panic: runtime: unknown pc

[andrey mirtchovski]

I believe I've never encountered this nor seen anyone mention this
error before. It occurred while fuzzing a C library that we interface
with:

PC=0x7fffbafc847c m=0 sigcode=0

goroutine 0 [idle]:
runtime: unknown pc 0x7fffbafc847c
stack: frame={sp:0x7fff5fbff088, fp:0x0} stack=[0x7fff5fb80888,0x7fff5fbff8f0)

registers:

rax 0x200018d
rbx 0x7fffc3d971a8
rcx 0x7fff5fbff088
rdx 0x4000
rdi 0x1
rsi 0x4801000
rbp 0x7fff5fbff0b0
rsp 0x7fff5fbff088
r8 0x6
r9 0x7fffbaf18a50
r10 0x72
r11 0x246
r12 0x0
r13 0x7
r14 0x4000
r15 0x4801000
rip 0x7fffbafc847c
rflags 0x246
cs 0x7
fs 0x0
gs 0x0

[full stack trace available upon request, it starts/ends with "cgocall"]

i'm not sure even how to approach this. would that be a runtime issue?
if you have any hints i'd be happy to listen :)

[Ian Lance Taylor]

This is a runtime issue. Note that there have been some fixes for
this on tip. If you have reproduction instructions, please open an
issue. Thanks.

Ian

[andrey mirtchovski]

It is unfortunately not reproducible. I got 2 crashes out of 500
million executions. I've updated to tip and have not seen it since.

[Ian Lance Taylor]

On Fri, May 4, 2018 at 12:12 PM, andrey mirtchovski
<mirtc...@gmail.com> wrote:
> It is unfortunately not reproducible. I got 2 crashes out of 500
> million executions. I've updated to tip and have not seen it since.

It is possible that it has been fixed on tip. There have been fixes
in the right areas, such as https://golang.org/cl/107778. With such
rare occurrences I guess it's hard to be sure, though.

Ian