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Thomas Richter authored
perf test case 58 (record+probe_libc_inet_pton.sh) executed on s390x using kernel 4.16.0rc3 displays this result: # perf trace --no-syscalls -e probe_libc:inet_pton/call-graph=dwarf/ ping -6 -c 1 ::1 probe_libc:inet_pton: (3ffa0240448) __GI___inet_pton (/usr/lib64/libc-2.26.so) gaih_inet (inlined) __GI_getaddrinfo (inlined) main (/usr/bin/ping) __libc_start_main (/usr/lib64/libc-2.26.so) _start (/usr/bin/ping) After I installed kernel 4.16.0 the same tests uses commands: # perf record -e probe_libc:inet_pton/call-graph=dwarf/ -o /tmp/perf.data.abc ping -6 -c 1 ::1 # perf script -i /tmp/perf.data.abc and displays: ping 39048 [006] 84230.381198: probe_libc:inet_pton: (3ffa0240448) 140448 __GI___inet_pton (/usr/lib64/libc-2.26.so) fbde1 gaih_inet (inlined) fe2b9 __GI_getaddrinfo (inlined) 398d main (/usr/bin/ping) Nothing else changed including glibc elfutils and other libraries picked up by the build. The entries for __libc_start_main and _start are missing. I bisected missing __libc_start_main and _start to commit Fixes: 3d20c624 ("perf unwind: Unwind with libdw doesn't take symfs into account") When I undo this commit I get this call stack on s390: [root@s35lp76 perf]# ./perf script -i /tmp/perf.data.abc ping 39048 [006] 84230.381198: probe_libc:inet_pton: (3ffa0240448) 140448 __GI___inet_pton (/usr/lib64/libc-2.26.so) fbde1 gaih_inet (inlined) fe2b9 __GI_getaddrinfo (inlined) 398d main (/usr/bin/ping) 22fbd __libc_start_main (/usr/lib64/libc-2.26.so) 457b _start (/usr/bin/ping) Looks like dwarf functions dwfl_xxx create different call back stack trace when using file /usr/lib/debug/usr/bin/ping-20161105-7.fc27.s390x.debug instead of file /usr/bin/ping. Fix this test case on s390 and do not expect any call back stack entry after the main() function. Also be more robust and accept a leading __GI_ prefix in front of getaddrinfo. On x86 this test case shows the same call stack using both kernel versions 4.16.0rc3 and 4.16.0 and also stops at main: [root@f27 perf]# ./perf script -i /tmp/perf.data.tmr ping 4446 [000] 172.027088: probe_libc:inet_pton: (7fdfa08c93c0) 1393c0 __GI___inet_pton (/usr/lib64/libc-2.26.so) fe60d getaddrinfo (/usr/lib64/libc-2.26.so) 2f40 main (/usr/bin/ping) [root@f27 perf]# Signed-off-by:
Thomas Richter <tmricht@linux.ibm.com> Reviewed-by:
Hendrik Brueckner <brueckner@linux.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Martin Vuille <jpmv27@aim.com> Link: http://lkml.kernel.org/r/20180423082428.7930-1-tmricht@linux.ibm.comSigned-off-by:
Arnaldo Carvalho de Melo <acme@redhat.com>
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