Hello Go Experts,
It is good if someone can help on this?
Best Regards
Mariappan
On Sat, Apr 1, 2023 at 7:45 AM mariappan balraj <mariappan.bal...@gmail.com>
wrote:
> Hello Go experts,
>
> Could someone please help to resolve this issue?
>
> Best Regards
> Mariappan
>
> On Thu, Mar 30, 2023 at 2:52 PM mariappan balraj <
> mariappan.bal...@gmail.com> wrote:
>
>> Hello Go Experts,
>>
>> When panic() is called from Go function, in the below call sequence,
>> runtime.unwindm() [which is defer function of runtime.cgocallbackg1] is
>> called. This function is unwinding the system stack. Later, as part of the
>> function addOneOpenDeferFrame(), systemstack() is called to run a function
>> in the system stack. This will use the stack which is allocated for C
>> function calls. This makes stack unwinding impossible in case of panic() is
>> called. Can someone please help me to fix this issue?
>>
>> (dlv) bt
>> 0 0x00000000004054e6 in runtime.unwindm
>> at /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/cgocall.go:326
>> 1 0x0000000000405446 in runtime.cgocallbackg1.func3
>> at /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/cgocall.go:304
>> 2 0x00000000004340c8 in runtime.deferCallSave
>> at /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/panic.go:796
>> 3 0x0000000000433fa5 in runtime.runOpenDeferFrame
>> at /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/panic.go:769
>> 4 0x0000000000434332 in runtime.gopanic
>> at /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/panic.go:884
>> 5 0x00000000004642a7 in main.Test4
>> at ./export.go:7
>> at ./export.go:7
>> 6 0x000000000046431c in _cgoexp_78b81bbf688e_Test4
>> at _cgo_gotypes.go:61
>> 7 0x000000000040535b in runtime.cgocallbackg1
>> at /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/cgocall.go:315
>> 8 0x0000000000405079 in runtime.cgocallbackg
>> at /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/cgocall.go:234
>> 9 0x0000000000461b0f in runtime.cgocallbackg
>> at <autogenerated>:1
>> 10 0x000000000045f3f4 in runtime.cgocallback
>> at /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/asm_amd64.s:998
>> 11 0x00000000004641bd in crosscall2
>> at
>> /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/cgo/asm_amd64.s:30
>> 12 0x0000000000464386 in C.Test4
>> at /tmp/go-build/_cgo_export.c:33
>> 13 0x0000000000464432 in C.test1
>> at ./hello.go:9
>> 14 0x000000000046444d in C.test2
>> at ./hello.go:14
>> 15 0x0000000000464468 in C.test3
>> 15 0x0000000000464468 in C.test3
>> at ./hello.go:19
>> 16 0x00000000004644a7 in C._cgo_78b81bbf688e_Cfunc_test3
>> at /tmp/go-build/cgo-gcc-prolog:49
>> 17 0x000000000045f2e4 in runtime.asmcgocall
>> at /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/asm_amd64.s:848
>> 18 0x000000000046448a in C._cgo_78b81bbf688e_Cfunc_test3
>> at /tmp/go-build/cgo-gcc-prolog:44
>> 19 0x0000000000404f0a in runtime.cgocall
>> at /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/cgocall.go:167
>> 20 0x0000000000464245 in main._Cfunc_test3
>> at _cgo_gotypes.go:39
>> 21 0x00000000004642d7 in main.main
>> at ./hello.go:33
>> 22 0x0000000000437073 in runtime.main
>> at /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/proc.go:250
>> 23 0x000000000045f5e1 in runtime.goexit
>> at /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/asm_amd64.s:1598
>>
>> 254 func cgocallbackg1(fn, frame unsafe.Pointer, ctxt uintptr) {
>> 304 defer unwindm(&restore)
>>
>> 326 func unwindm(restore *bool) {
>> 327 if *restore {
>> 328 // Restore sp saved by cgocallback during
>> 329 // unwind of g's stack (see comment at top of file).
>> 330 mp := acquirem()
>> 331 sched := &mp.g0.sched
>> 332 sched.sp = *(*uintptr)(unsafe.Pointer(sched.sp +
>> alignUp(sys.MinFrameSize, sys.StackAlign)))
>>
>> (dlv)
>> > runtime.addOneOpenDeferFrame()
>> /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/panic.go:642 (PC:
>> 0x433a45)
>> Warning: debugging optimized function
>> 637: func addOneOpenDeferFrame(gp *g, pc uintptr, sp unsafe.Pointer) {
>> 638: var prevDefer *_defer
>> 639: if sp == nil {
>> 640: prevDefer = gp._defer
>> 641: pc = prevDefer.framepc
>> => 642: sp = unsafe.Pointer(prevDefer.sp)
>> 643: }
>> 644: systemstack(func() {
>> 645: gentraceback(pc, uintptr(sp), 0, gp, 0, nil,
>> 0x7fffffff,
>> 646: func(frame *stkframe, unused
>> unsafe.Pointer) bool {
>> 647: if prevDefer != nil &&
>> prevDefer.sp == frame.sp {
>> (dlv) bt
>> 0 0x0000000000433a45 in runtime.addOneOpenDeferFrame
>> at /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/panic.go:642
>> 1 0x0000000000434357 in runtime.gopanic
>> at /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/panic.go:886
>> 2 0x00000000004642a7 in main.Test4
>> at ./export.go:7
>>
>> On Tue, Mar 28, 2023 at 4:14 PM mariappan balraj <
>> mariappan.bal...@gmail.com> wrote:
>>
>>> Hello Go Experts,
>>>
>>> I am observing system stack corruption when panic() is called from go
>>> function. When panic is called from Test4(), as part of
>>> runtime.systemstack_switch(), the RSP and RBP is set in such a way that it
>>> will corrupt the stack.
>>>
>>> Rbp = 0x00007ffdb188bd20===> This should be less than 0x7ffdb188bc50.
>>> But it is set to the value which is already used for CGO calls. So it is
>>> making the system stack to corrupt. When the core file is generated, it
>>> makes it unable to debug from the core file using dlv. Can someone please
>>> help on this issue?
>>>
>>> RBP 0x7ffdb188bc50 RA 0x45f3f4 runtime.cgocallback
>>> /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/asm_amd64.s 1003
>>> RBP 0x7ffdb188bca0 RA 0x4641bd crosscall2
>>> /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/cgo/asm_amd64.s 32
>>> RBP 0x7ffdb188bcd0 RA 0x464386 C.Test4 /tmp/go-build/_cgo_export.c 35
>>> RBP 0x7ffdb188bce0 RA 0x464432 C.test1
>>> /home/soomohan/mbalraj/test/hello.go 10
>>> RBP 0x7ffdb188bd00 RA 0x46444d C.test2
>>> /home/soomohan/mbalraj/test/hello.go 15
>>> RBP 0x7ffdb188bd20 RA 0x464468 C.test3
>>> /home/soomohan/mbalraj/test/hello.go 20
>>> RBP 0x7ffdb188bd50 RA 0x4644a7 C._cgo_78b81bbf688e_Cfunc_test3
>>> /tmp/go-build/cgo-gcc-prolog 51
>>>
>>> go version
>>> go version go1.20.2 linux/amd64
>>>
>>> //hello.go
>>> package main
>>>
>>> /*
>>> #include <stdio.h>
>>>
>>> extern void Test4(void);
>>>
>>> void test1(void) {
>>> Test4();
>>> }
>>>
>>> void test2(void) {
>>> int val = 2;
>>> test1();
>>> }
>>>
>>> void test3(void) {
>>> int val = 3;
>>> test2();
>>> }
>>>
>>> void test4(void) {
>>> printf("Test4()");
>>> }
>>> */
>>> import "C"
>>>
>>> func Test5() {
>>> C.test4()
>>> }
>>>
>>> func main() {
>>> C.test3()
>>> }
>>>
>>> //export.go
>>> package main
>>>
>>> import "C"
>>>
>>> //export Test4
>>> func Test4() {
>>> panic("Panic inside Test4")
>>> //Test5()
>>> }
>>>
>>> I have written the following script test.start to debug this issue
>>> further in DLV.
>>> def command_goroutine_start_line(args):
>>> regs = registers().Regs
>>> rip = 0
>>> for reg in regs:
>>> if reg.Name == "Rbp":
>>> rbp = int(reg.Value, 16)
>>> elif reg.Name == "Rip":
>>> rip = int(reg.Value, 16)
>>>
>>> da = disassemble(StartPC=rip, EndPC=rip+1).Disassemble
>>> print("RBP 0x%x RIP 0x%x %s %s %s" % (rbp, rip,
>>> da[0].Loc.Function.Name_, da[0].Loc.File, da[0].Loc.Line))
>>>
>>> while True:
>>> mem = examine_memory(rbp, 8).Mem
>>> val = 0
>>> for i in range(len(mem)):
>>> val <<= 8
>>> val += mem[len(mem) - i - 1]
>>> prbp = val
>>>
>>> mem = examine_memory(rbp + 8, 8).Mem
>>> val = 0
>>> for i in range(len(mem)):
>>> val <<= 8
>>> val += mem[len(mem) - i - 1]
>>> ra = val
>>>
>>> da = disassemble(StartPC=ra, EndPC=ra+1).Disassemble
>>> print("RBP 0x%x RA 0x%x %s %s %s" % (prbp, ra,
>>> da[0].Loc.Function.Name_, da[0].Loc.File, da[0].Loc.Line))
>>> if prbp == 0:
>>> break
>>> rbp = prbp
>>>
>>> def main():
>>> dlv_command("config alias goroutine_start_line gsl")
>>>
>>> (dlv)bt
>>> RBP 0x0 RA 0x45f5e1 runtime.goexit
>>> /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/asm_amd64.s 1599
>>>
>>> 0 0x0000000000433b04 in runtime.addOneOpenDeferFrame.func1
>>> at /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/panic.go:646
>>> 1 0x000000000045f0c0 in runtime.systemstack_switch
>>> at /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/asm_amd64.s:463
>>> 2 0x0000000000433a89 in runtime.addOneOpenDeferFrame
>>> at /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/panic.go:644
>>> 3 0x0000000000434357 in runtime.gopanic
>>> at /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/panic.go:886
>>> 4 0x00000000004642a7 in main.Test4
>>> at ./export.go:7
>>> 5 0x000000000046431c in _cgoexp_78b81bbf688e_Test4
>>> at _cgo_gotypes.go:61
>>> 6 0x000000000040535b in runtime.cgocallbackg1
>>> at /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/cgocall.go:315
>>> 7 0x0000000000405079 in runtime.cgocallbackg
>>> at /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/cgocall.go:234
>>> 8 0x0000000000461b0f in runtime.cgocallbackg
>>> at <autogenerated>:1
>>> 9 0x000000000045f3f4 in runtime.cgocallback
>>> at /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/asm_amd64.s:998
>>> 10 0x0000000000000001 in ???
>>> at ?:-1
>>> 11 0x0000000000464386 in C.Test4
>>> at /tmp/go-build/_cgo_export.c:33
>>> 12 0x0000000000464432 in C.test1
>>> at ./hello.go:9
>>> 13 0x000000000046444d in C.test2
>>> at ./hello.go:14
>>> 14 0x0000000000464468 in C.test3
>>> at ./hello.go:19
>>> 15 0x00000000004644a7 in C._cgo_78b81bbf688e_Cfunc_test3
>>> 15 0x00000000004644a7 in C._cgo_78b81bbf688e_Cfunc_test3
>>> at /tmp/go-build/cgo-gcc-prolog:49
>>> 16 0x000000000045f2e4 in runtime.asmcgocall
>>> at /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/asm_amd64.s:848
>>> 17 0x000000000046448a in C._cgo_78b81bbf688e_Cfunc_test3
>>> at /tmp/go-build/cgo-gcc-prolog:44
>>> 18 0x0000000000404f0a in runtime.cgocall
>>> at /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/cgocall.go:167
>>> 19 0x0000000000464245 in main._Cfunc_test3
>>> at _cgo_gotypes.go:39
>>> 20 0x00000000004642d7 in main.main
>>> at ./hello.go:33
>>> 21 0x0000000000437073 in runtime.main
>>> at /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/proc.go:250
>>> 22 0x000000000045f5e1 in runtime.goexit
>>> at /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/asm_amd64.s:1598
>>>
>>> (dlv)source test.star
>>> (dlv)gsl
>>> (dlv) gsl
>>> RBP 0xc000048c68 RIP 0x433b04 runtime.addOneOpenDeferFrame.func1
>>> /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/panic.go 646
>>> RBP 0xc000048d28 RA 0x434357 runtime.gopanic
>>> /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/panic.go 905
>>> RBP 0xc000048d48 RA 0x4642a7 main.Test4
>>> /home/soomohan/mbalraj/test/export.go 7
>>> RBP 0xc000048d58 RA 0x46431c _cgoexp_78b81bbf688e_Test4 _cgo_gotypes.go
>>> 62
>>> RBP 0xc000048e18 RA 0x40535b runtime.cgocallbackg1
>>> /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/cgocall.go 323
>>> RBP 0xc000048ea8 RA 0x405079 runtime.cgocallbackg
>>> /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/cgocall.go 240
>>> RBP 0xc000048ed0 RA 0x461b0f runtime.cgocallbackg <autogenerated> 1
>>> RBP 0x7ffdb188bc50 RA 0x45f3f4 runtime.cgocallback
>>> /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/asm_amd64.s 1003
>>> RBP 0x7ffdb188bca0 RA 0x4641bd crosscall2
>>> /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/cgo/asm_amd64.s 32
>>> RBP 0x7ffdb188bcd0 RA 0x464386 C.Test4 /tmp/go-build/_cgo_export.c 35
>>> RBP 0x7ffdb188bce0 RA 0x464432 C.test1
>>> /home/soomohan/mbalraj/test/hello.go 10
>>> RBP 0x7ffdb188bd00 RA 0x46444d C.test2
>>> /home/soomohan/mbalraj/test/hello.go 15
>>> RBP 0x7ffdb188bd20 RA 0x464468 C.test3
>>> /home/soomohan/mbalraj/test/hello.go 20
>>> RBP 0x7ffdb188bd50 RA 0x4644a7 C._cgo_78b81bbf688e_Cfunc_test3
>>> /tmp/go-build/cgo-gcc-prolog 51
>>> RBP 0xc000048f38 RA 0x45f2e4 runtime.asmcgocall
>>> /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/asm_amd64.s 852
>>> RBP 0xc000048f60 RA 0x464245 main._Cfunc_test3 _cgo_gotypes.go 40
>>> RBP 0xc000048f70 RA 0x4642d7 main.main
>>> /home/soomohan/mbalraj/test/hello.go 33
>>> RBP 0xc000048fd0 RA 0x437073 runtime.main
>>> /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/proc.go 260
>>> RBP 0x0 RA 0x45f5e1 runtime.goexit
>>> /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/asm_amd64.s 1599
>>>
>>> (dlv)si
>>>
>>> (dlv)bt
>>> 0 0x000000000045587f in runtime.gentraceback
>>> at /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/traceback.go:32
>>> 1 0x000000000045f0c0 in runtime.systemstack_switch
>>> at /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/asm_amd64.s:463
>>> 2 0x0000000000433a89 in runtime.addOneOpenDeferFrame
>>> at /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/panic.go:644
>>> 3 0x0000000000434357 in runtime.gopanic
>>> at /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/panic.go:886
>>> 4 0x00000000004642a7 in main.Test4
>>> at ./export.go:7
>>> 5 0x000000000046431c in _cgoexp_78b81bbf688e_Test4
>>> at _cgo_gotypes.go:61
>>> 6 0x000000000040535b in runtime.cgocallbackg1
>>> at /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/cgocall.go:315
>>> 7 0x0000000000405079 in runtime.cgocallbackg
>>> at /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/cgocall.go:234
>>> 8 0x0000000000461b0f in runtime.cgocallbackg
>>> at <autogenerated>:1
>>> 9 0x000000000045f3f4 in runtime.cgocallback
>>> at /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/asm_amd64.s:998
>>> 10 0x0000000000000001 in ???
>>> at ?:-1
>>> 11 0x0000000000464386 in C.Test4
>>> at /tmp/go-build/_cgo_export.c:33
>>> 12 0x0000000000464432 in C.test1
>>> at ./hello.go:9
>>> 13 0x000000000046444d in C.test2
>>> at ./hello.go:14
>>> 14 0x0000000000464468 in C.test3
>>> at ./hello.go:19
>>> 15 0x0000000000433b4b in runtime.addOneOpenDeferFrame.func1
>>> 15 0x0000000000433b4b in runtime.addOneOpenDeferFrame.func1
>>> at /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/panic.go:645
>>> 16 0x000000000045f129 in runtime.systemstack
>>> at /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/asm_amd64.s:496
>>> 17 0x0000000000461da5 in runtime.newproc
>>> at <autogenerated>:1
>>> 18 0x00000000004cc720 in ???
>>> at ?:-1
>>> 19 0x000000000046431c in _cgoexp_78b81bbf688e_Test4
>>> at _cgo_gotypes.go:61
>>> 20 0x000000000040535b in runtime.cgocallbackg1
>>> at /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/cgocall.go:315
>>> 21 0x0000000000405079 in runtime.cgocallbackg
>>> at /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/cgocall.go:234
>>> 22 0x0000000000461b0f in runtime.cgocallbackg
>>> at <autogenerated>:1
>>> 23 0x000000000045f3f4 in runtime.cgocallback
>>> at /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/asm_amd64.s:998
>>> 24 0x000000000045f0c0 in runtime.systemstack_switch
>>> at /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/asm_amd64.s:463
>>> 25 0x0000000000404f0a in runtime.cgocall
>>> at /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/cgocall.go:167
>>> 26 0x0000000000464245 in main._Cfunc_test3
>>> at _cgo_gotypes.go:39
>>> 27 0x00000000004642d7 in main.main
>>> at ./hello.go:33
>>> 28 0x0000000000437073 in runtime.main
>>> at /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/proc.go:250
>>> 29 0x000000000045f5e1 in runtime.goexit
>>> at /home/soomohan/mbalraj/GO/go1.20.2/go/src/runtime/asm_amd64.s:1598
>>>
>>> (dlv) regs
>>> (dlv) regs
>>> Rip = 0x000000000045587f
>>> Rsp = 0x00007ffdb188ba08
>>> Rax = 0x000000000040535b
>>> Rbx = 0x000000c000048d68
>>> Rcx = 0x0000000000000000
>>> Rdx = 0x0000000000433b60
>>> Rsi = 0x0000000000000000
>>> Rdi = 0x000000c0000061a0
>>> Rbp = 0x00007ffdb188bd20
>>> R8 = 0x0000000000000000
>>> R9 = 0x000000007fffffff
>>> R10 = 0x00007ffdb188bd80
>>> R11 = 0x0000000000000000
>>> R12 = 0x00007ffdb188ba88
>>> R13 = 0x000000c000048c18
>>> R14 = 0x00000000004cc720
>>> R15 = 0x0000000000000000
>>> Rflags = 0x0000000000000246 [PF ZF IF IOPL=0]
>>> Es = 0x0000000000000000
>>> Cs = 0x0000000000000033
>>> Ss = 0x000000000000002b
>>> Ds = 0x0000000000000000
>>> Fs = 0x0000000000000000
>>> Gs = 0x0000000000000000
>>> Fs_base = 0x000015128ba66740
>>> Gs_base = 0x0000000000000000
>>>
>>> Best Regards
>>> Mariappan
>>>
>>
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