The g->sched.sp saved stack pointer and the
g->stackbase and g->stackguard stack bounds
can change even while "the world is stopped",
because a goroutine has to call functions (and
therefore might split its stack) when exiting a
system call to check whether the world is stopped
(and if so, wait until the world continues).
That means the garbage collector cannot access
those values safely (without a race) for goroutines
executing system calls. Instead, save a consistent
triple in g->gcsp, g->gcstack, g->gcguard during
entersyscall and have the garbage collector refer
to those.
The old code was occasionally seeing (because of
the race) an sp and stk that did not correspond to
each other, so that stk - sp was not the number of
stack bytes following sp. In that case, if sp < stk
then the call scanblock(sp, stk - sp) scanned too
many bytes (anything between the two pointers,
which pointed into different allocation blocks).
If sp > stk then stk - sp wrapped around.
On 32-bit, stk - sp is a uintptr (uint32) converted
to int64 in the call to scanblock, so a large (~4G)
but positive number. Scanblock would try to scan
that many bytes and eventually fault accessing
unmapped memory. On 64-bit, stk - sp is a uintptr (uint64)
promoted to int64 in the call to scanblock, so a negative
number. Scanblock would not scan anything, possibly
causing in-use blocks to be freed.
In short, 32-bit platforms would have seen either
ineffective garbage collection or crashes during garbage
collection, while 64-bit platforms would have seen
either ineffective or incorrect garbage collection.
You can see the invalid arguments to scanblock in the
stack traces in issue 1620.
Fixes#1620.
Fixes#1746.
R=iant, r
CC=golang-dev
https://golang.org/cl/4437075
runtime: memory allocated by OS not in usable range
runtime: out of memory: cannot allocate 1114112-byte block (2138832896 in use)
throw: out of memory
runtime.throw+0x40 /Users/rsc/g/go/src/pkg/runtime/runtime.c:102
runtime.throw(0x1fffd, 0x101)
runtime.mallocgc+0x2af /Users/rsc/g/go/src/pkg/runtime/malloc.c:60
runtime.mallocgc(0x100004, 0x0, 0x1, 0x1, 0xc093, ...)
runtime.mal+0x40 /Users/rsc/g/go/src/pkg/runtime/malloc.c:289
runtime.mal(0x100004, 0x20bc4)
runtime.new+0x26 /Users/rsc/g/go/src/pkg/runtime/malloc.c:296
runtime.new(0x100004, 0x8fe84000, 0x20bc4)
main.main+0x29 /Users/rsc/x.go:11
main.main()
runtime.mainstart+0xf /Users/rsc/g/go/src/pkg/runtime/386/asm.s:93
runtime.mainstart()
runtime.goexit /Users/rsc/g/go/src/pkg/runtime/proc.c:178
runtime.goexit()
----- goroutine created by -----
_rt0_386+0xbf /Users/rsc/g/go/src/pkg/runtime/386/asm.s:80
R=iant, r
CC=golang-dev
https://golang.org/cl/4444073
Add local URI path support, which isn't as fringe
as I originally thought. (it's supported by Apache)
Send an implicit 302 status on redirects (not 200).
Fixes#1597
R=rsc, r
CC=golang-dev
https://golang.org/cl/4442089
In a GOROOT path a backslash is a path separator
not an escape character. For example, `C:\go`.
Fixes gotest error:
version.go:3: unknown escape sequence: g
R=rsc
CC=golang-dev
https://golang.org/cl/4437076
Fixes#1742.
I hope.
Also this picks up an update to go_tutorial.html that should already have happened.
R=brainman, rsc, peterGo
CC=golang-dev
https://golang.org/cl/4452050
For example, with GOPATH set like so
GOPATH=/home/adg/gocode
And after creating some subdirectories
mkdir /home/adg/gocode/{bin,pkg,src}
I can use goinstall to install the github.com/nf/goto web server,
which depends on the github.com/nf/stat package, with
goinstall github.com/nf/goto
This downloads and installs all dependencies (that aren't already
installed) like so
/home/adg/gocode/bin/goto
/home/adg/gocode/pkg/darwin_amd64/github.com/nf/stat.a
/home/adg/gocode/src/github.com/nf/goto/...
/home/adg/gocode/src/github.com/nf/stat/...
R=rsc, niemeyer
CC=golang-dev
https://golang.org/cl/4438043
I ran the new verification code against a large number of certificates
with a huge (>1000) number of intermediates.
I had previously convinced myself that a cycle in the certificate
graph implied a cycle in the hash graph (and thus, a contradiction).
This is bogus because the signatures don't cover each other.
Secondly, I managed to drive the verification into a time explosion
with a fully connected graph of certificates. The code would try to
walk the factorial number of paths.
This change switches the CertPool to dealing with indexes of
certificates rather than pointers: this makes equality easy. (I didn't
want to compare pointers because a reasonable gc could move objects
around over time.)
Secondly, verification now memorizes the chains from a given
certificate. This is dynamic programming for the lazy, but there's a
solid reason behind it: dynamic programming would ignore the Issuer
hints that we can exploit by walking up the chain rather than down.
R=bradfitzgo
CC=golang-dev
https://golang.org/cl/4439070
Used to fault trying to access l->list->next
when l->list == nil after MCentral_AllocList.
Now prints
runtime: out of memory: no room in arena for 65536-byte allocation (536870912 in use)
throw: out of memory
followed by stack trace.
Fixes#1650.
R=r, dfc
CC=golang-dev
https://golang.org/cl/4446062
This change will allow to generate valid executable,
even if rsc disables dwarf generation, as it happend
at revision 9a64273f9d68.
R=rsc
CC=golang-dev, lvd, vcc
https://golang.org/cl/4425066
Also, 6g was passing uninitialized
Node &n2 to regalloc, causing non-deterministic
register collisions (but only when both left and
right hand side of comparison had function calls).
Fixes#1728.
R=ken2
CC=golang-dev
https://golang.org/cl/4425070
Will fill dashboard down the screen instead of up
when builders get stuck and resume. Already live.
Also delete dead benchmark code.
I think it is safe to say that if/when we bring
benchmarks back, we will use a different
data model.
Fixes#1228.
R=adg
CC=golang-dev
https://golang.org/cl/4449059
This permits the websocket handler to inspect http headers and such.
Fixes#1726.
R=ukai, bradfitz, bradfitzgo
CC=golang-dev
https://golang.org/cl/4439069
Set mailed bit correctly for self-clpatch.
Use repo.rollback correctly.
Allow leading spaces in some C code.
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/4438064
The unexported version returns a sensible default when the user hasn't
set a value. The exported version crashes in that case.
R=bradfitzgo, rsc1
CC=golang-dev
https://golang.org/cl/4435070
The path conversion is done automatically if msys' builtin
shell commands are used.
R=rsc1, peterGo, brainman, Mr_Dark, r
CC=golang-dev
https://golang.org/cl/4452042
