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The "perf test Session topology" entry fails with core dump on s390. The root
cause is a NULL pointer dereference in function check_cpu_topology() line 76
(or line 82 without -v).
The session->header.env.cpu variable is NULL because on s390 function
process_cpu_topology() returns with error:
socket_id number is too big.
You may need to upgrade the perf tool.
and releases the env.cpu variable via zfree() and sets it to NULL.
Here is the gdb output:
(gdb) n
76 pr_debug("CPU %d, core %d, socket %d\n", i,
(gdb) n
Program received signal SIGSEGV, Segmentation fault.
0x00000000010f4d9e in check_cpu_topology (path=0x3ffffffd6c8
"/tmp/perf-test-J6CHMa", map=0x14a1740) at tests/topology.c:76
76 pr_debug("CPU %d, core %d, socket %d\n", i,
(gdb)
Make sure the env.cpu variable is not used when its NULL.
Test for NULL pointer and return TEST_SKIP if so.
Output before:
[root@p23lp27 perf]# ./perf test -F 39
39: Session topology :Segmentation fault (core dumped)
[root@p23lp27 perf]#
Output after:
[root@p23lp27 perf]# ./perf test -vF 39
39: Session topology :
--- start ---
templ file: /tmp/perf-test-Ajx59D
socket_id number is too big.You may need to upgrade the perf tool.
---- end ----
Session topology: Skip
[root@p23lp27 perf]#
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Link: http://lkml.kernel.org/r/20180528073657.11743-1-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.