumar Kartikeya Dwivedi @ 2021-12-04 0:47 UTC (permalink / raw)
To: Alexander Lobakin
Cc: Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko,
Toke Høiland-Jørgensen, John Fastabend,
Jesper Dangaard Brouer, Nathan Chancellor, Nick Desaulniers,
netdev, bpf, linux-kernel, llvm
On Sat, Dec 04, 2021 at 01:20:04AM IST, Alexander Lobakin wrote:
> Clang doesn't have 'stringop-truncation' group like GCC does, and
> complains about it when building samples which use xdp_sample_user
> infra:
>
> samples/bpf/xdp_sample_user.h:48:32: warning: unknown warning group '-Wstringop-truncation', ignored [-Wunknown-warning-option]
> #pragma GCC diagnostic ignored "-Wstringop-truncation"
> ^
> [ repeat ]
>
> Those are harmless, but avoidable when guarding it with ifdef.
> I could guard push/pop as well, but this would require one more
> ifdef cruft around a single line which I don't think is reasonable.
>
> Fixes: 156f886cf697 ("samples: bpf: Add basic infrastructure for XDP samples")
> Signed-off-by: Alexander Lobakin <alexandr.lobakin@intel.com>
> ---
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
> [...]
--
Kartikeya
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH bpf 0/2] samples: bpf: fix build issues with Clang/LLVM
2021-12-03 19:50 [PATCH bpf 0/2] samples: bpf: fix build issues with Clang/LLVM Alexander Lobakin
2021-12-03 19:50 ` [PATCH bpf 1/2] samples: bpf: fix xdp_sample_user.o linking with Clang Alexander Lobakin
2021-12-03 19:50 ` [PATCH bpf 2/2] samples: bpf: fix 'unknown warning group' build warning on Clang Alexander Lobakin
@ 2021-12-07 3:35 ` Andrii Nakryiko
2 siblings, 0 replies; 6+ messages in thread
From: Andrii Nakryiko @ 2021-12-07 3:35 UTC (permalink / raw)
To: Alexander Lobakin
Cc: Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko,
Toke Høiland-Jørgensen, Kumar Kartikeya Dwivedi,
John Fastabend, Jesper Dangaard Brouer, Nathan Chancellor,
Nick Desaulniers, Networking, bpf, open list, llvm
On Fri, Dec 3, 2021 at 11:55 AM Alexander Lobakin
<alexandr.lobakin@intel.com> wrote:
>
> Samples, at least XDP ones, can be built only with the compiler used
> to build the kernel itself.
> However, XDP sample infra introduced in Aug'21 was probably tested
> with GCC/Binutils only as it's not really compilable for now with
> Clang/LLVM.
> These two are trivial fixes addressing this.
>
> Alexander Lobakin (2):
> samples: bpf: fix xdp_sample_user.o linking with Clang
> samples: bpf: fix 'unknown warning group' build warning on Clang
>
There were conflicts when applying, but luckily I was the one who
caused this conflict in XDP_SAMPLE_CFLAGS, so I just fixed it up
locally and pushed to bpf-next. Thanks.
> samples/bpf/Makefile | 5 +++++
> samples/bpf/Makefile.target | 2 +-
> samples/bpf/xdp_sample_user.h | 2 ++
> 3 files changed, 8 insertions(+), 1 deletion(-)
>
> --
> 2.33.1
>
^ permalink raw reply [flat|nested] 6+ messages in thread