Hi there,
I want to practice *bpftrace* tracing go program exit point, such as,
*runtime.gopanic* and *os.Exit*, but I'm confused with the result (there's
different stack information between* runtime.panic* and
*syscall.Exit/os.Exit*):
[root@localhost trace-go-func]# bpftrace -c "./binary -mode exit -code 2"
trace.bt Attaching 2 probes...
mode=exit, ecode=2
syscall.Exit(2) called with stack:
458080 0x458080 ([unknown])
487f9e 0x487f9e ([unknown])
487ee6 0x487ee6 ([unknown])
433192 0x433192 ([unknown])
45ba81 0x45ba81 ([unknown])
[root@localhost trace-go-func]# bpftrace -c "./binary -mode panic"
trace.bt
Attaching 2 probes...
mode=panic, ecode=0
panic called with stack
430280 runtime.gopanic+0 (/root/projects/trace-go-func/binary)
487f05 main.main+293 (/root/projects/trace-go-func/binary)
433192 runtime.main+530 (/root/projects/trace-go-func/binary)
45ba81 runtime.goexit.abi0+1 (/root/projects/trace-go-func/binary)
panic: doPanic
goroutine 1 [running]:
main.doPanic() /root/projects/trace-go-func/main.go:31 +0x27
main.main() /root/projects/trace-go-func/main.go:22 +0x125
as you see, panic works well, but os.Exit could not get stack correctly. I
have found symbols with addresses in nm like this, for x in 458080 487f9e
487ee6; do nm ./binary | grep $x; done, but only 458080 syscall.Exit was
got.
I'm confused now, why *bpftrace* could get the address and symbols while
*runtime.gopanic* but *os.Exit*, and even could not be matched in nm?
*main.go looks like:*
*package main *
*import ( "flag" "fmt" "os" ) *
*var ( *
* mode = flag.String("mode", "exit", "choose mode to run and test") *
* code = flag.Int("code", 0, "os.Exit code") *
*) *
*func main() { *
* flag.Parse() *
* fmt.Printf("mode=%s, ecode=%d\n", *mode, *code) *
*// defer fmt.Println("main quit") *
*switch *mode { *
*case "panic": doPanic() *
*case "exit": doOSExit(*code) *
* } *
*} *
*//go:noinline *
*func doPanic() { *
*// fmt.Println("panic calling") *
*panic("doPanic") *
*} *
*//go:noinline func doOSExit(code int) { *
*// fmt.Println("os.Exit calling") *
* os.Exit(code) *
*}*
*trace.bt looks like:*
*uprobe:./binary:runtime.gopanic *
*{ *
* printf("panic called with stack %s", ustack(perf)); *
*} *
*uprobe:./binary:syscall.Exit { *
* printf("syscall.Exit(%d) called with stack: %s", sarg0, ustack(perf)); *
*}*
*Enviroments:*
OS: centos7
Kernel: 5.4.188-1.el7.elrepo.x86_64
bpftrace: v0.13.0
go: 1.18
the following link maybe look better
1. linux - got unknown stack while capturing go binary exit point with
bpftrace - Stack Overflow
<https://stackoverflow.com/questions/71868301/got-unknown-stack-while-capturing-go-binary-exit-point-with-bpftrace>
--
You received this message because you are subscribed to the Google Groups
"golang-nuts" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to golang-nuts+unsubscr...@googlegroups.com.
To view this discussion on the web visit
https://groups.google.com/d/msgid/golang-nuts/4acd1e09-d8a1-461d-a6f4-9956913c1c03n%40googlegroups.com.
