Re: [PATCH] perf/test: perf test 86 fails on s390 repo linux-next

[Namhyung Kim <namhyung@kernel.org>]

Hello,

On Mon, Sep 16, 2024 at 02:57:18PM +0200, Thomas Richter wrote:
> Command perf test 86 fails on s390 using linux-next repository:
>  # perf test -F 86
>  ping 868299 [007] 28248.013596: probe_libc:inet_pton_1: (3ff95948020)
>  3ff95948020 inet_pton+0x0 (inlined)
>  3ff9595e6e7 text_to_binary_address+0x1007 (inlined)
>  3ff9595e6e7 gaih_inet+0x1007 (inlined)
>  FAIL: expected backtrace entry \
> 	 "main\+0x[[:xdigit:]]+[[:space:]]\(.*/bin/ping.*\)$"
> 	 got "3ff9595e6e7 gaih_inet+0x1007 (inlined)"
>  86: probe libc's inet_pton & backtrace it with ping  : FAILED!
>  #
> 
> The root cause is a new stack layout, some functions have been added
> as seen below. Add text_to_binary_address and friends to the
> list of expected functions.
> 
>  # perf script | tac | grep -m1 '^ping' -B9 | tac
>  ping  866856 [007] 25979.494921: probe_libc:inet_pton: (3ff8ec48020)
> 	     3ff8ec48020 inet_pton+0x0 (inlined)
> 	     3ff8ec5e6e7 text_to_binary_address+0x1007 (inlined)
> 	     3ff8ec5e6e7 gaih_inet+0x1007 (inlined)
> 	     3ff8ec5e6e7 getaddrinfo+0x1007 (/usr/lib64/libc.so.6)
> 	     2aa3fe04bf5 main+0xff5 (/usr/bin/ping)
> 	     3ff8eb34a5b __libc_start_call_main+0x8b (/usr/lib64/libc.so.6)
> 	     3ff8eb34b5d __libc_start_main@GLIBC_2.2+0xad (inlined)
> 	     2aa3fe06a1f [unknown] (/usr/bin/ping)

Is it because of a kernel change?  What about old kernels then?

> 
>  #
> 
> Output after:
>  # perf test -F 86
>  86: probe libc's inet_pton & backtrace it with ping  : Ok
>  #
> 
> Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
> ---
>  tools/perf/tests/shell/record+probe_libc_inet_pton.sh | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/tools/perf/tests/shell/record+probe_libc_inet_pton.sh b/tools/perf/tests/shell/record+probe_libc_inet_pton.sh
> index f38c8ead0b03..bc6e2fe1d999 100755
> --- a/tools/perf/tests/shell/record+probe_libc_inet_pton.sh
> +++ b/tools/perf/tests/shell/record+probe_libc_inet_pton.sh
> @@ -40,6 +40,8 @@ trace_libc_inet_pton_backtrace() {
>  	case "$(uname -m)" in
>  	s390x)
>  		eventattr='call-graph=dwarf,max-stack=4'
> +		echo "text_to_binary_address\+0x[[:xdigit:]]+[[:space:]]\($libc|inlined\)$" >> $expected
> +		echo "gaih_inet\+0x[[:xdigit:]]+[[:space:]]\($libc|inlined\)$" >> $expected

Is it possible to make it this part conditional and only have it for the
new kernels?

Thanks,
Namhyung


>  		echo "(__GI_)?getaddrinfo\+0x[[:xdigit:]]+[[:space:]]\($libc|inlined\)$" >> $expected
>  		echo "main\+0x[[:xdigit:]]+[[:space:]]\(.*/bin/ping.*\)$" >> $expected
>  		;;
> -- 
> 2.46.0
>