code review 63520043: net/http: increase panic stack trace buffer size from 4...

net/http: increase panic stack trace buffer size from 4 KB to 64 KB.

4 KB is a bit too small in some situations (e.g. panic during a
template execution), and ends up with an unhelpfully-truncated trace.
64 KB should be much more likely to capture the useful information.
There's not a garbage generation issue, since this code should only
be triggered when there's something seriously wrong with the program.

[dsymonds, 2014-02-13 23:08:01]

Hello bradfitz (cc: golang-codereviews@googlegroups.com),

I'd like you to review this change to
https://go.googlecode.com/hg/

[bradfitz, 2014-02-13 23:12:30]

LGTM



On Thu, Feb 13, 2014 at 3:08 PM, <dsymonds@golang.org> wrote:

> Reviewers: bradfitz,
>
> Message:
> Hello bradfitz (cc: golang-codereviews@googlegroups.com),
>
> I'd like you to review this change to
> https://go.googlecode.com/hg/
>
>
> Description:
> net/http: increase panic stack trace buffer size from 4 KB to 64 KB.
>
> 4 KB is a bit too small in some situations (e.g. panic during a
> template execution), and ends up with an unhelpfully-truncated trace.
> 64 KB should be much more likely to capture the useful information.
> There's not a garbage generation issue, since this code should only
> be triggered when there's something seriously wrong with the program.
>
> Please review this at https://codereview.appspot.com/63520043/
>
> Affected files (+1, -1 lines):
>   M src/pkg/net/http/server.go
>
>
> Index: src/pkg/net/http/server.go
> ===================================================================
> --- a/src/pkg/net/http/server.go
> +++ b/src/pkg/net/http/server.go
> @@ -1083,7 +1083,7 @@
>  func (c *conn) serve() {
>         defer func() {
>                 if err := recover(); err != nil {
> -                       const size = 4096
> +                       const size = 64 << 10
>                         buf := make([]byte, size)
>                         buf = buf[:runtime.Stack(buf, false)]
>                         log.Printf("http: panic serving %v: %v\n%s",
> c.remoteAddr, err, buf)
>
>
>

[dsymonds, 2014-02-13 23:15:44]

*** Submitted as https://code.google.com/p/go/source/detail?r=e242b6b52827 ***

net/http: increase panic stack trace buffer size from 4 KB to 64 KB.

4 KB is a bit too small in some situations (e.g. panic during a
template execution), and ends up with an unhelpfully-truncated trace.
64 KB should be much more likely to capture the useful information.
There's not a garbage generation issue, since this code should only
be triggered when there's something seriously wrong with the program.

LGTM=bradfitz
R=bradfitz
CC=golang-codereviews
https://codereview.appspot.com/63520043

[gobot, 2014-02-13 23:19:29]

This CL appears to have broken the freebsd-amd64 builder.