From: Jiri Olsa jolsa@kernel.org
[ Upstream commit 1934adf78e33fa69570a763c7ac5353212416bb0 ]
We currently fail the MMAP event processing if we don't have the MMAP event's specific arch unwind support compiled in.
That's wrong and can lead to unresolved mmaps in report output for 32bit binaries on 64bit server, like in this example on x86_64 server:
$ cat ex.c int main(int argc, char **argv) { while (1) {} } $ gcc -o ex -m32 ex.c $ perf record ./ex ^C[ perf record: Woken up 2 times to write data ] [ perf record: Captured and wrote 0.371 MB perf.data (9322 samples) ]
Before: $ perf report --stdio
SNIP
# Overhead Command Shared Object Symbol # ........ ....... ................ ...................... # 100.00% ex [unknown] [.] 0x00000000080483de 0.00% ex [unknown] [.] 0x00000000f76dba4f 0.00% ex [unknown] [.] 0x00000000f76e4c11 0.00% ex [unknown] [.] 0x00000000f76daa30
After: $ perf report --stdio
SNIP
# Overhead Command Shared Object Symbol # ........ ....... ............. ............... # 100.00% ex ex [.] main 0.00% ex ld-2.24.so [.] _dl_start 0.00% ex ld-2.24.so [.] do_lookup_x 0.00% ex ld-2.24.so [.] _start
The fix is not to fail, just warn if there's not unwind support compiled in.
Reported-by: Michael Lyle mlyle@lyle.org Signed-off-by: Jiri Olsa jolsa@kernel.org Tested-by: Arnaldo Carvalho de Melo acme@redhat.com Cc: David Ahern dsahern@gmail.com Cc: He Kuang hekuang@huawei.com Cc: Namhyung Kim namhyung@kernel.org Cc: Peter Zijlstra a.p.zijlstra@chello.nl Link: http://lkml.kernel.org/r/20170704131131.27508-1-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo acme@redhat.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com --- tools/perf/util/unwind-libunwind.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/perf/util/unwind-libunwind.c b/tools/perf/util/unwind-libunwind.c index 6d542a4e0648..8aef572d0889 100644 --- a/tools/perf/util/unwind-libunwind.c +++ b/tools/perf/util/unwind-libunwind.c @@ -50,7 +50,7 @@ int unwind__prepare_access(struct thread *thread, struct map *map,
if (!ops) { pr_err("unwind: target platform=%s is not supported\n", arch); - return -1; + return 0; } out_register: unwind__register_ops(thread, ops);