From: Thomas Richter <tmricht@linux.ibm.com>
To: "linux-perf-use." <linux-perf-users@vger.kernel.org>,
Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>, Heiko Carstens <hca@linux.ibm.com>
Subject: perf test case probe libc fails with latest Fedora34 glibc update
Date: Wed, 23 Jun 2021 16:21:17 +0200 [thread overview]
Message-ID: <cae863a4-bf83-f87b-6e71-b6a544678cae@linux.ibm.com> (raw)
I just updated Fedora34 to the latest level and discovered that perf test 78 fails:
[root@m46lp22 perf]# ./perf test 78
78: probe libc's inet_pton & backtrace it with ping : FAILED!
[root@m46lp22 perf]#
It boils down to this command and happens after glibc is update to level 2.33-18.
[root@f34 ~]# perf probe -f -x /usr/lib64/libc-2.33.so -a inet_pton
Probe point 'inet_pton' not found.
Error: Failed to add events.
[root@f34 ~]# rpm -qa | fgrep glibc
glibc-all-langpacks-2.33-18.fc34.x86_64
glibc-common-2.33-18.fc34.x86_64
glibc-langpack-en-2.33-18.fc34.x86_64
glibc-2.33-18.fc34.x86_64
glibc-doc-2.33-18.fc34.noarch
glibc-headers-x86-2.33-18.fc34.noarch
glibc-devel-2.33-18.fc34.x86_64
glibc-debugsource-2.33-18.fc34.x86_64
glibc-debuginfo-2.33-18.fc34.x86_64
[root@f34 ~]#
The symbol inet_pton is now in the .dynsym section of glibc:
[root@f34 ~]# readelf -sW /usr/lib64/libc-2.33.so | egrep '(dynsym|symtab|inet_pton)'
Symbol table '.dynsym' contains 2419 entries:
628: 000000000011ea00 108 FUNC WEAK DEFAULT 15 inet_pton@@GLIBC_2.2.5
2251: 000000000011e9b0 76 FUNC GLOBAL DEFAULT 15 __inet_pton_length@@GLIBC_PRIVATE
Symbol table '.symtab' contains 104 entries:
[root@f34 ~]#
The .symtab section does not contain symbol inet_pton. It contains very few symbols
compared to previous versions.
Now perf does not find it. In the older version of the library the
symbol inet_pton was listed in the .symtab section. Here is the output from version 2.32-4:
[root@m35lp76 ~]# rpm -qa | fgrep glibc
glibc-common-2.32-4.fc33.s390x
glibc-langpack-en-2.32-4.fc33.s390x
glibc-2.32-4.fc33.s390x
glibc-headers-s390-2.32-4.fc33.noarch
glibc-devel-2.32-4.fc33.s390x
glibc-debuginfo-common-2.32-4.fc33.s390x
glibc-debuginfo-2.32-4.fc33.s390x
[root@m35lp76 ~]#
readelf -sW /usr/lib64/libc-2.32.so | egrep '(dynsym|symtab|inet_pton)'
Symbol table '.dynsym' contains 2604 entries:
668: 00000000001444b0 788 FUNC WEAK DEFAULT 13 inet_pton@@GLIBC_2.2
2418: 00000000001441b0 764 FUNC GLOBAL DEFAULT 13 __inet_pton_length@@GLIBC_PRIVATE
Symbol table '.symtab' contains 28858 entries:
20655: 0000000000000000 0 FILE LOCAL DEFAULT ABS inet_pton.c
20656: 00000000001440b0 0 NOTYPE LOCAL HIDDEN 13 .annobin_inet_pton.c
20657: 00000000001447c4 0 NOTYPE LOCAL HIDDEN 13 .annobin_inet_pton.c_end
20658: 000000000002ba70 0 NOTYPE LOCAL HIDDEN 13 .annobin_inet_pton.c.hot
20659: 000000000002ba70 0 NOTYPE LOCAL HIDDEN 13 .annobin_inet_pton.c_end.hot
20660: 000000000002b938 0 NOTYPE LOCAL HIDDEN 13 .annobin_inet_pton.c.unlikely
20661: 000000000002b938 0 NOTYPE LOCAL HIDDEN 13 .annobin_inet_pton.c_end.unlikely
20662: 000000000002ba70 0 NOTYPE LOCAL HIDDEN 13 .annobin_inet_pton.c.startup
20663: 000000000002ba70 0 NOTYPE LOCAL HIDDEN 13 .annobin_inet_pton.c_end.startup
20664: 000000000002b968 0 NOTYPE LOCAL HIDDEN 13 .annobin_inet_pton.c.exit
20665: 000000000002b968 0 NOTYPE LOCAL HIDDEN 13 .annobin_inet_pton.c_end.exit
20666: 00000000001440b0 0 NOTYPE LOCAL HIDDEN 13 .annobin_inet_pton4.start
20667: 00000000001441aa 0 NOTYPE LOCAL HIDDEN 13 .annobin_inet_pton4.end
20668: 00000000001440b0 250 FUNC LOCAL DEFAULT 13 inet_pton4
20669: 00000000001441aa 0 NOTYPE LOCAL HIDDEN 13 .annobin___GI___inet_pton_length.start
20670: 00000000001444ac 0 NOTYPE LOCAL HIDDEN 13 .annobin___GI___inet_pton_length.end
20671: 00000000001444ac 0 NOTYPE LOCAL HIDDEN 13 .annobin___GI___inet_pton.start
20672: 00000000001447c4 0 NOTYPE LOCAL HIDDEN 13 .annobin___GI___inet_pton.end
23591: 00000000001441b0 764 FUNC LOCAL DEFAULT 13 __GI___inet_pton_length
23871: 00000000001444b0 788 FUNC LOCAL DEFAULT 13 __inet_pton
24506: 00000000001444b0 788 FUNC LOCAL DEFAULT 13 __GI___inet_pton
25831: 00000000001444b0 788 FUNC LOCAL DEFAULT 13 __GI_inet_pton
26410: 00000000001441b0 764 FUNC GLOBAL DEFAULT 13 __inet_pton_length
27288: 00000000001444b0 788 FUNC WEAK DEFAULT 13 inet_pton
[root@m35lp76 ~]#
And perf could find the symbol, extract its address and install a probe
on that address.
So is this a bug related to the perf tool because it can not handle .dynsym section?
Or is it releated to glibc's rework?
Thanks for your help.
--
Thomas Richter, Dept 3303, IBM s390 Linux Development, Boeblingen, Germany
--
Vorsitzender des Aufsichtsrats: Gregor Pillen
Geschäftsführung: Dirk Wittkopp
Sitz der Gesellschaft: Böblingen / Registergericht: Amtsgericht Stuttgart, HRB 243294
next reply other threads:[~2021-06-23 14:21 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-23 14:21 Thomas Richter [this message]
2021-06-25 10:34 ` perf test case probe libc fails with latest Fedora34 glibc update Jiri Olsa
2021-06-25 10:57 ` Thomas Richter
2021-06-25 10:43 ` Part 2: " Thomas Richter
2021-06-29 5:02 ` Masami Hiramatsu
2021-06-29 6:42 ` Thomas Richter
2021-06-29 14:06 ` Masami Hiramatsu
2021-06-30 16:02 ` Masami Hiramatsu
2021-07-02 0:41 ` Masami Hiramatsu
2021-06-29 7:21 ` perf test case probe libc fails with latest Fedora34 glibc update, more info Thomas Richter
2021-06-29 14:01 ` Masami Hiramatsu
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