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ab8bf5f2e0
The addr in PERF_RECORD_KSYMBOL events for non-jited bpf progs points to the bpf interpreter, ie. within kernel text section. When processing the unregister event, this causes unexpected removal of vmlinux_map, crashing perf later in cleanup: # perf record -- timeout --signal=INT 2s /usr/share/bcc/tools/execsnoop PCOMM PID PPID RET ARGS [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.208 MB perf.data (5155 samples) ] perf: tools/include/linux/refcount.h:131: refcount_sub_and_test: Assertion `!(new > val)' failed. Aborted (core dumped) # perf script -D|grep KSYM 0 0xa40 [0x48]: PERF_RECORD_KSYMBOL addr ffffffffa9b6b530 len 0 type 1 flags 0x0 name bpf_prog_f958f6eb72ef5af6 0 0xab0 [0x48]: PERF_RECORD_KSYMBOL addr ffffffffa9b6b530 len 0 type 1 flags 0x0 name bpf_prog_8c42dee26e8cd4c2 0 0xb20 [0x48]: PERF_RECORD_KSYMBOL addr ffffffffa9b6b530 len 0 type 1 flags 0x0 name bpf_prog_f958f6eb72ef5af6 108563691893 0x33d98 [0x58]: PERF_RECORD_KSYMBOL addr ffffffffa9b6b3b0 len 0 type 1 flags 0x0 name bpf_prog_bc5697a410556fc2_syscall__execve 108568518458 0x34098 [0x58]: PERF_RECORD_KSYMBOL addr ffffffffa9b6b3f0 len 0 type 1 flags 0x0 name bpf_prog_45e2203c2928704d_do_ret_sys_execve 109301967895 0x34830 [0x58]: PERF_RECORD_KSYMBOL addr ffffffffa9b6b3b0 len 0 type 1 flags 0x1 name bpf_prog_bc5697a410556fc2_syscall__execve 109302007356 0x348b0 [0x58]: PERF_RECORD_KSYMBOL addr ffffffffa9b6b3f0 len 0 type 1 flags 0x1 name bpf_prog_45e2203c2928704d_do_ret_sys_execve perf: tools/include/linux/refcount.h:131: refcount_sub_and_test: Assertion `!(new > val)' failed. Here the addresses match the bpf interpreter: # grep -e ffffffffa9b6b530 -e ffffffffa9b6b3b0 -e ffffffffa9b6b3f0 /proc/kallsyms ffffffffa9b6b3b0 t __bpf_prog_run224 ffffffffa9b6b3f0 t __bpf_prog_run192 ffffffffa9b6b530 t __bpf_prog_run32 Fix by not allowing vmlinux_map to be removed by PERF_RECORD_KSYMBOL unregister event. Signed-off-by: Tommi Rantala <tommi.t.rantala@nokia.com> Acked-by: Jiri Olsa <jolsa@redhat.com> Tested-by: Jiri Olsa <jolsa@redhat.com> Link: https://lore.kernel.org/r/20201016114718.54332-1-tommi.t.rantala@nokia.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 | ||