bpftrace 段错误 bpf_prog_load_deprecated

Posted 2022-08-27 rtoax

调试

(gdb)
672       return bpf_prog_load(load_attr->prog_type, load_attr->name, load_attr->license,
(gdb) p load_attr->prog_type
$5 = BPF_PROG_TYPE_TRACING
(gdb) s
bpf_prog_load_deprecated (file=0x1a <error: Cannot access memory at address 0x1a>, type=4294942496, pobj=0x75e898, prog_fd=0x7fffffffb340) at libbpf.c:10153
10153           memset(&attr, 0, sizeof(struct bpf_prog_load_attr));

如何解决

方法1：Fix bpf_prog_load() pointing error causing libbcc segfault by Rtoax · Pull Request #503 · libbpf/libbpf · GitHubbpftrace SEGV fault:(gdb) bt#0 0x00007ffff00eee7d in __strlen_avx2 () from /lib64/libc.so.6#1 0x00007ffff0095278 in __vfprintf_internal () from /lib64/libc.so.6#2 0x00007ffff0095a3f in buffered_vfprintf () from /lib64/libc.so.6#3 0x00007ffff7f68c10 in libbpf_print (level=level@entry=LIBBPF_DEBUG, format=format@entry=0x7ffff7f9452e "libbpf: loading %s\\n") at libbpf.c:103#4 0x00007ffff7f75e82 in __bpf_object__open_xattr (attr=attr@entry=0x7fffffffaf40, flags=0) at libbpf.c:7435#5 0x00007ffff7f7d917 in bpf_prog_load_xattr2 (attr=attr@entry=0x7fffffffaf90, pobj=0x5555557a310b, prog_fd=0x7fffffffc590) at libbpf.c:10093#6 0x00007ffff7f7dad3 in bpf_prog_load_deprecated (file=, type=, pobj=, prog_fd=) at libbpf.c:10158#7 0x00007ffff1025c78 in libbpf_bpf_prog_load (load_attr=0x7fffffffb210, log_buf=0x0, log_buf_sz=0) at /home/rongtao/Git/bcc/src/cc/libbpf.c:672#8 0x00007ffff10260af in bcc_prog_load_xattr (attr=0x7fffffffb210, prog_len=16, log_buf=0x7fffffffb540 "", log_buf_size=4096, allow_rlimit=true) at /home/rongtao/Git/bcc/src/cc/libbpf.c:758#9 0x00007ffff10264c7 in bcc_prog_load (prog_type=BPF_PROG_TYPE_TRACING, name=0x5555557a30a9 "kfunc__sched_fork", insns=0x7fffffffc590, prog_len=16, license=0x5555557a310b "GPL", kern_version=331533, log_level=0, log_buf=0x7fffffffb540 "", log_buf_size=4096) at /home/rongtao/Git/bcc/src/cc/libbpf.c:880#10 0x00005555556cd65c in bpftrace::try_load(char const*, libbpf::bpf_prog_type, bpf_insn*, unsigned long, int, char*, unsigned long) [clone .constprop.0] ( name=name@entry=0x5555557a30a9 "kfunc__sched_fork", prog_type=prog_type@entry=libbpf::BPF_PROG_TYPE_TRACING, insns=insns@entry=0x7fffffffc590, insns_cnt=insns_cnt@entry=2, loglevel=loglevel@entry=0, logbuf=logbuf@entry=0x7fffffffb540 "", logbuf_size=4096) at /usr/src/debug/bpftrace-0.12.1-8.el9.x86_64/src/bpffeature.cpp:45#11 0x0000555555621341 in bpftrace::try_load (prog_type=, insns=0x7fffffffc590, len=2, name=) at /usr/src/debug/bpftrace-0.12.1-8.el9.x86_64/src/bpffeature.cpp:87#12 0x0000555555621505 in bpftrace::BPFfeature::detect_prog_type (this=0x555555a17a10, name=0x0, prog_type=libbpf::BPF_PROG_TYPE_TRACING) at /usr/src/debug/bpftrace-0.12.1-8.el9.x86_64/src/bpffeature.cpp:141#13 bpftrace::BPFfeature::has_prog_kfunc (this=0x555555a17a10) at /usr/src/debug/bpftrace-0.12.1-8.el9.x86_64/src/bpffeature.h:102#14 0x00005555556ad121 in bpftrace::ast::SemanticAnalyser::visit (this=0x7fffffffdd50, ap=...) at /usr/src/debug/bpftrace-0.12.1-8.el9.x86_64/src/ast/semantic_analyser.cpp:2552#15 0x00005555556a8ee3 in bpftrace::ast::AttachPoint::accept (v=..., this=0x555555a20f90) at /usr/src/debug/bpftrace-0.12.1-8.el9.x86_64/src/ast/ast.cpp:36#16 bpftrace::ast::SemanticAnalyser::visit (this=0x7fffffffdd50, probe=...) at /usr/src/debug/bpftrace-0.12.1-8.el9.x86_64/src/ast/semantic_analyser.cpp:2625#17 0x00005555556a4144 in bpftrace::ast::Probe::accept (v=..., this=) at /usr/src/debug/bpftrace-0.12.1-8.el9.x86_64/src/ast/ast.cpp:41#18 bpftrace::ast::SemanticAnalyser::visit (this=0x7fffffffdd50, program=...) at /usr/src/debug/bpftrace-0.12.1-8.el9.x86_64/src/ast/semantic_analyser.cpp:2642#19 0x00005555556a427b in bpftrace::ast::SemanticAnalyser::analyse (this=0x7fffffffdd50) at /usr/src/debug/bpftrace-0.12.1-8.el9.x86_64/src/ast/semantic_analyser.cpp:2653#20 0x00005555555e40d6 in main (argc=2, argv=0x7fffffffe678) at /usr/src/debug/bpftrace-0.12.1-8.el9.x86_64/src/main.cpp:532In 'libbpf_bpf_prog_load()' call 'bpf_prog_load()' with 6 args, shouldn't call 'bpf_prog_load_deprecated()' with 4 args. but was called.See also iovisor/bcc#4021https://github.com/libbpf/libbpf/pull/503

方法2：

Fix bpftrace segfault caused by libbcc bug. by Rtoax · Pull Request #4021 · iovisor/bcc · GitHubbpftrace libbcc SEGV fault:$ sudo gdb bpftrace[...](gdb) set args -l(gdb) rProgram received signal SIGSEGV, Segmentation fault.0x00007ffff00eee7d in __strlen_avx2 () from /lib64/libc.so.6(gdb) bt#0 0x00007ffff00eee7d in __strlen_avx2 () from /lib64/libc.so.6#1 0x00007ffff0095278 in __vfprintf_internal () from /lib64/libc.so.6#2 0x00007ffff0095a3f in buffered_vfprintf () from /lib64/libc.so.6#3 0x00007ffff7f68c10 in libbpf_print (level=level@entry=LIBBPF_DEBUG, format=format@entry=0x7ffff7f9452e "libbpf: loading %s\\n") at libbpf.c:103#4 0x00007ffff7f75e82 in __bpf_object__open_xattr (attr=attr@entry=0x7fffffffaf40, flags=0) at libbpf.c:7435#5 0x00007ffff7f7d917 in bpf_prog_load_xattr2 (attr=attr@entry=0x7fffffffaf90, pobj=0x5555557a310b, prog_fd=0x7fffffffc590) at libbpf.c:10093#6 0x00007ffff7f7dad3 in bpf_prog_load_deprecated (file=, type=, pobj=, prog_fd=) at libbpf.c:10158#7 0x00007ffff1025c78 in libbpf_bpf_prog_load (load_attr=0x7fffffffb210, log_buf=0x0, log_buf_sz=0) at /home/rongtao/Git/bcc/src/cc/libbpf.c:672#8 0x00007ffff10260af in bcc_prog_load_xattr (attr=0x7fffffffb210, prog_len=16, log_buf=0x7fffffffb540 "", log_buf_size=4096, allow_rlimit=true) at /home/rongtao/Git/bcc/src/cc/libbpf.c:758#9 0x00007ffff10264c7 in bcc_prog_load (prog_type=BPF_PROG_TYPE_TRACING, name=0x5555557a30a9 "kfunc__sched_fork", insns=0x7fffffffc590, prog_len=16, license=0x5555557a310b "GPL", kern_version=331533, log_level=0, log_buf=0x7fffffffb540 "", log_buf_size=4096) at /home/rongtao/Git/bcc/src/cc/libbpf.c:880#10 0x00005555556cd65c in bpftrace::try_load(char const*, libbpf::bpf_prog_type, bpf_insn*, unsigned long, int, char*, unsigned long) [clone .constprop.0] ( name=name@entry=0x5555557a30a9 "kfunc__sched_fork", prog_type=prog_type@entry=libbpf::BPF_PROG_TYPE_TRACING, insns=insns@entry=0x7fffffffc590, insns_cnt=insns_cnt@entry=2, loglevel=loglevel@entry=0, logbuf=logbuf@entry=0x7fffffffb540 "", logbuf_size=4096) at /usr/src/debug/bpftrace-0.12.1-8.el9.x86_64/src/bpffeature.cpp:45#11 0x0000555555621341 in bpftrace::try_load (prog_type=, insns=0x7fffffffc590, len=2, name=) at /usr/src/debug/bpftrace-0.12.1-8.el9.x86_64/src/bpffeature.cpp:87#12 0x0000555555621505 in bpftrace::BPFfeature::detect_prog_type (this=0x555555a17a10, name=0x0, prog_type=libbpf::BPF_PROG_TYPE_TRACING) at /usr/src/debug/bpftrace-0.12.1-8.el9.x86_64/src/bpffeature.cpp:141#13 bpftrace::BPFfeature::has_prog_kfunc (this=0x555555a17a10) at /usr/src/debug/bpftrace-0.12.1-8.el9.x86_64/src/bpffeature.h:102#14 0x00005555556ad121 in bpftrace::ast::SemanticAnalyser::visit (this=0x7fffffffdd50, ap=...) at /usr/src/debug/bpftrace-0.12.1-8.el9.x86_64/src/ast/semantic_analyser.cpp:2552#15 0x00005555556a8ee3 in bpftrace::ast::AttachPoint::accept (v=..., this=0x555555a20f90) at /usr/src/debug/bpftrace-0.12.1-8.el9.x86_64/src/ast/ast.cpp:36#16 bpftrace::ast::SemanticAnalyser::visit (this=0x7fffffffdd50, probe=...) at /usr/src/debug/bpftrace-0.12.1-8.el9.x86_64/src/ast/semantic_analyser.cpp:2625#17 0x00005555556a4144 in bpftrace::ast::Probe::accept (v=..., this=) at /usr/src/debug/bpftrace-0.12.1-8.el9.x86_64/src/ast/ast.cpp:41#18 bpftrace::ast::SemanticAnalyser::visit (this=0x7fffffffdd50, program=...) at /usr/src/debug/bpftrace-0.12.1-8.el9.x86_64/src/ast/semantic_analyser.cpp:2642#19 0x00005555556a427b in bpftrace::ast::SemanticAnalyser::analyse (this=0x7fffffffdd50) at /usr/src/debug/bpftrace-0.12.1-8.el9.x86_64/src/ast/semantic_analyser.cpp:2653#20 0x00005555555e40d6 in main (argc=2, argv=0x7fffffffe678) at /usr/src/debug/bpftrace-0.12.1-8.el9.x86_64/src/main.cpp:532In 'libbpf_bpf_prog_load()' call 'bpf_prog_load()' with 6 args, shouldn't call 'bpf_prog_load_deprecated()' with 4 args. but was called, It may be caused by a libbpf bug, which can be circumvented in this way.Fix it in libbpf/libbpf#503https://github.com/iovisor/bcc/pull/4021