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| author |   Thomas Richter <tmricht@linux.ibm.com> | 2018-07-27 10:21:26 +0200 |
|---|---|---|
| committer |   Daniel Borkmann <daniel@iogearbox.net> | 2018-07-28 21:22:40 +0200 |
| commit | b611da43b68193dcb7e632adb44d506374a5d3ef (patch) | |
| tree | d3cb705767d6f8374fd1d80aefc39f7a4d4dc661 /tools/lib/bpf/libbpf.c | |
| parent | bpf: btf: Use exact btf value_size match in map_check_btf() (diff) | |
| download | linux-dev-b611da43b68193dcb7e632adb44d506374a5d3ef.tar.xz linux-dev-b611da43b68193dcb7e632adb44d506374a5d3ef.zip | |
perf build: Build error in libbpf missing initialization
In linux-next tree compiling the perf tool with additional make flags
EXTRA_CFLAGS="-Wp,-D_FORTIFY_SOURCE=2 -O2" causes a compiler error.
It is the warning 'variable may be used uninitialized' which is treated
as error: I compile it using a FEDORA 28 installation, my gcc compiler
version: gcc (GCC) 8.0.1 20180324 (Red Hat 8.0.1-0.20). The file that
causes the error is tools/lib/bpf/libbpf.c.
[root@p23lp27] # make V=1 EXTRA_CFLAGS="-Wp,-D_FORTIFY_SOURCE=2 -O2"
[...]
Makefile.config:849: No openjdk development package found, please
install JDK package, e.g. openjdk-8-jdk, java-1.8.0-openjdk-devel
Warning: Kernel ABI header at 'tools/include/uapi/linux/if_link.h'
differs from latest version at 'include/uapi/linux/if_link.h'
CC libbpf.o
libbpf.c: In function ‘bpf_perf_event_read_simple’:
libbpf.c:2342:6: error: ‘ret’ may be used uninitialized in this
function [-Werror=maybe-uninitialized]
int ret;
^
cc1: all warnings being treated as errors
mv: cannot stat './.libbpf.o.tmp': No such file or directory
/home6/tmricht/linux-next/tools/build/Makefile.build:96: recipe for target 'libbpf.o' failed
Suggested-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Diffstat (limited to 'tools/lib/bpf/libbpf.c')
| -rw-r--r-- | tools/lib/bpf/libbpf.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index d881d370616c..1aafdbe827fe 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -2273,8 +2273,8 @@ bpf_perf_event_read_simple(void *mem, unsigned long size, volatile struct perf_event_mmap_page *header = mem; __u64 data_tail = header->data_tail; __u64 data_head = header->data_head; + int ret = LIBBPF_PERF_EVENT_ERROR; void *base, *begin, *end; - int ret; asm volatile("" ::: "memory"); /* in real code it should be smp_rmb() */ if (data_head == data_tail) |