From the garbage collector's perspective, time can move backwards in
cgocall. However, in the midst of this time warp, the pointer
arguments to cgocall can go from dead back to live. If a stack growth
happens while they're dead and then a GC happens when they become live
again, GC can crash with a bad heap pointer.
Specifically, the sequence that leads to a panic is:
1. cgocall calls entersyscall, which saves the PC and SP of its call
site in cgocall. Call this PC/SP "X". At "X" both pointer arguments
are live.
2. cgocall calls asmcgocall. Call the PC/SP of this call "Y". At "Y"
neither pointer argument is live.
3. asmcgocall calls the C code, which eventually calls back into the
Go code.
4. cgocallbackg remembers the saved PC/SP "X" in some local variables,
calls exitsyscall, and then calls cgocallbackg1.
5. The Go code causes a stack growth. This stack unwind sees PC/SP "Y"
in the cgocall frame. Since the arguments are dead at "Y", they are
not adjusted.
6. The Go code returns to cgocallbackg1, which calls reentersyscall
with the recorded saved PC/SP "X", so "X" gets stashed back into
gp.syscallpc/sp.
7. GC scans the stack. It sees there's a saved syscall PC/SP, so it
starts the traceback at PC/SP "X". At "X" the arguments are considered
live, so it scans them, but since they weren't adjusted, the pointers
are bad, so it panics.
This issue started as of commit ca4089ad, when the compiler stopped
marking arguments as live for the whole function.
Since this is a variable liveness issue, fix it by adding KeepAlive
calls that keep the arguments live across this whole time warp.
The existing issue7978 test has all of the infrastructure for testing
this except that it's currently up to chance whether a stack growth
happens in the callback (it currently only happens on the
linux-amd64-noopt builder, for example). Update this test to force a
stack growth, which causes it to fail reliably without this fix.
Fixes#17785.
Change-Id: If706963819ee7814e6705693247bcb97a6f7adb8
Reviewed-on: https://go-review.googlesource.com/33710
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Be consistent with the argument names already provided. Also
parameter is the variable, argument is the value.
Fixes#18099
Change-Id: Idb3f4e9ffc214036c721ddb4f614ec6c95bb7778
Reviewed-on: https://go-review.googlesource.com/33660
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
The code was intended to test that mux handler should redirect at
most once, but the added loop condition defeated that. Remove the
loop condition and document the intention better.
Fixes#18068.
Change-Id: I2a4ea041eae27168b45a09aa46e740ac03921594
Reviewed-on: https://go-review.googlesource.com/33654
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
None of them need to be called out in the release notes.
Change-Id: I143a1879b25063574e4107c1e89264434d45d1d5
Reviewed-on: https://go-review.googlesource.com/33676
Reviewed-by: Ian Lance Taylor <iant@golang.org>
As discussed in #18095 the server should not log for bad user input.
Change-Id: I628a796926eff3a971e5b04abec17ea377c3f9b7
Reviewed-on: https://go-review.googlesource.com/33617
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Expand myhostname fallback detection to properly detect the local
hostname in addition to other supported special names and suffixes.
Fixes#17967
Change-Id: I1fe141fd9838b25886c08b6f2fd325e58be60457
Reviewed-on: https://go-review.googlesource.com/33550
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
The doc field is not yet used - remove it for now (we may end up
with a different solution for 1.9). This reduces memory consumption
for parsing all of std lib by about 40MB and makes parsing slightly
faster.
Change-Id: Iafb00b9c7f1be9c66fdfb29096d3da5049b2fcf5
Reviewed-on: https://go-review.googlesource.com/33661
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
When context methods were initially added it was attempted to unify
behavior between drivers without Context methods and those with
Context methods to always return right away when the Context expired.
However in doing so the driver call could be executed outside of the
scope of the driver connection lock and thus bypassing thread safety.
The new behavior waits until the driver operation is complete. It then
checks to see if the context has expired and if so returns that error.
Change-Id: I4a5c7c3263420c57778f36a5ed6fa0ef8cb32b20
Reviewed-on: https://go-review.googlesource.com/32422
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Also refactor common position filling code into a function.
Fixes#18011
Change-Id: I76528626da67a7309193fa92af1e361c8e2fcf84
Reviewed-on: https://go-review.googlesource.com/33631
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Skip lines if they are empty or starting with "#" which are valid
legacy pprof output format.
Fixes#18025
Change-Id: I7aee439171496932637b8ae3188700911f569b16
Reviewed-on: https://go-review.googlesource.com/33454
Reviewed-by: Peter Weinberger <pjw@google.com>
Android's libc doesn't provide access to auxv, so currently the Go
runtime synthesizes a fake, minimal auxv when loaded as a library on
Android. This used to be sufficient, but now we depend on auxv to
retrieve the system physical page size and panic if we can't retrieve
it.
Fix this by falling back to reading auxv from /proc/self/auxv if the
loader-provided auxv is empty and removing the synthetic auxv vectors.
Fixes#18041.
Change-Id: Ia2ec2c764a6609331494a5d359032c56cbb83482
Reviewed-on: https://go-review.googlesource.com/33652
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Tested by running
GOTRACEBACK=2 CGO_CFLAGS="-Wa,--elf-stt-common=yes" go test -ldflags=-linkmode=internal
in misc/cgo/test. That failed before this CL, succeeded after.
I don't think it's worth doing that as a regular test, though,
especially since only recent versions of the GNU binutils support the
--elf-stt-common option.
Fixes#18088.
Change-Id: I893d86181faee217b1504c054b0ed3f7c8d977d3
Reviewed-on: https://go-review.googlesource.com/33653
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Go 1.5 worked with Unicode console input but not ^Z.
Go 1.6 did not work with Unicode console input but did handle one ^Z case.
Go 1.7 did not work with Unicode console input but did handle one ^Z case.
The intent of this CL is for Go 1.8 to work with Unicode console input
and also handle all ^Z cases.
Here's a simple test program for reading from the console.
It prints a "> " prompt, calls read, prints what it gets, and repeats.
package main
import (
"fmt"
"os"
)
func main() {
p := make([]byte, 100)
fmt.Printf("> ")
for {
n, err := os.Stdin.Read(p)
fmt.Printf("[%d %q %v]\n> ", n, p[:n], err)
}
}
On Unix, typing a ^D produces a break in the input stream.
If the ^D is at the beginning of a line, then the 0 bytes returned
appear as an io.EOF:
$ go run /tmp/x.go
> hello
[6 "hello\n" <nil>]
> hello^D[5 "hello" <nil>]
> ^D[0 "" EOF]
> ^D[0 "" EOF]
> hello^Dworld
[5 "hello" <nil>]
> [6 "world\n" <nil>]
>
On Windows, the EOF character is ^Z, not ^D, and there has
been a long-standing problem that in Go programs, ^Z on Windows
does not behave in the expected way, namely like ^D on Unix.
Instead, the ^Z come through as literal ^Z characters:
C:\>c:\go1.5.4\bin\go run x.go
> ^Z
[3 "\x1a\r\n" <nil>]
> hello^Zworld
[13 "hello\x1aworld\r\n" <nil>]
>
CL 4310 attempted to fix this bug, then known as #6303,
by changing the use of ReadConsole to ReadFile.
This CL was released as part of Go 1.6 and did fix the case
of a ^Z by itself, but not as part of a larger input:
C:\>c:\go1.6.3\bin\go run x.go
> ^Z
[0 "" EOF]
> hello^Zworld
[13 "hello\x1aworld\r\n" <nil>]
>
So the fix was incomplete.
Worse, the fix broke Unicode console input.
ReadFile does not handle Unicode console input correctly.
To handle Unicode correctly, programs must use ReadConsole.
Early versions of Go used ReadFile to read the console,
leading to incorrect Unicode handling, which was filed as #4760
and fixed in CL 7312053, which switched to ReadConsole
and was released as part of Go 1.1 and still worked as of Go 1.5:
C:\>c:\go1.5.4\bin\go run x.go
> hello
[7 "hello\r\n" <nil>]
> hello world™
[16 "hello world™\r\n" <nil>]
>
But in Go 1.6:
C:\>c:\go1.6.3\bin\go run x.go
> hello
[7 "hello\r\n" <nil>]
> hello world™
[0 "" EOF]
>
That is, changing back to ReadFile in Go 1.6 reintroduced #4760,
which has been refiled as #17097. (We have no automated test
for this because we don't know how to simulate console input
in a test: it appears that one must actually type at a keyboard
to use the real APIs. This CL at least adds a comment warning
not to reintroduce ReadFile again.)
CL 29493 attempted to fix#17097, but it was not a complete fix:
the hello world™ example above still fails, as does Shift-JIS input,
which was filed as #17939.
CL 29493 also broke ^Z handling, which was filed as #17427.
This CL attempts the never before successfully performed trick
of simultaneously fixing Unicode console input and ^Z handling.
It changes the console input to use ReadConsole again,
as in Go 1.5, which seemed to work for all known Unicode input.
Then it adds explicit handling of ^Z in the input stream.
(In the case where standard input is a redirected file, ^Z processing
should not happen, and it does not, because this code path is only
invoked when standard input is the console.)
With this CL:
C:\>go run x.go
> hello
[7 "hello\r\n" <nil>]
> hello world™
[16 "hello world™\r\n" <nil>]
> ^Z
[0 "" EOF]
> [2 "\r\n" <nil>]
> hello^Zworld
[5 "hello" <nil>]
> [0 "" EOF]
> [7 "world\r\n" <nil>]
This almost matches Unix:
$ go run /tmp/x.go
> hello
[6 "hello\n" <nil>]
> hello world™
[15 "hello world™\n" <nil>]
> ^D
[0 "" EOF]
> [1 "\n" <nil>]
> hello^Dworld
[5 "hello" <nil>]
> [6 "world\n" <nil>]
>
The difference is in the handling of hello^Dworld / hello^Zworld.
On Unix, hello^Dworld terminates the read of hello but does not
result in a zero-length read between reading hello and world.
This is dictated by the tty driver, not any special Go code.
On Windows, in this CL, hello^Zworld inserts a zero length read
result between hello and world, which is treated as an interior EOF.
This is implemented by the Go code in this CL, but it matches the
handling of ^Z on the console in other programs:
C:\>copy con x.txt
hello^Zworld
1 file(s) copied.
C:\>type x.txt
hello
C:\>
A natural question is how to test all this. As noted above, we don't
know how to write automated tests using the actual Windows console.
CL 29493 introduced the idea of substituting a different syscall.ReadFile
implementation for testing; this CL continues that idea but substituting
for syscall.ReadConsole instead. To avoid the regression of putting
ReadFile back, this CL adds a comment warning against that.
Fixes#17427.
Fixes#17939.
Change-Id: Ibaabd0ceb2d7af501d44ac66d53f64aba3944142
Reviewed-on: https://go-review.googlesource.com/33451
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Quentin Smith <quentin@golang.org>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Fixes the os test on the Android builder.
Change-Id: Ibb9db712156a620fcccf515e035475c5e2f535a5
Reviewed-on: https://go-review.googlesource.com/33650
Run-TryBot: David Crawshaw <crawshaw@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
The pprof code discards all heap allocations made by runtime
routines. This caused it to discard heap allocations made by functions
called by reflect.Call, as the calls are made via the functions
`runtime.call32`, `runtime.call64`, etc. Fix the profiler to retain
these heap allocations.
Fixes#18077.
Change-Id: I8962d552f1d0b70fc7e6f7b2dbae8d5bdefb0735
Reviewed-on: https://go-review.googlesource.com/33635
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Document that key in Header.Get(key) is case insensitive in
http.Header, mail.Header, textproto.Header.
Fixes#18019
Change-Id: Iba7932491e02e555190b6fce053088b580a853ef
Reviewed-on: https://go-review.googlesource.com/33530
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
The element index needs to be placed in From3. Before this CL it
was impossible to write a VSTE instruction that could be
successfully parsed, so this won't affect existing assembly code.
Fixes#18075.
Change-Id: I5b71be4c6632b1d5a30820a529122f96fd1bc864
Reviewed-on: https://go-review.googlesource.com/33584
Run-TryBot: Michael Munday <munday@ca.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Bill O'Farrell <billotosyr@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
The TestMain docs explain that flag.Parse() should be called if TestMain
itself depends on command-line flags.
The issue here is that the example implementation does not use any
flags, and thus the flag.Parse call is unnecessary. This leads to people
who use this example as a starting point for their own implementations
to forget that the call is not necessary in most cases.
Comment it out instead of removing the line to keep it as a reminder, as
suggested by Minux Ma.
Change-Id: I6ffc5413e7036366ae3cf0f069b7065e832a3b45
Reviewed-on: https://go-review.googlesource.com/33273
Reviewed-by: Minux Ma <minux@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Or they can use sql.Param instead.
Change-Id: Icf21dbcc87170635c3f5d3f49736429a37abe9da
Reviewed-on: https://go-review.googlesource.com/33576
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Daniel Theophanes <kardianos@gmail.com>
Reviewed-by: Minux Ma <minux@golang.org>
When transitioning from C code to Go code we must respect the C
calling convention. On s390x this means that r6-r13, r15 and f8-f15
must be saved and restored by functions that use them.
On s390x we were saving the wrong set of floating point registers
(f0, f2, f4 and f6) rather than f8-f15 which means that Go code
could clobber registers that C code expects to be restored. This
CL modifies the crosscall functions on s390x to save/restore the
correct floating point registers.
Fixes#18035.
Change-Id: I5cc6f552c893a4e677669c8891521bf735492e97
Reviewed-on: https://go-review.googlesource.com/33571
Reviewed-by: Ian Lance Taylor <iant@golang.org>
It was supposed to be testing SSA, not amd64.
For #18024
Change-Id: Ibe65d7eb6bed9bc4b3eda68e1eaec5fa39fe8f76
Reviewed-on: https://go-review.googlesource.com/33491
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
There is some code value too: types intending to implement
Source64 can write a conversion confirming that.
For #4254 and the Go 1.8 release notes.
Change-Id: I7fc350a84f3a963e4dab317ad228fa340dda5c66
Reviewed-on: https://go-review.googlesource.com/33456
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
