From 3168c158ad3535af1cd7423c9f8cd5ac549f2f9c Mon Sep 17 00:00:00 2001 From: Tony Ambardar Date: Sun, 30 Aug 2020 17:03:04 -0700 Subject: libbpf: Fix build failure from uninitialized variable warning While compiling libbpf, some GCC versions (at least 8.4.0) have difficulty determining control flow and a emit warning for potentially uninitialized usage of 'map', which results in a build error if using "-Werror": In file included from libbpf.c:56: libbpf.c: In function '__bpf_object__open': libbpf_internal.h:59:2: warning: 'map' may be used uninitialized in this function [-Wmaybe-uninitialized] libbpf_print(level, "libbpf: " fmt, ##__VA_ARGS__); \ ^~~~~~~~~~~~ libbpf.c:5032:18: note: 'map' was declared here struct bpf_map *map, *targ_map; ^~~ The warning/error is false based on code inspection, so silence it with a NULL initialization. Fixes: 646f02ffdd49 ("libbpf: Add BTF-defined map-in-map support") Reference: 063e68813391 ("libbpf: Fix false uninitialized variable warning") Signed-off-by: Tony Ambardar Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20200831000304.1696435-1-Tony.Ambardar@gmail.com --- tools/lib/bpf/libbpf.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 0ad0b0491e1f..7253b833576c 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -5203,8 +5203,8 @@ static int bpf_object__collect_map_relos(struct bpf_object *obj, int i, j, nrels, new_sz; const struct btf_var_secinfo *vi = NULL; const struct btf_type *sec, *var, *def; + struct bpf_map *map = NULL, *targ_map; const struct btf_member *member; - struct bpf_map *map, *targ_map; const char *name, *mname; Elf_Data *symbols; unsigned int moff; -- cgit v1.2.3 From 21e9ba5373fc2cec608fd68301a1dbfd14df3172 Mon Sep 17 00:00:00 2001 From: "Naveen N. Rao" Date: Wed, 2 Sep 2020 14:12:46 +0530 Subject: libbpf: Remove arch-specific include path in Makefile Ubuntu mainline builds for ppc64le are failing with the below error (*): CALL /home/kernel/COD/linux/scripts/atomic/check-atomics.sh DESCEND bpf/resolve_btfids Auto-detecting system features: ... libelf: [ [32mon[m ] ... zlib: [ [32mon[m ] ... bpf: [ [31mOFF[m ] BPF API too old make[6]: *** [Makefile:295: bpfdep] Error 1 make[5]: *** [Makefile:54: /home/kernel/COD/linux/debian/build/build-generic/tools/bpf/resolve_btfids//libbpf.a] Error 2 make[4]: *** [Makefile:71: bpf/resolve_btfids] Error 2 make[3]: *** [/home/kernel/COD/linux/Makefile:1890: tools/bpf/resolve_btfids] Error 2 make[2]: *** [/home/kernel/COD/linux/Makefile:335: __build_one_by_one] Error 2 make[2]: Leaving directory '/home/kernel/COD/linux/debian/build/build-generic' make[1]: *** [Makefile:185: __sub-make] Error 2 make[1]: Leaving directory '/home/kernel/COD/linux' resolve_btfids needs to be build as a host binary and it needs libbpf. However, libbpf Makefile hardcodes an include path utilizing $(ARCH). This results in mixing of cross-architecture headers resulting in a build failure. The specific header include path doesn't seem necessary for a libbpf build. Hence, remove the same. (*) https://kernel.ubuntu.com/~kernel-ppa/mainline/v5.9-rc3/ppc64el/log Reported-by: Vaidyanathan Srinivasan Signed-off-by: Naveen N. Rao Signed-off-by: Daniel Borkmann Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20200902084246.1513055-1-naveen.n.rao@linux.vnet.ibm.com --- tools/lib/bpf/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile index bf8ed134cb8a..b78484e7a608 100644 --- a/tools/lib/bpf/Makefile +++ b/tools/lib/bpf/Makefile @@ -59,7 +59,7 @@ FEATURE_USER = .libbpf FEATURE_TESTS = libelf libelf-mmap zlib bpf reallocarray FEATURE_DISPLAY = libelf zlib bpf -INCLUDES = -I. -I$(srctree)/tools/include -I$(srctree)/tools/arch/$(ARCH)/include/uapi -I$(srctree)/tools/include/uapi +INCLUDES = -I. -I$(srctree)/tools/include -I$(srctree)/tools/include/uapi FEATURE_CHECK_CFLAGS-bpf = $(INCLUDES) check_feat := 1 -- cgit v1.2.3 From 746f534a4809e07f427f7d13d10f3a6a9641e5c3 Mon Sep 17 00:00:00 2001 From: Tony Ambardar Date: Sat, 5 Sep 2020 14:48:31 -0700 Subject: tools/libbpf: Avoid counting local symbols in ABI check Encountered the following failure building libbpf from kernel 5.8.5 sources with GCC 8.4.0 and binutils 2.34: (long paths shortened) Warning: Num of global symbols in sharedobjs/libbpf-in.o (234) does NOT match with num of versioned symbols in libbpf.so (236). Please make sure all LIBBPF_API symbols are versioned in libbpf.map. --- libbpf_global_syms.tmp 2020-09-02 07:30:58.920084380 +0000 +++ libbpf_versioned_syms.tmp 2020-09-02 07:30:58.924084388 +0000 @@ -1,3 +1,5 @@ +_fini +_init bpf_btf_get_fd_by_id bpf_btf_get_next_id bpf_create_map make[4]: *** [Makefile:210: check_abi] Error 1 Investigation shows _fini and _init are actually local symbols counted amongst global ones: $ readelf --dyn-syms --wide libbpf.so|head -10 Symbol table '.dynsym' contains 343 entries: Num: Value Size Type Bind Vis Ndx Name 0: 00000000 0 NOTYPE LOCAL DEFAULT UND 1: 00004098 0 SECTION LOCAL DEFAULT 11 2: 00004098 8 FUNC LOCAL DEFAULT 11 _init@@LIBBPF_0.0.1 3: 00023040 8 FUNC LOCAL DEFAULT 14 _fini@@LIBBPF_0.0.1 4: 00000000 0 OBJECT GLOBAL DEFAULT ABS LIBBPF_0.0.4 5: 00000000 0 OBJECT GLOBAL DEFAULT ABS LIBBPF_0.0.1 6: 0000ffa4 8 FUNC GLOBAL DEFAULT 12 bpf_object__find_map_by_offset@@LIBBPF_0.0.1 A previous commit filtered global symbols in sharedobjs/libbpf-in.o. Do the same with the libbpf.so DSO for consistent comparison. Fixes: 306b267cb3c4 ("libbpf: Verify versioned symbols") Signed-off-by: Tony Ambardar Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20200905214831.1565465-1-Tony.Ambardar@gmail.com --- tools/lib/bpf/Makefile | 2 ++ 1 file changed, 2 insertions(+) (limited to 'tools/lib') diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile index b78484e7a608..9ae8f4ef0aac 100644 --- a/tools/lib/bpf/Makefile +++ b/tools/lib/bpf/Makefile @@ -152,6 +152,7 @@ GLOBAL_SYM_COUNT = $(shell readelf -s --wide $(BPF_IN_SHARED) | \ awk '/GLOBAL/ && /DEFAULT/ && !/UND/ {print $$NF}' | \ sort -u | wc -l) VERSIONED_SYM_COUNT = $(shell readelf --dyn-syms --wide $(OUTPUT)libbpf.so | \ + awk '/GLOBAL/ && /DEFAULT/ && !/UND/ {print $$NF}' | \ grep -Eo '[^ ]+@LIBBPF_' | cut -d@ -f1 | sort -u | wc -l) CMD_TARGETS = $(LIB_TARGET) $(PC_FILE) @@ -219,6 +220,7 @@ check_abi: $(OUTPUT)libbpf.so awk '/GLOBAL/ && /DEFAULT/ && !/UND/ {print $$NF}'| \ sort -u > $(OUTPUT)libbpf_global_syms.tmp; \ readelf --dyn-syms --wide $(OUTPUT)libbpf.so | \ + awk '/GLOBAL/ && /DEFAULT/ && !/UND/ {print $$NF}'| \ grep -Eo '[^ ]+@LIBBPF_' | cut -d@ -f1 | \ sort -u > $(OUTPUT)libbpf_versioned_syms.tmp; \ diff -u $(OUTPUT)libbpf_global_syms.tmp \ -- cgit v1.2.3