Repository: go
Issue: runtime: SIGSEGV crash on Linux in docker container, possible net/http crash
Labels: NeedsInvestigation,compiler/runtime

Context I run 2 binaries inside a docker container, one open source project (first crash) and another closed source (second crash). 
Both of them crashed with `signal SIGSEGV: segmentation violation`

The first crash started with these lines:
```
0x2000: fatal error: unexpected signal during runtime execution
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x0]
goroutine 301131 [running]:
runtime.throw({0xff4e03, 0x2})
/usr/local/go/src/runtime/panic.go:1198 +0x71 fp=0xc010903260 sp=0xc010903230 pc=0x4355b1
runtime.sigpanic()
/usr/local/go/src/runtime/signal_unix.go:719 +0x396 fp=0xc0109032b0 sp=0xc010903260 pc=0x44ba36
runtime: unexpected return pc for runtime.hexdumpWords called from 0x40
stack: frame={sp:0xc0109032b0, fp:0xc010903310} stack=[0xc010902000,0xc010904000)
```

The second crash started with these lines:
```
fatal error: unexpected signal during runtime execution
[signal SIGSEGV: segmentation violation code=0x1 addr=0x194b8 pc=0x436da4]
runtime stack:
runtime: unexpected return pc for runtime.acquireSudog called from 0xc00004be30
stack: frame={sp:0xc0003adf28, fp:0xc0003adf98} stack=[0xc0003ac000,0xc0003ae000)
```

### What version of Go are you using (`go version`)?

The open source project runs with Go `1.17.6`.
The closed source project with Go `1.14.4`.
Both `linux/amd64`.

### Does this issue reproduce with the latest release?

I can't reproduce it, it's an event that I never observed before and we run about 400 instances across 95 clusters with more than 1M RPS.

### What operating system and processor architecture are you using (`go env`)?

<details><summary><code>go env</code> Output</summary><br><pre>
$ go env

GO111MODULE=""

GOARCH="amd64"
GOBIN="/usr/local/bin"
GOCACHE="/root/.cache/go-build"
GOENV="/root/.config/go/env"
GOEXE=""
GOEXPERIMENT=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOINSECURE=""
GOMODCACHE="/go/pkg/mod"
GONOPROXY="github.example.org"
GONOSUMDB="github.example.org"
GOOS="linux"
GOPATH="/go"
GOPRIVATE="github.example.org"
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/local/go"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/local/go/pkg/tool/linux_amd64"
GOVCS=""
GOVERSION="go1.17.6"
GCCGO="gccgo"
AR="ar"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD="/workspace/go.mod"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build3473157175=/tmp/go-build -gno-record-gcc-switches"
</pre></details>

### What did you do?

We run 2 processes in one docker container. One process is the open source project, which is a http reverse proxy with some more features like authnz calls to another http endpoint. The second process is the close source project which is a http server handler that does JWT validation, which is called by the first process to validate the token.
At runtime both processes crashed. 
It's a single occurrence and I found https://github.com/golang/go/wiki/LinuxKernelSignalVectorBug  which is mentioned in the second crash logs. However I could not reproduce the Bug test https://github.com/golang/go/wiki/LinuxKernelSignalVectorBug#bug-test. I tested with the same gcc version as the kernel.

Gcc version:
```
gcc (Ubuntu 9.3.0-17ubuntu1~20.04) 9.3.0
```

Kernel version:
```
% uname -a
Linux ip-172-31-22-74 5.4.0-1063-aws #66-Ubuntu SMP Wed Jan 12 17:49:45 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux
%  cat /proc/version_signature 
Ubuntu 5.4.0-1063.66-aws 5.4.157
```

We run all nodes without swap, for example:
```
% free
              total        used        free      shared  buff/cache   available
Mem:       15803320     1581248    12482748        3600     1739324    13949664
Swap:             0           0           0
```

The first crash logs
[go_1st_crash.log](https://github.com/golang/go/files/8035924/go_1st_crash.log)

The second crash logs
[go_2nd_crash.log](https://github.com/golang/go/files/8035928/go_2nd_crash.log)


### What did you expect to see?

no crash

### What did you see instead?

a crash