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For some cases, the callchain provided by the kernel may be empty. So,
the callchain ip filtering code will cause a crash if we do not check
whether the struct ip_callchain pointer is NULL before accessing any
members.
This can be observed on a powerpc64le system running Fedora 27 as shown
below.
# perf record -b -e cycles:u ls
Before:
# perf report --branch-history
perf: Segmentation fault
-------- backtrace --------
perf[0x1027615c]
linux-vdso64.so.1(__kernel_sigtramp_rt64+0x0)[0x7fff856304d8]
perf(arch_skip_callchain_idx+0x44)[0x10257c58]
perf[0x1017f2e4]
perf(thread__resolve_callchain+0x124)[0x1017ff5c]
perf(sample__resolve_callchain+0xf0)[0x10172788]
...
After:
# perf report --branch-history
Samples: 25 of event 'cycles:u', Event count (approx.): 2306870
Overhead Source:Line Symbol Shared Object
+ 11.60% _init+35736 [.] _init ls
+ 9.84% strcoll_l.c:137 [.] __strcoll_l libc-2.26.so
+ 9.16% memcpy.S:175 [.] __memcpy_power7 libc-2.26.so
+ 9.01% gconv_charset.h:54 [.] _nl_find_locale libc-2.26.so
+ 8.87% dl-addr.c:52 [.] _dl_addr libc-2.26.so
+ 8.83% _init+236 [.] _init ls
...
Reported-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Signed-off-by: Sandipan Das <sandipan@linux.ibm.com>
Acked-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/20180611104049.11048-1-sandipan@linux.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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| .. | ||
| arch | ||
| bench | ||
| Documentation | ||
| examples/bpf | ||
| include/bpf | ||
| jvmti | ||
| pmu-events | ||
| python | ||
| scripts | ||
| tests | ||
| trace | ||
| ui | ||
| util | ||
| .gitignore | ||
| Build | ||
| builtin-annotate.c | ||
| builtin-bench.c | ||
| builtin-buildid-cache.c | ||
| builtin-buildid-list.c | ||
| builtin-c2c.c | ||
| builtin-config.c | ||
| builtin-data.c | ||
| builtin-diff.c | ||
| builtin-evlist.c | ||
| builtin-ftrace.c | ||
| builtin-help.c | ||
| builtin-inject.c | ||
| builtin-kallsyms.c | ||
| builtin-kmem.c | ||
| builtin-kvm.c | ||
| builtin-list.c | ||
| builtin-lock.c | ||
| builtin-mem.c | ||
| builtin-probe.c | ||
| builtin-record.c | ||
| builtin-report.c | ||
| builtin-sched.c | ||
| builtin-script.c | ||
| builtin-stat.c | ||
| builtin-timechart.c | ||
| builtin-top.c | ||
| builtin-trace.c | ||
| builtin-version.c | ||
| builtin.h | ||
| check-headers.sh | ||
| command-list.txt | ||
| CREDITS | ||
| design.txt | ||
| Makefile | ||
| Makefile.config | ||
| Makefile.perf | ||
| MANIFEST | ||
| perf-archive.sh | ||
| perf-completion.sh | ||
| perf-read-vdso.c | ||
| perf-sys.h | ||
| perf-with-kcore.sh | ||
| perf.c | ||
| perf.h | ||