Copy the same sentence from Transport.TLSNextProto.
Change-Id: Ib67bf054e891a68be8ba466a8c52968363374d16
Reviewed-on: https://go-review.googlesource.com/18031
Reviewed-by: Russ Cox <rsc@golang.org>
Currently, if sigprof determines that the G is in user code (not cgo
or libcall code), it will only traceback the G stack if it can acquire
the stack barrier lock. However, it has no such restriction if the G
is in cgo or libcall code. Because cgo calls count as syscalls, stack
scanning and stack barrier installation can occur during a cgo call,
which means sigprof could attempt to traceback a G in a cgo call while
scanstack is installing stack barriers in that G's stack. As a result,
the following sequence of events can cause the sigprof traceback to
panic with "missed stack barrier":
1. M1: G1 performs a Cgo call (which, on Windows, is any system call,
which could explain why this is easier to reproduce on Windows).
2. M1: The Cgo call puts G1 into _Gsyscall state.
3. M2: GC starts a scan of G1's stack. It puts G1 in to _Gscansyscall
and acquires the stack barrier lock.
4. M3: A profiling signal comes in. On Windows this is a global
(though I don't think this matters), so the runtime stops M1 and
calls sigprof for G1.
5. M3: sigprof fails to acquire the stack barrier lock (because the
GC's stack scan holds it).
6. M3: sigprof observes that G1 is in a Cgo call, so it calls
gentraceback on G1 with its Cgo transition point.
7. M3: gentraceback on G1 grabs the currently empty g.stkbar slice.
8. M2: GC finishes scanning G1's stack and installing stack barriers.
9. M3: gentraceback encounters one of the just-installed stack
barriers and panics.
This commit fixes this by only allowing cgo tracebacks if sigprof can
acquire the stack barrier lock, just like in the regular user
traceback case.
For good measure, we put the same constraint on libcall tracebacks.
This case is probably already safe because, unlike cgo calls, libcalls
leave the G in _Grunning and prevent reaching a safe point, so
scanstack cannot run during a libcall. However, this also means that
sigprof will always acquire the stack barrier lock without contention,
so there's no cost to adding this constraint to libcall tracebacks.
Fixes#12528. For 1.5.3 (will require some backporting).
Change-Id: Ia5a4b8e3d66b23b02ffcd54c6315c81055c0cec2
Reviewed-on: https://go-review.googlesource.com/18023
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Russ Cox <rsc@golang.org>
Currently, setNextBarrierPC manipulates the stack barriers without
acquiring the stack barrier lock. This is mostly okay because
setNextBarrierPC also runs synchronously on the G and prevents safe
points, but this doesn't prevent a sigprof from occurring during a
setNextBarrierPC and performing a traceback.
Given that setNextBarrierPC simply sets one entry in the stack barrier
array, this is almost certainly safe in reality. However, given that
this depends on a subtle argument, which may not hold in the future,
and that setNextBarrierPC almost never happens, making it nowhere near
performance-critical, we can simply acquire the stack barrier lock and
be sure that the synchronization will work.
Updates #12528. For 1.5.3.
Change-Id: Ife696e10d969f190157eb1cbe762a2de2ebce079
Reviewed-on: https://go-review.googlesource.com/18022
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Russ Cox <rsc@golang.org>
Update docs on ResponseWriter and Handler around concurrency.
Also add a test.
The Handler docs were old and used "object" a lot. It was also too
ServeMux-centric.
Fixes#13050
Updates #13659 (new issue found in http2 while writing the test)
Change-Id: I25f53d5fa54f1c9d579d3d0f191bf3d94b1a251b
Reviewed-on: https://go-review.googlesource.com/17982
Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
The test for non-package main top-level inputs is done while parsing
the export data. Issue #13468 happened because we were not parsing
the export data when using compiler-generated archives
(that is, when using go tool compile -pack).
Fix this by parsing the export data even for archives.
However, that turns up a different problem: the export data check
reports (one assumes spurious) skew errors now, because it has
not been run since Go 1.2.
(Go 1.3 was the first release to use go tool compile -pack.)
Since the code hasn't run since Go 1.2, it can't be that important.
Since it doesn't work today, just delete it.
Figuring out how to make this code work with Robert's export
format was one of the largest remaining TODOs for that format.
Now we don't have to.
Fixes#13468 and makes the world a better place.
Change-Id: I40a4b284cf140d49d48b714bd80762d6889acdb9
Reviewed-on: https://go-review.googlesource.com/17976
Reviewed-by: Robert Griesemer <gri@golang.org>
Since we allow non-200 responses from HTTPS in normal operation,
it seems odd to reject them in -insecure operation.
Fixes#13037 (again).
Change-Id: Ie232f7544ab192addfad407525888db6b967befe
Reviewed-on: https://go-review.googlesource.com/17945
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
The change here is to move the closeBody call into the if block.
The logging adjustments are just arranging to tell the truth:
in particular if we're not in insecure mode and we get a non-200
error then we do not actually ignore the response
(except as caused by closing the body incorrectly).
As the comment below the change indicates, it is intentional that
we process non-200 pages. The code does process them, because
the if err != nil || status != 200 block does not return.
But that block does close the body, which depending on timing
can apparently poison the later read from the body.
See #13037's initial report:
$ go get -v bosun.org/cmd/bosun/cache
Fetching https://bosun.org/cmd/bosun/cache?go-get=1
ignoring https fetch with status code 404
Parsing meta tags from https://bosun.org/cmd/bosun/cache?go-get=1 (status code 404)
import "bosun.org/cmd/bosun/cache": parsing bosun.org/cmd/bosun/cache: http: read on closed response body
package bosun.org/cmd/bosun/cache: unrecognized import path "bosun.org/cmd/bosun/cache"
The log print about ignoring the https fetch is not strictly true,
since the next thing that happened was parsing the body of that fetch.
But the read on the closed response body failed during parsing.
Moving the closeBody to happen only when we're about to discard the
result and start over (that is, only in -insecure mode) fixes the parse.
At least it should fix the parse. I can't seem to break the parse anymore,
because of #13648 (close not barring future reads anymore),
but this way is clearly better than the old way. If nothing else the old code
closed the body twice when err != nil and -insecure was not given.
Fixes#13037.
Change-Id: Idf57eceb6d5518341a2f7f75eb8f8ab27ed4e0b4
Reviewed-on: https://go-review.googlesource.com/17944
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
This caused #13657.
Reverting fixes#13657.
I was trying to be helpful by fixing #12313,
but I don't need the fix myself.
Will leave for someone with more motivation.
This reverts commit 3e9f063670.
Change-Id: Ifc78a6196f23e0f58e3b9ad7340e207a2d5de0a6
Reviewed-on: https://go-review.googlesource.com/17977
Reviewed-by: Russ Cox <rsc@golang.org>
Patch from Russ.
No bug identified, but I didn't search exhaustively. The new code is
easier to read.
Fixes#13621
Change-Id: Ifda936e4101116fa254ead950b5fe06adb14e977
Reviewed-on: https://go-review.googlesource.com/17981
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
Thanks to @toxeus on GitHub for the test case.
Fixes#12612.
Change-Id: I0c32fbe5044f3552053460a5347c062568093dff
Reviewed-on: https://go-review.googlesource.com/17974
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Also update many call sites where I forgot that the permission
argument is going to be masked by umask.
Fixes#12692.
Change-Id: I52b315b06236122ca020950447863fa396b68abd
Reviewed-on: https://go-review.googlesource.com/17950
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This updates the bundled copy of x/net/http2 to git rev d2ecd08
for https://golang.org/cl/17912 (http2: send client trailers)
and enables the final Trailer test for http2.
Fixes#13557
Change-Id: Iaa15552b82bf7a2cb01b7787a2e1ec5ee680a9d3
Reviewed-on: https://go-review.googlesource.com/17935
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
Also include test for interface state (up or down).
Updates #13606
Change-Id: I03538d65525ddd9c2d0254761861c2df7fc5bd5a
Reviewed-on: https://go-review.googlesource.com/17850
Reviewed-by: Russ Cox <rsc@golang.org>
Reviewed-by: Mikio Hara <mikioh.mikioh@gmail.com>
Run-TryBot: Russ Cox <rsc@golang.org>
This makes go get gitserver/~user/repo.git/foo work.
Fixes#9193.
Change-Id: I8c9d4096903288f7f0e82d6ed1aa78bf038fb81a
Reviewed-on: https://go-review.googlesource.com/17952
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
This doesn't happen enough in the tests to be worth debugging.
Empirically, I expect this to add 5 seconds to the overall 'go test -short cmd/go'
on systems with precise file systems, and nothing on systems without them
(like my Mac).
Fixes#12205.
Change-Id: I0a17cb37bdedcfc0f921c5ee658737f1698c153b
Reviewed-on: https://go-review.googlesource.com/17953
Reviewed-by: Ian Lance Taylor <iant@golang.org>
No test because the code has no test.
Fixes#12313.
Change-Id: I2cfd0a0422c0cd76f0371c2d3bbbdf5bb3b3f1eb
Reviewed-on: https://go-review.googlesource.com/17951
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
This is an attempt to document the current state of signal handling.
It's not intended to describe the best way to handle signals. Future
changes to signal handling should update these docs as appropriate.
update #9896.
Change-Id: I3c50af5cc641357b57dfe90ae1c7883a7e1ec059
Reviewed-on: https://go-review.googlesource.com/17877
Reviewed-by: Russ Cox <rsc@golang.org>
Document that ListenAndServe and ListenAndServeTLS also set TCP
keep-alives.
Fixes#12748
Change-Id: Iba2e8a58dd657eba326db49a6c872e2d972883a4
Reviewed-on: https://go-review.googlesource.com/17681
Reviewed-by: Russ Cox <rsc@golang.org>
Commit dd5e14a751 ensured that no data
could be read for header-only files regardless of what the Header.Size
said. We should document this fact in Reader.Read.
Updates #13647
Change-Id: I4df9a2892bc66b49e0279693d08454bf696cfa31
Reviewed-on: https://go-review.googlesource.com/17913
Reviewed-by: Russ Cox <rsc@golang.org>
With certain names and search domain configurations the
returned error would be one encountered while querying a
generated name instead of the original name. This caused
confusion when a manual check of the same name produced
different results.
Now prefer errors encountered for the original name.
Also makes the low-level DNS connection plumbing swappable
in tests enabling tighter control over responses without
relying on the network.
Fixes#12712
Updates #13295
Change-Id: I780d628a762006bb11899caf20b5f97b462a717f
Reviewed-on: https://go-review.googlesource.com/16953
Reviewed-by: Russ Cox <rsc@golang.org>
Thanks to Albert Hafvenström for the diagnosis.
Fixes#11246.
Change-Id: I2b9e670c0ecf6aa01e5bf4d7a402619e93cc4f4a
Reviewed-on: https://go-review.googlesource.com/17942
Reviewed-by: Ian Lance Taylor <iant@golang.org>
If cgo is turned off, there may not be an external linker available.
Fixes#13450.
Change-Id: Idbf3f3f57b4bb3908b67264f96d276acc952102a
Reviewed-on: https://go-review.googlesource.com/17941
Reviewed-by: Ian Lance Taylor <iant@golang.org>
