From: Arnaldo Carvalho de Melo <[email protected]>
When the loop body isn't executed at all, then the 'ret' local variable,
that is uninitialized will be used as the return value.
This triggers this error on Alpine Linux:
CC /tmp/build/perf/util/demangle-java.o
CC /tmp/build/perf/util/demangle-rust.o
CC /tmp/build/perf/util/jitdump.o
CC /tmp/build/perf/util/genelf.o
util/jitdump.c: In function 'jit_process':
util/jitdump.c:622:3: error: 'ret' may be used uninitialized in this function
[-Werror=maybe-uninitialized]
fprintf(stderr, "injected: %s (%d)\n", path, ret);
^
util/jitdump.c:584:6: note: 'ret' was declared here
int ret;
^
FLEX /tmp/build/perf/util/parse-events-flex.c
/ $ gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-alpine-linux-musl/5.3.0/lto-wrapper
Target: x86_64-alpine-linux-musl
Configured with: /home/buildozer/aports/main/gcc/src/gcc-5.3.0/configure
--prefix=/usr --mandir=/usr/share/man --infodir=/usr/share/info
+--build=x86_64-alpine-linux-musl --host=x86_64-alpine-linux-musl
--target=x86_64-alpine-linux-musl --with-pkgversion='Alpine 5.3.0'
--enable-checking=release
+--disable-fixed-point --disable-libstdcxx-pch --disable-multilib
--disable-nls --disable-werror --disable-symvers --enable-__cxa_atexit
--enable-esp
+--enable-cloog-backend --enable-languages=c,c++,objc,java,fortran,ada
--disable-libssp --disable-libmudflap --disable-libsanitizer --enable-shared
+--enable-threads --enable-tls --with-system-zlib
Thread model: posix
gcc version 5.3.0 (Alpine 5.3.0)
But this so far got under the radar, not causing any build problem, till the
"perf jit: enable jitdump support without dwarf" gets applied, when the above
problem takes place, some combination of inlining or whatever, the problem
is real, so fix it by initializing the variable to zero.
Cc: Anton Blanchard <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Maciej Debski <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Stephane Eranian <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
---
tools/perf/util/jitdump.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/perf/util/jitdump.c b/tools/perf/util/jitdump.c
index 95f0884aae02..f3ed3c963c71 100644
--- a/tools/perf/util/jitdump.c
+++ b/tools/perf/util/jitdump.c
@@ -581,7 +581,7 @@ static int
jit_process_dump(struct jit_buf_desc *jd)
{
union jr_entry *jr;
- int ret;
+ int ret = 0;
while ((jr = jit_get_next_entry(jd))) {
switch(jr->prefix.id) {
--
2.7.4
