b31a8cc1a5
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: 3d20c6246690 ("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.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.