Em Mon, Apr 23, 2018 at 10:24:28AM +0200, Thomas Richter escreveu:
> 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
> 3d20c6246690219881786de10d2dda93f616d0ac
> ("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:
Thanks, applied.
