Currently only the rwmutex write lock prevents descheduling. The read
lock does not. This leads to the following situation:
1. A reader acquires the lock and gets descheduled.
2. GOMAXPROCS writers attempt to acquire the lock (or at least one
writer does, followed by readers). This blocks all of the Ps.
3. There is no 3. The descheduled reader never gets to run again
because there are no Ps, so it never releases the lock and the system
deadlocks.
Fix this by preventing descheduling while holding the read lock. This
requires also rewriting TestParallelRWMutexReaders to always create
enough GOMAXPROCS and to use non-blocking operations for
synchronization.
Fixes#20903.
Change-Id: Ibd460663a7e5a555be5490e13b2eaaa295fac39f
Reviewed-on: https://go-review.googlesource.com/47632
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
ResolveTCPAddr, ResolveUDPAddr, and ResolveIPAddr return at most one
address. When given a name like "golang.org" to resolve that might
have more than 1 address, the net package has historically preferred
IPv4 addresses, with the assumption that many users don't yet have
IPv6 connectivity and randomly selecting between an IPv4 address and
an IPv6 address at runtime wouldn't be a good experience for IPv4-only
users.
In CL 45088 (78cf0e56) I modified the resolution of the
unspecified/empty address to internally resolve to both IPv6 "::" and
0.0.0.0 to fix issue #18806.
That code has 3 other callers I hadn't considered, though: the
Resolve*Addr functions. Since they preferred IPv4, any Resolve*Addr of
"[::]:port" or "::" (for ResolveIPAddr) would internally resolve both
"::" and 0.0.0.0 and then prefer 0.0.0.0, even though the user was
looking up an IPv6 literal.
Add tests and fix it, not by undoing the fix to #18806 but by
selecting the preference function for Resolve*Addr more explicitly: we
still prefer IPv4, but if the address being looked up was an IPv6
literal, prefer IPv6.
The tests are skipped on machines without IPv6.
Fixes#20911
Change-Id: Ib7036cc43182ae4118cd1390c254e17c04a251a3
Reviewed-on: https://go-review.googlesource.com/47554
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
The text before CL 45816 was:
-timeout t
If a test runs longer than t, panic.
The default is 10 minutes (10m).
CL 45816 was supposed to be about clarifying test vs test binary,
and it did add the clarification of referring to "duration d",
but it also introduced incorrect text about timeout 0.
The new text in this CL preserves the good change and
eliminates the incorrect one:
-timeout d
If a test binary runs longer than duration d, panic.
The default is 10 minutes (10m).
For #14780.
Change-Id: I4f79d6e48ed9295bc9f34a36aa90d3b03b40d7f5
Reviewed-on: https://go-review.googlesource.com/47571
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Following the spec clarification in CL 40393, copy that text
to reflect docs to state that the initial capacity of MakeMapWithSize
is a hint/approximate.
Fixes#19903
Change-Id: I6b3315b8183cafaa61fbb2839a4e42b76fd71544
Reviewed-on: https://go-review.googlesource.com/46270
Reviewed-by: Robert Griesemer <gri@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
Go 1.9 beta 2 is already out.
It's too late to break code with a change like this.
This can be rolled forward for Go 1.10.
This reverts commit ae238688d2.
Change-Id: Ib67b8629e3deac5d50d76581aba6a91ca7a7853e
Reviewed-on: https://go-review.googlesource.com/47570
Reviewed-by: Russ Cox <rsc@golang.org>
The name LabelList was changed to LabelSet during the development of the
proposal [1], except in one function comment. This commit fixes that.
Fixes#20905.
[1] https://github.com/golang/go/issues/17280
Change-Id: Id4f48d59d7d513fa24b2e42795c2baa5ceb78f36
Reviewed-on: https://go-review.googlesource.com/47470
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
mheap.allocLarge just calls bestFitTreap and is the only caller of
bestFitTreap. Flatten these into a single function. Also fix their
comments: allocLarge claims to return exactly npages but can in fact
return a larger span, and h.freelarge is not in fact indexed by span
start address.
Change-Id: Ia20112bdc46643a501ea82ea77c58596bc96f125
Reviewed-on: https://go-review.googlesource.com/47315
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
The Server struct has exported fields, which allows users to manually
create a Server object without using using NewServer or NewTLSServer
and directly call Start or StartTLS on their object.
In order to ensure that manual creation of Server works, the
NewUnstartedServer function should not initialize Server in any way
that the user was not able to do themselves. For example, the setting
of a unexported filed, client, is not something a user can do.
Thus, rather than setting the client field in NewUnstartedServer,
we lazily initialize it when Start or StartTLS is called.
Otherwise, the Server logic can nil panic later when it assumes that this
field has been initialized.
Fixes#20871
Change-Id: I65c6a9f893ea963b0fbad0990b33af08007c1140
Reviewed-on: https://go-review.googlesource.com/47353
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
The Func type has allowed calling the Func.Name method on a nil pointer
since Go1.2, where it returned an empty string. A regression caused by
CL/37331 caused this behavior to change. This breaks code that lazily
does runtime.FuncForPC(myPtr).Name() without first checking that myPtr
is actually non-nil.
Fixes#20872
Change-Id: Iae9a2ebabca5e9d1f5a2cdaf2f30e9c6198fec4f
Reviewed-on: https://go-review.googlesource.com/47354
Reviewed-by: Marvin Stenger <marvin.stenger94@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Wrong instructions "MOVW 8(F0), R1" and "MOVW R0<<0(F1), R1"
are silently accepted, and all Fx are treated as Rx.
The patch checks all those illegal base registers.
fixes#20724
Change-Id: I05d41bb43fe774b023205163b7daf4a846e9dc88
Reviewed-on: https://go-review.googlesource.com/46132
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
If a retryable error such as EAGAIN/EINTR is encountered during a call
to sendfile(), we should not assume that a partial write occurred.
Instead, just like any other platform, we should always try again even
if 0 bytes were written.
Fixes#20857
Change-Id: I9aa48d193c27c6794c550320da4d3f7544041f37
Reviewed-on: https://go-review.googlesource.com/47351
Run-TryBot: Shawn Walker-Salas <shawn.walker@oracle.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
The current code calculates register number incorrectly.
The fix corrects the register number calculation.
Add cases created by decoder to test assembler.
Fixes#20697Fixes#20723
Change-Id: I73ac153df9ea9f51c43a5104828d7a5389551c92
Reviewed-on: https://go-review.googlesource.com/45850
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Now that ReadMemStats is fast (CL 34937), CL 36791 is not so
necessary, and causes confusion. See #20863
This was already partially reverted in CL 46612 but missed two of the
spots.
Fixes#20863
Change-Id: I1307a0f7b1f9e86e8b6ceaa6a677f24f13431110
Reviewed-on: https://go-review.googlesource.com/47350
Reviewed-by: Austin Clements <austin@google.com>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Document that the byte value returned by ReadByte() is meaningless
if its error != nil. Because io.Reader and io.ByteReader are similar in
name, this CL aims to clear up any ambiguity surrounding the returned
values, particularly where io.Reader is allowed to return both a
non-zero number of valid bytes and err == EOF.
Fixes#20825
Change-Id: I3a23c18c80c471c0caae3b4d2f6f8e547da0bed9
Reviewed-on: https://go-review.googlesource.com/46950
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
FreeBSD 9.3.
Add Linux arm64. (required second line)
Clarify glibc requirement now that we have second line in notes.
OS X to macOS
Updates #20850
Change-Id: I684d464ed32a072081726b7c805a346c22c42f97
Reviewed-on: https://go-review.googlesource.com/47252
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Apparently, "all such calls must happen" means that the t.Run call
must *return* before the outer test function returns, or the calls
will cause a data race on t.ran.
Clarify the docs.
Fixes#20339
Change-Id: I191a9af2a9095be1e0aaf10b79c30e00a9c495cb
Reviewed-on: https://go-review.googlesource.com/47150
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Apply code review suggestion from CL 46715.
The block is doing more than just checking len(r.certs) == len(tc.cns).
It also verifies that certificate common names match.
Change-Id: I28d6926a5da48bd8f6c80aa5e5a1ed6d4990f845
Reviewed-on: https://go-review.googlesource.com/47132
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Updates http2 to x/net/http2 git rev d4223d6710a for:
http2: refund connection flow control on DATA frames received after reset
https://golang.org/cl/46591Fixes#46591
Change-Id: I5e6999599e921fed279c6d29ae77439191e99615
Reviewed-on: https://go-review.googlesource.com/47096
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Tom Bergan <tombergan@google.com>
And some double space after period cleanup while I'm here.
I guess my previous regexps missed these. My next cleaner should
probably use go/ast instead of perl.
Updates #20221
Change-Id: Idb051e7ac3a7fb1fb86e015f709e32139d065d92
Reviewed-on: https://go-review.googlesource.com/47094
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
Currently the execLock is a mutex, which has the unfortunate
side-effect of serializing all thread creation. This replaces it with
an rwmutex so threads can be created in parallel, but exec still
blocks thread creation.
Fixes#20738.
Change-Id: Ia8f30a92053c3d28af460b0da71176abe5fd074b
Reviewed-on: https://go-review.googlesource.com/47072
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Currently runtime.rwmutex is written to block the calling goroutine
rather than the calling thread. However, rwmutex was intended to be
used in the scheduler, which means it needs to be a thread-level
synchronization primitive.
Hence, this modifies rwmutex to synchronize threads instead of
goroutines. This has the consequence of making it write-barrier-free,
which is also important for using it in the scheduler.
The implementation makes three changes: it replaces the "w" semaphore
with a mutex, since this was all it was being used for anyway; it
replaces "writerSem" with a single pending M that parks on its note;
and it replaces "readerSem" with a list of Ms that park on their notes
plus a pass count that together emulate a counting semaphore. I
model-checked the safety and liveness of this implementation through
>1 billion schedules.
For #20738.
Change-Id: I3cf5a18c266a96a3f38165083812803510217787
Reviewed-on: https://go-review.googlesource.com/47071
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Prevent possible goroutine rescheduling to another P between
Put and Get calls by locking the goroutine to OS thread.
Inspired by the CL 42770.
Fixes#20198.
Change-Id: I18e24fcad1630658713e6b9d80d90d7941f604be
Reviewed-on: https://go-review.googlesource.com/44310
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
If the only way the user indicates they want alloc stats shown
is via ReportAllocs, we don't know that until benchFunc is run.
Therefore, StopTimer's ReadMemStats will return incorrect data
for single cycle runs since there's no counterpart ReadMemStats from
StartTimer that initializes alloc stats.
It appears that this bug was introduced by CL 46612,
"testing: only call ReadMemStats if necessary when benchmarking"
Fixes#20590
Change-Id: I3b5ef91677823f4b98011880a3be15423baf7e33
Reviewed-on: https://go-review.googlesource.com/46612
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
The test added for issue #18146 exposed a long-existing bug in the
Solaris port; notably, that syscall.Exec uses RawSyscall -- which is not
actually functional for the Solaris port (intentionally) and only exists
as a placebo to satisfy build requirements.
Call syscall.execve instead for Solaris.
Fixes#20832
Change-Id: I327d863f4bbbbbb6e5ecf66b82152c4030825d09
Reviewed-on: https://go-review.googlesource.com/47032
Run-TryBot: Shawn Walker-Salas <shawn.walker@oracle.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
os.Chmod returns an error when passed a long path (>=260) characters on
Windows. CL 32451 fixed most file functions in os. This change applies the
same fix to os.Chmod.
Fixes#20829
Change-Id: I3270db8317ce6e06e6d77070a32a5df6ab2491e0
Reviewed-on: https://go-review.googlesource.com/47010
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
A common task is trying to get today's date in the local time zone
with zero values for the hour, minute, second, and nanosecond fields.
I tried this recently and incorrectly used Truncate(24*time.Hour),
which truncates based on a UTC clock, and gave me 5pm Pacific time
instead of midnight Pacific.
I thought it would be helpful to show a "correct" way to do this.
Change-Id: I479e6b0cc56367068530981ca69882b34febf945
Reviewed-on: https://go-review.googlesource.com/46833
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
