[golang-dev] Re: code review 6851061: net/http: fix Transport races & deadlocks (issue 6851061)

This is now ready for review.

It just can't be submitted until Dave's -1 fix is in.

=== RUN TestIssue4191_InfiniteGetTimeout-18
--- PASS: TestIssue4191_InfiniteGetTimeout-18 (0.50 seconds)
=== RUN TestIssue4191_InfiniteGetToPutTimeout-18

jams (also -15 on this machine), which may be related to issue 4434.


https://codereview.appspot.com/6851061/diff/9010/src/pkg/net/http/transport_test.go
File src/pkg/net/http/transport_test.go (right):

https://codereview.appspot.com/6851061/diff/9010/src/pkg/net/http/transport_test.go#newcode917
src/pkg/net/http/transport_test.go:917: }()
Or skip the defer and move ts.Close() to the end, then you get the full
unabridged panic.

https://codereview.appspot.com/6851061/diff/9010/src/pkg/net/http/transport_test.go#newcode946
src/pkg/net/http/transport_test.go:946: t.Errorf("Error issuing GET:
%v", err)
break after t.Errorf

https://codereview.appspot.com/6851061/diff/9010/src/pkg/net/http/transport_test.go#newcode956
src/pkg/net/http/transport_test.go:956: }
ts.Close()

https://codereview.appspot.com/6851061/diff/9010/src/pkg/net/http/transport_test.go#newcode976
src/pkg/net/http/transport_test.go:976: }()
Same as above

https://codereview.appspot.com/6851061/

Hello [email protected], [email protected], [email protected] (cc:
[email protected]),

Please take another look.


http://codereview.appspot.com/6851061/

PTAL

I can't reproduce any hang with any number of GOMAXPROCS (1, 4, 20), but
that's just on my quad-core laptop.


https://codereview.appspot.com/6851061/diff/9010/src/pkg/net/http/transport_test.go
File src/pkg/net/http/transport_test.go (right):

https://codereview.appspot.com/6851061/diff/9010/src/pkg/net/http/transport_test.go#newcode917
src/pkg/net/http/transport_test.go:917: }()
Done.

https://codereview.appspot.com/6851061/diff/9010/src/pkg/net/http/transport_test.go#newcode946
src/pkg/net/http/transport_test.go:946: t.Errorf("Error issuing GET:
%v", err)
Done, even though I do like defers.

https://codereview.appspot.com/6851061/diff/9010/src/pkg/net/http/transport_test.go#newcode951
src/pkg/net/http/transport_test.go:951: t.Errorf("Unexpected successful
copy")
and did a break here too.

https://codereview.appspot.com/6851061/diff/9010/src/pkg/net/http/transport_test.go#newcode956
src/pkg/net/http/transport_test.go:956: }
Done.

https://codereview.appspot.com/6851061/diff/9010/src/pkg/net/http/transport_test.go#newcode976
src/pkg/net/http/transport_test.go:976: }()
Done.

https://codereview.appspot.com/6851061/

So do I, but in this case the defer was interacting badly with the
httptest.Server.Close() method.

LGTM. I'm not sure if you want to wait for a fix for 4434, this test
will break eventually for people like fullung and his stress testing
box.

https://codereview.appspot.com/6851061/

Yeah.


Be sure to put LGTMs on the first line of replies, up at the top before any
quoted section, otherwise codereview.appspot.com and downstream tools don't
see it.

I'm not sure if you want to wait for a fix for 4434, this test
I also plan to run all the Go unit tests on a ~bazillion machines with
varying GOMAXPROCS soonish here, since I'm also getting sick of flakiness.
So I'm fine committing this for now if you're cool with it (and want to
give me a top-line LGTM). I also fixed Issue 4021 which should help
fullung's machine anyway, so net positive maybe? :)

LGTM.

This is my pkg stress testing script

% more ~/stress.bash
#!/bin/bash

set -e
go test -c
PKG=$(basename $(pwd))

while true ; do
export GOMAXPROCS=$[ 1 + $[ RANDOM % 128 ]]
./$PKG.test $@ 2>&1
done


% cd $PKG
% bash ~/stress.bash $TEST_OPTIONS

Hello
I'm waiting for the dust to settle a bit before I start reporting on test
results from the infamous machine again.

There is a minor enhancement to the Go test options that might be useful
for a "test-driven bug data mining" effort:

Allow some kind of random seed that is used to select a random subset of
the Test* functions matched by -run=... and run them in random order with a
random number of repetitions, maybe varying GOMAXPROCS between runs too.

Seed=0 can be the default, which gives the current behaviour of running
everything that matches -test.run=... once. Seed<0 can mean choose a random
seed, which should be printed if -test.v is specified, to allow easier
reproduction in case of a failure.

This is especially useful if you farm out .test binaries to a big group of
machines. And you can farm out normal and -race versions.

There are a few tests that might bang into "too many sockets in TIME_WAIT"
type problems, but mostly it seems that tests should continue to pass under
this extended condition. Those that don't can probably be fixed.

My hope is that this can shake out issues like

http://code.google.com/p/go/issues/detail?id=4423

which I suspect has been lurking for quite a long time.

Cheers

Albert

NOT LGTM.

Sorry, even simple tests in net/http are failing

lucky(~/go/src) % go test net/http
Warning: intentional death for testing
--- FAIL: TestHandlerPanic (5.00 seconds)
serve_test.go:978: expected an error
serve_test.go:985: expected server handler to log an error
Warning: intentional death for testing
--- FAIL: TestHandlerPanicWithHijack (5.00 seconds)
serve_test.go:985: expected server handler to log an error
FAIL
FAIL net/http 18.997s


https://codereview.appspot.com/6851061/

I can't reproduce any failures.

Do you have any local modifications besides 03a6b8c9c396 + 6851061?

LGTM. Very sorry, I had some leftover debugging in net/http/httptest.

PASS
ok net/http 8.499s

I'll wait on submitting this for a bit. I'm still seeing the same GetToPut
hang you did, if I run it in a loop for a bit.

I'd like to see a test which makes that hang more reliable, too.

LGTM as long as dfc is happy


https://codereview.appspot.com/6851061/

Okay, I'll submit this now, since Albert is waiting on reporting high
GOMAXPROCS errors, dfc is working on the net deadline races and LGTMed, and
none of our builders run with high GOMAXPROCS.

And this fixes a long-standing bug that was biting Dustin Sallings (who
reported Issue 4191).

Forward progress....

Yup, worse case the -test.timeout=120 will recover the builder.

*** Submitted as
http://code.google.com/p/go/source/detail?r=be4b8f195c96 ***

net/http: fix Transport races & deadlocks

Thanks to Dustin Sallings for exposing the most frustrating
bug ever, and for providing repro cases (which formed the
basis of the new tests in this CL), and to Dave Cheney and
Dmitry Vyukov for help debugging and fixing.

This CL depends on submited pollster CLs ffd1e075c260 (Unix)
and 14b544194509 (Windows), as well as unsubmitted 6852085.
Some operating systems (OpenBSD, NetBSD, ?) may still require
more pollster work, fixing races (Issue 4434 and
http://goo.gl/JXB6W).

Tested on linux-amd64 and darwin-amd64, both with GOMAXPROCS 1
and 4 (all combinations of which previously failed differently)

Fixes Issue 4191
Update Issue 4434 (related fallout from this bug)

R=dave, bradfitz, dsallings, rsc, fullung
CC=golang-dev
http://codereview.appspot.com/6851061


http://codereview.appspot.com/6851061/

I got the following failure during all.bash on linux/arm but could not
reproduce by running go test -short net/http by hand. Maybe it
happened due to the high load during parallel testing of packages.

Rémy.

panic: test timed out

goroutine 1108 [running]:
testing.alarm()
/storage/remy/go/src/pkg/testing/testing.go:477 +0x60
created by time.goFunc
/storage/remy/go/src/pkg/time/sleep.go:96 +0x54

goroutine 1 [chan receive]:
testing.RunTests(0x10c00, 0x410b58, 0x81, 0x81, 0x10986501, ...)
/storage/remy/go/src/pkg/testing/testing.go:378 +0x6ec
testing.Main(0x10c00, 0x410b58, 0x81, 0x81, 0x40be10, ...)
/storage/remy/go/src/pkg/testing/testing.go:313 +0x68
main.main()
net/http/_test/_testmain.go:311 +0x94

goroutine 2 [runnable]:
created by runtime.main
/storage/remy/go/src/pkg/runtime/proc.c:225

goroutine 3 [timer goroutine (idle)]:
created by addtimer
/storage/remy/go/src/pkg/runtime/ztime_linux_arm.c:73

goroutine 74 [select]:
net/http.(*persistConn).writeLoop(0x109a95a0, 0x410c90)
/storage/remy/go/src/pkg/net/http/transport.go:661 +0x238
created by net/http.(*Transport).getConn
/storage/remy/go/src/pkg/net/http/transport.go:408 +0x5d8

goroutine 31 [syscall]:
syscall.Syscall6()
/storage/remy/go/src/pkg/syscall/asm_linux_arm.s:42 +0x8
syscall.EpollWait(0x7, 0x10989ea8, 0xa, 0xa, 0xffffffff, ...)
/storage/remy/go/src/pkg/syscall/zsyscall_linux_arm.go:327 +0x90
net.(*pollster).WaitFD(0x10989ea0, 0x110c4620, 0x0, 0x0, 0x0, ...)
/storage/remy/go/src/pkg/net/fd_linux.go:146 +0x154
net.(*pollServer).Run(0x110c4620, 0x0)
/storage/remy/go/src/pkg/net/fd_unix.go:211 +0x138
created by net.newPollServer
/storage/remy/go/src/pkg/net/newpollserver_unix.go:33 +0x328

goroutine 58 [select]:
net/http.(*persistConn).writeLoop(0x10964eb0, 0x410ca8)
/storage/remy/go/src/pkg/net/http/transport.go:661 +0x238
created by net/http.(*Transport).getConn
/storage/remy/go/src/pkg/net/http/transport.go:408 +0x5d8

goroutine 89 [semacquire]:
sync.runtime_Semacquire(0x110e3bd0, 0x110e3bd0)
/storage/remy/go/src/pkg/runtime/zsema_linux_arm.c:165 +0x30
sync.(*Cond).Wait(0x110ebec4, 0xb4ae0e3c)
/storage/remy/go/src/pkg/sync/cond.go:73 +0xd0
io.(*pipe).write(0x110ebe80, 0x109b8b90, 0x13, 0x50, 0x0, ...)
/storage/remy/go/src/pkg/io/pipe.go:90 +0x1e8
io.(*PipeWriter).Write(0x110e3bb0, 0x109b8b90, 0x13, 0x50, 0x109b8b90, ...)
/storage/remy/go/src/pkg/io/pipe.go:157 +0x54
net/http.(*populateResponse).Write(0x11110110, 0x109b8b90, 0x13, 0x50,
0x50101, ...)
/storage/remy/go/src/pkg/net/http/filetransport.go:122 +0xa0
fmt.Fprintln(0x1110c6e0, 0x11110110, 0xb4ae0ea0, 0x1, 0x1, ...)
/storage/remy/go/src/pkg/fmt/print.go:280 +0xb0
net/http.Error(0x1110c3e0, 0x11110110, 0x27c63c, 0x12, 0x194, ...)
/storage/remy/go/src/pkg/net/http/server.go:748 +0x15c
net/http.NotFound(0x1110c3e0, 0x11110110)
/storage/remy/go/src/pkg/net/http/server.go:752 +0x50
net/http.serveFile(0x1110c3e0, 0x11110110, 0x11100540, 0x1110c280,
0x110e3d70, ...)
/storage/remy/go/src/pkg/net/http/fs.go:327 +0x1a8
net/http.(*fileHandler).ServeHTTP(0x110e3b90, 0x1110c3e0, 0x11110110,
0x11100540, 0x0, ...)
/storage/remy/go/src/pkg/net/http/fs.go:421 +0x1a4
net/http.func·003(0x110e3b90, 0x110e3ba0, 0x110e3b98, 0x410d2c)
/storage/remy/go/src/pkg/net/http/filetransport.go:43 +0x74
created by net/http.fileTransport.RoundTrip
/storage/remy/go/src/pkg/net/http/filetransport.go:45 +0xd0

goroutine 48 [select]:
net/http.(*persistConn).writeLoop(0x109b8820, 0x0)
/storage/remy/go/src/pkg/net/http/transport.go:661 +0x238
created by net/http.(*Transport).getConn
/storage/remy/go/src/pkg/net/http/transport.go:408 +0x5d8

goroutine 47 [chan receive]:
net/http.(*persistConn).readLoop(0x109b8820, 0x0)
/storage/remy/go/src/pkg/net/http/transport.go:650 +0x5bc
created by net/http.(*Transport).getConn
/storage/remy/go/src/pkg/net/http/transport.go:407 +0x5b0

goroutine 83 [finalizer wait]:
created by runtime.gc
/storage/remy/go/src/pkg/runtime/mgc0.c:961

goroutine 194 [chan receive]:
net/http.(*persistConn).readLoop(0x109b8140, 0x410ea0)
/storage/remy/go/src/pkg/net/http/transport.go:650 +0x5bc
created by net/http.(*Transport).getConn
/storage/remy/go/src/pkg/net/http/transport.go:407 +0x5b0

goroutine 57 [chan receive]:
net/http.(*persistConn).readLoop(0x10964eb0, 0x0)
/storage/remy/go/src/pkg/net/http/transport.go:650 +0x5bc
created by net/http.(*Transport).getConn
/storage/remy/go/src/pkg/net/http/transport.go:407 +0x5b0

goroutine 73 [chan receive]:
net/http.(*persistConn).readLoop(0x109a95a0, 0x76)
/storage/remy/go/src/pkg/net/http/transport.go:650 +0x5bc
created by net/http.(*Transport).getConn
/storage/remy/go/src/pkg/net/http/transport.go:407 +0x5b0

goroutine 113 [chan receive]:
net/http.(*persistConn).readLoop(0x10e78320, 0x410d50)
/storage/remy/go/src/pkg/net/http/transport.go:650 +0x5bc
created by net/http.(*Transport).getConn
/storage/remy/go/src/pkg/net/http/transport.go:407 +0x5b0

goroutine 114 [select]:
net/http.(*persistConn).writeLoop(0x10e78320, 0x0)
/storage/remy/go/src/pkg/net/http/transport.go:661 +0x238
created by net/http.(*Transport).getConn
/storage/remy/go/src/pkg/net/http/transport.go:408 +0x5d8

goroutine 122 [select]:
net/http.(*persistConn).writeLoop(0x10e78b90, 0x410d5c)
/storage/remy/go/src/pkg/net/http/transport.go:661 +0x238
created by net/http.(*Transport).getConn
/storage/remy/go/src/pkg/net/http/transport.go:408 +0x5d8

goroutine 132 [select]:
net/http.(*persistConn).writeLoop(0x10e78c80, 0x410d68)
/storage/remy/go/src/pkg/net/http/transport.go:661 +0x238
created by net/http.(*Transport).getConn
/storage/remy/go/src/pkg/net/http/transport.go:408 +0x5d8

goroutine 116 [chan receive]:
net/http.(*persistConn).readLoop(0x1111bc30, 0x109d4f18)
/storage/remy/go/src/pkg/net/http/transport.go:650 +0x5bc
created by net/http.(*Transport).getConn
/storage/remy/go/src/pkg/net/http/transport.go:407 +0x5b0

goroutine 117 [select]:
net/http.(*persistConn).writeLoop(0x1111bc30, 0x0)
/storage/remy/go/src/pkg/net/http/transport.go:661 +0x238
created by net/http.(*Transport).getConn
/storage/remy/go/src/pkg/net/http/transport.go:408 +0x5d8

goroutine 121 [chan receive]:
net/http.(*persistConn).readLoop(0x10e78b90, 0x0)
/storage/remy/go/src/pkg/net/http/transport.go:650 +0x5bc
created by net/http.(*Transport).getConn
/storage/remy/go/src/pkg/net/http/transport.go:407 +0x5b0

goroutine 131 [chan receive]:
net/http.(*persistConn).readLoop(0x10e78c80, 0x0)
/storage/remy/go/src/pkg/net/http/transport.go:650 +0x5bc
created by net/http.(*Transport).getConn
/storage/remy/go/src/pkg/net/http/transport.go:407 +0x5b0

goroutine 222 [select]:
net/http.(*persistConn).writeLoop(0x10a52780, 0x109d49d0)
/storage/remy/go/src/pkg/net/http/transport.go:661 +0x238
created by net/http.(*Transport).getConn
/storage/remy/go/src/pkg/net/http/transport.go:408 +0x5d8

goroutine 221 [chan receive]:
net/http.(*persistConn).readLoop(0x10a52780, 0x109d4468)
/storage/remy/go/src/pkg/net/http/transport.go:650 +0x5bc
created by net/http.(*Transport).getConn
/storage/remy/go/src/pkg/net/http/transport.go:407 +0x5b0

goroutine 195 [select]:
net/http.(*persistConn).writeLoop(0x109b8140, 0x0)
/storage/remy/go/src/pkg/net/http/transport.go:661 +0x238
created by net/http.(*Transport).getConn
/storage/remy/go/src/pkg/net/http/transport.go:408 +0x5d8

goroutine 299 [chan receive]:
net/http.(*persistConn).readLoop(0x109a92d0, 0x410f48)
/storage/remy/go/src/pkg/net/http/transport.go:650 +0x5bc
created by net/http.(*Transport).getConn
/storage/remy/go/src/pkg/net/http/transport.go:407 +0x5b0

goroutine 273 [chan send]:
net/http.func·009(0x110e3908, 0x110e3920, 0x110e3910, 0x110e3918, 0x0, ...)
/storage/remy/go/src/pkg/net/http/server.go:1271 +0xc0
created by net/http.(*timeoutHandler).ServeHTTP
/storage/remy/go/src/pkg/net/http/server.go:1272 +0x124

goroutine 305 [chan receive]:
net/http.(*persistConn).readLoop(0x110bd690, 0x0)
/storage/remy/go/src/pkg/net/http/transport.go:650 +0x5bc
created by net/http.(*Transport).getConn
/storage/remy/go/src/pkg/net/http/transport.go:407 +0x5b0

goroutine 306 [select]:
net/http.(*persistConn).writeLoop(0x110bd690, 0x0)
/storage/remy/go/src/pkg/net/http/transport.go:661 +0x238
created by net/http.(*Transport).getConn
/storage/remy/go/src/pkg/net/http/transport.go:408 +0x5d8

goroutine 300 [select]:
net/http.(*persistConn).writeLoop(0x109a92d0, 0x410fa8)
/storage/remy/go/src/pkg/net/http/transport.go:661 +0x238
created by net/http.(*Transport).getConn
/storage/remy/go/src/pkg/net/http/transport.go:408 +0x5d8

goroutine 1100 [semacquire]:
sync.runtime_Semacquire(0x13bf7aa0, 0x13bf7aa0)
/storage/remy/go/src/pkg/runtime/zsema_linux_arm.c:165 +0x30
sync.(*WaitGroup).Wait(0x14003768, 0x0)
/storage/remy/go/src/pkg/sync/waitgroup.go:102 +0x11c
net/http/httptest.(*Server).Close(0x14003750, 0x13aed700)
/storage/remy/go/src/pkg/net/http/httptest/server.go:157 +0x68
net/http_test.TestIssue4191_InfiniteGetToPutTimeout(0x147e4900, 0xe)
/storage/remy/go/src/pkg/net/http/transport_test.go:1006 +0x348
testing.tRunner(0x147e4900, 0x411140, 0x0)
/storage/remy/go/src/pkg/testing/testing.go:301 +0xa8
created by testing.RunTests
/storage/remy/go/src/pkg/testing/testing.go:377 +0x6cc

goroutine 597 [syscall]:
syscall.Syscall6()
/storage/remy/go/src/pkg/syscall/asm_linux_arm.s:42 +0x8
syscall.EpollWait(0x33, 0x14359008, 0xa, 0xa, 0xffffffff, ...)
/storage/remy/go/src/pkg/syscall/zsyscall_linux_arm.go:327 +0x90
net.(*pollster).WaitFD(0x14359000, 0x147c18c0, 0x0, 0x0, 0x0, ...)
/storage/remy/go/src/pkg/net/fd_linux.go:146 +0x154
net.(*pollServer).Run(0x147c18c0, 0x13923930)
/storage/remy/go/src/pkg/net/fd_unix.go:211 +0x138
created by net.newPollServer
/storage/remy/go/src/pkg/net/newpollserver_unix.go:33 +0x328

goroutine 603 [syscall]:
syscall.Syscall6()
/storage/remy/go/src/pkg/syscall/asm_linux_arm.s:42 +0x8
syscall.EpollWait(0x35, 0x13d53008, 0xa, 0xa, 0xffffffff, ...)
/storage/remy/go/src/pkg/syscall/zsyscall_linux_arm.go:327 +0x90
net.(*pollster).WaitFD(0x13d53000, 0x147da380, 0x0, 0x0, 0x0, ...)
/storage/remy/go/src/pkg/net/fd_linux.go:146 +0x154
net.(*pollServer).Run(0x147da380, 0x13923930)
/storage/remy/go/src/pkg/net/fd_unix.go:211 +0x138
created by net.newPollServer
/storage/remy/go/src/pkg/net/newpollserver_unix.go:33 +0x328

goroutine 1104 [select]:
net/http.(*persistConn).writeLoop(0x13bd7550, 0x13923930)
/storage/remy/go/src/pkg/net/http/transport.go:661 +0x238
created by net/http.(*Transport).getConn
/storage/remy/go/src/pkg/net/http/transport.go:408 +0x5d8

goroutine 1103 [chan receive]:
net/http.(*persistConn).readLoop(0x13bd7550, 0x13923930)
/storage/remy/go/src/pkg/net/http/transport.go:650 +0x5bc
created by net/http.(*Transport).getConn
/storage/remy/go/src/pkg/net/http/transport.go:407 +0x5b0

goroutine 598 [syscall]:
syscall.Syscall6()
/storage/remy/go/src/pkg/syscall/asm_linux_arm.s:42 +0x8
syscall.EpollWait(0x34, 0x14064008, 0xa, 0xa, 0xffffffff, ...)
/storage/remy/go/src/pkg/syscall/zsyscall_linux_arm.go:327 +0x90
net.(*pollster).WaitFD(0x14064000, 0x1482a5a0, 0x0, 0x0, 0x0, ...)
/storage/remy/go/src/pkg/net/fd_linux.go:146 +0x154
net.(*pollServer).Run(0x1482a5a0, 0x0)
/storage/remy/go/src/pkg/net/fd_unix.go:211 +0x138
created by net.newPollServer
/storage/remy/go/src/pkg/net/newpollserver_unix.go:33 +0x328

goroutine 1102 [chan receive]:
net.(*pollServer).WaitWrite(0x110c4620, 0x13d70070, 0x110c46e0, 0xb)
/storage/remy/go/src/pkg/net/fd_unix.go:251 +0x68
net.(*netFD).Write(0x13d70070, 0x1408eff8, 0x7008, 0x7008, 0x0, ...)
/storage/remy/go/src/pkg/net/fd_unix.go:553 +0x48c
net.(*conn).Write(0x143f1670, 0x1408eff8, 0x7008, 0x7008, 0x10968000, ...)
/storage/remy/go/src/pkg/net/net.go:129 +0xd0
net.(*TCPConn).Write(0x143f1670, 0x1408eff8, 0x7008, 0x7008, 0x8000, ...)
/storage/remy/go/src/pkg/net/dial.go:0 +0x40
bufio.(*Writer).Write(0x13d63ea0, 0x1408eff8, 0x7008, 0x7008, 0xff8, ...)
/storage/remy/go/src/pkg/bufio/bufio.go:488 +0xd0
net/http.(*response).Write(0x14003840, 0x1408e000, 0x8000, 0x8000, 0x8000, ...)
/storage/remy/go/src/pkg/net/http/server.go:507 +0x468
net/http.(*writerOnly).Write(0x143f1a40, 0x1408e000, 0x8000, 0x8000,
0x8000, ...)
/storage/remy/go/src/pkg/net/http/chunked.go:0 +0x74
io.Copy(0x109adb60, 0x143f1a40, 0x110c7500, 0x61, 0x3a8000, ...)
/storage/remy/go/src/pkg/io/io.go:367 +0x25c
net/http.(*response).ReadFrom(0x14003840, 0x110c7500, 0x61, 0x0, 0x0, ...)
/storage/remy/go/src/pkg/net/http/server.go:167 +0x240
io.Copy(0x110d8260, 0x14003840, 0x110c7500, 0x61, 0x0, ...)
/storage/remy/go/src/pkg/io/io.go:357 +0xa4
net/http_test.func·106(0x110d8220, 0x14003840)
/storage/remy/go/src/pkg/net/http/transport_test.go:958 +0xa4
net/http.HandlerFunc.ServeHTTP(0xac6e8, 0x110d8220, 0x14003840,
0x13aed620, 0x26948c, ...)
/storage/remy/go/src/pkg/net/http/server.go:739 +0x40
net/http.(*ServeMux).ServeHTTP(0x13d63e20, 0x110d8220, 0x14003840,
0x13aed620, 0x110d8d60, ...)
/storage/remy/go/src/pkg/net/http/server.go:998 +0x74
net/http/httptest.(*waitGroupHandler).ServeHTTP(0x1464c7a0,
0x110d8220, 0x14003840, 0x13aed620, 0x0, ...)
/storage/remy/go/src/pkg/net/http/httptest/server.go:189 +0xd0
net/http.(*conn).serve(0x13ff42d0, 0x0)
/storage/remy/go/src/pkg/net/http/server.go:702 +0x604
created by net/http.(*Server).Serve
/storage/remy/go/src/pkg/net/http/server.go:1126 +0x4cc
FAIL net/http 120.229s

What value of GOMAXPROCS? goroutine 1102 in the stacks below is the sign of
the expected failure for GOMAXPROCS > 1 until Issue 4434 is fixed.

On Mon, Nov 26, 2012 at 2:34 PM, Rémy Oudompheng
wrote:

I think it was GOMAXPROCS=1 since it was under all.bash and I don't
have particular environment variables.

It's likely the bug still exists with GOMAXPROCS=1 but is just hard to
trigger on relatively fast machines, but your linux/arm triggers it more
easily.

FWIW, I couldn't reproduce that hang running the http tests in a loop on my
linux-amd64 laptop with GOMAXPROCS=1, but it would happen after awhile on
with GOMAXPROCS >1.

I can disable the test if it's not fixed in the next day or so and is
getting annoying.