For reasons unknown, SIGUSR1 appears to be blocked at process start
for tests on the android-arm-corellium and android-arm64-corellium
builders. (This has been observed before, too: see CL 203957.)
Make the test resilient to blocked signals by always calling Notify
and waiting for potential signal delivery after sending any signal
that is not known to be unblocked.
Also remove the initial SIGWINCH signal from testCancel. The behavior
of an unhandled SIGWINCH is already tested in TestStop, so we don't
need to re-test that same case: waiting for an unhandled signal takes
a comparatively long time (because we necessarily don't know when it
has been delivered), so this redundancy makes the overall test binary
needlessly slow, especially since it is called from both TestReset and
TestIgnore.
Since each signal is always unblocked while we have a notification
channel registered for it, we don't need to modify any other tests:
TestStop and testCancel are the only functions that send signals
without a registered channel.
Fixes#38165
Updates #33174
Updates #15661
Change-Id: I215880894e954b62166024085050d34323431b63
Reviewed-on: https://go-review.googlesource.com/c/go/+/226461
Run-TryBot: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
In CL 226138, I updated TestStop to have more uniform behavior for its signals.
However, that test seems to always fail for SIGUSR1 on the Android ARM builders.
I'm not sure what's special about Android for this particular case,
but let's skip the test to unbreak the builders while I investigate.
For #38165
Updates #33174
Change-Id: I35a70346cd9757a92acd505a020bf95e6871405c
Reviewed-on: https://go-review.googlesource.com/c/go/+/226458
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Use a uniform function (named “quiesce”) to wait for possible signals
in a way that gives the kernel many opportunities to deliver them.
Simplify channel usage and concurrency in stress tests.
Use (*testing.T).Deadline instead of parsing the deadline in TestMain.
In TestStop, sleep forever in a loop if we expect the test to die from
a signal. That should reduce the flakiness of TestNohup, since
TestStop will no longer spuriously pass when run as a subprocess of
TestNohup.
Since independent signals should not interfere, run the different
signals in TestStop in parallel when testing in short mode.
Since TestNohup runs TestStop as a subprocess, and TestStop needs to
wait many times for signals to quiesce, run its test subprocesses
concurrently and in short mode — reducing the latency of that test by
more than a factor of 2.
The above two changes reduce the running time of TestNohup on my
workstation to ~345ms, making it possible to run much larger counts of
the test in the same amount of wall time. If the test remains flaky
after this CL, we can spend all or part of that latency improvement on
a longer settle time.
Updates #33174
Change-Id: I09206f213d8c1888b50bf974f965221a5d482419
Reviewed-on: https://go-review.googlesource.com/c/go/+/226138
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Fixes#35085
Change-Id: Ice611e1223392f687061a43fd4c2298ea22774fb
Reviewed-on: https://go-review.googlesource.com/c/go/+/207081
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
Now that the runtime can send preemption signals, it is possible that
a channel that asks for all signals can see both SIGURG and SIGHUP
before reading either, in which case one of the signals will be dropped.
We have to use a larger buffer so that the test see the signal it expects.
Fixes#35466
Change-Id: I36271eae0661c421780c72292a5bcbd443ada987
Reviewed-on: https://go-review.googlesource.com/c/go/+/206257
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
This adds support for pausing a running G by sending a signal to its
M.
The main complication is that we want to target a G, but can only send
a signal to an M. Hence, the protocol we use is to simply mark the G
for preemption (which we already do) and send the M a "wake up and
look around" signal. The signal checks if it's running a G with a
preemption request and stops it if so in the same way that stack check
preemptions stop Gs. Since the preemption may fail (the G could be
moved or the signal could arrive at an unsafe point), we keep a count
of the number of received preemption signals. This lets stopG detect
if its request failed and should be retried without an explicit
channel back to suspendG.
For #10958, #24543.
Change-Id: I3e1538d5ea5200aeb434374abb5d5fdc56107e53
Reviewed-on: https://go-review.googlesource.com/c/go/+/201760
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Previously, TestAtomicStop used a hard-coded 2-second timeout.
That empirically is not long enough on certain builders. Rather than
adjusting it to a different arbitrary value, use a slice of the
overall timeout for the test binary. If everything is working, we
won't block nearly that long anyway.
Updates #35085
Change-Id: I7b789388e3152413395088088fc497419976cf5c
Reviewed-on: https://go-review.googlesource.com/c/go/+/203499
Run-TryBot: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
On ARM and ARM64, during a VDSO call, the g register may be
temporarily clobbered by the VDSO code. If a signal is received
during the execution of VDSO code, we may not find a valid g
reading the g register. In CL 192937, we conservatively assume
g is nil. But this approach has a problem: we cannot handle
the signal in this case. Further, if the signal is not a
profiling signal, we'll call badsignal, which calls needm, which
wants to get an extra m, but we don't have one in a non-cgo
binary, which cuases the program to hang.
This is even more of a problem with async preemption, where we
will receive more signals than before. I ran into this problem
while working on async preemption support on ARM64.
In this CL, before making a VDSO call, we save the g on the
gsignal stack. When we receive a signal, we will be running on
the gsignal stack, so we can fetch the g from there and move on.
We probably want to do the same for PPC64. Currently we rely on
that the VDSO code doesn't actually clobber the g register, but
this is not guaranteed and we don't have control with.
Idea from discussion with Dan Cross and Austin.
Should fix#34391.
Change-Id: Idbefc5e4c2f4373192c2be797be0140ae08b26e3
Reviewed-on: https://go-review.googlesource.com/c/go/+/202759
Run-TryBot: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Austin Clements <austin@google.com>
Try to deflake TestNohup.
The kernel will deliver a signal as a thread returns from a syscall.
If the only active thread is sleeping, and the system is busy,
the kernel may not get around to waking up a thread to catch the signal.
Try splitting up the sleep, to give the kernel another change to deliver.
I don't know if this will help, but it seems worth a try.
Fixes#33174
Change-Id: I34b3240af706501ab8538cb25c4846d1d30d7691
Reviewed-on: https://go-review.googlesource.com/c/go/+/194879
Reviewed-by: Bryan C. Mills <bcmills@google.com>
This increases the time to wait from 1 to 2 seconds in the
TestAtomicStop testcase. When running with gccgo on ppc64
& ppc64le on a loaded systems these testcases can
intermittently fail with the current value.
Updates #29046
Change-Id: If420274dd65926d933a3024903b5c757c300bd60
Reviewed-on: https://go-review.googlesource.com/c/153826
Run-TryBot: Lynn Boger <laboger@linux.vnet.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Ignored reports whether sig is currently ignored.
This implementation only works applies on Unix systems for now. However, at
the moment that is also the case for Ignore() and several other signal
interaction methods, so that seems fair.
Fixes#22497
Change-Id: I7c1b1a5e12373ca5da44709500ff5acedc6f1316
Reviewed-on: https://go-review.googlesource.com/108376
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Otherwise we may delay the delivery of these signals for an arbitrary
length of time. We are already careful to not block signals that the
program has asked to see.
Also make sure that we don't miss a signal delivery if a thread
decides to stop for a while while executing the signal handler.
Also clean up the TestAtomicStop output a little bit.
Fixes#21433
Change-Id: Ic0c1a4eaf7eba80d1abc1e9537570bf4687c2434
Reviewed-on: https://go-review.googlesource.com/79581
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
CL 44352 changed the behavior of SIGINT, which can break tests that
themselves use SIGINT. I think we can only implement this if the
testing package has a way to know whether the code under test is using
SIGINT, but os/signal does not provide an API for that. Roll back for
1.9 and think about this again for 1.10.
Updates #19397
Change-Id: I021c314db2b9d0a80d0088b120a6ade685459990
Reviewed-on: https://go-review.googlesource.com/48370
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
When Stop is called on a channel, wait until all signals have been
delivered to the channel before returning.
Use atomic operations in sigqueue to communicate more reliably between
the os/signal goroutine and the signal handler.
Fixes#14571
Change-Id: I6c5a9eea1cff85e37a34dffe96f4bb2699e12c6e
Reviewed-on: https://go-review.googlesource.com/46003
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Because of parallel tests, which have stalled executions, the RUN
output of a test can be much earlier than its completion output resulting
in hard-to-read verbose output.
The tests are displayed in the order in which the output shows
that they began, to make it easy to line up with the "RUN" output.
Similarly, the definitions of when tests begin and complete is
determined by when RUN and FAIL/SKIP/PASS are output since the
focus of this code is on enhancing readability.
Fixes#19397
Change-Id: I4d0ca3fd268b620484e7a190117f79a33b3dc461
Reviewed-on: https://go-review.googlesource.com/44352
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Since Stop was introduced, it would revert to the system default for the
signal, rather than to the default Go behavior. Change it to revert to
the default Go behavior.
Change-Id: I345467ece0e49e31b2806d6fce2f1937b17905a6
Reviewed-on: https://go-review.googlesource.com/18229
Reviewed-by: Russ Cox <rsc@golang.org>
Use the current ability to say that we don't do anything with SIGCONT by
default, but programs can catch it using signal.Notify if they want.
Fixes#8953.
Change-Id: I67d40ce36a029cbc58a235cbe957335f4a58e1c5
Reviewed-on: https://go-review.googlesource.com/18185
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
The nohup command doesn't work in tmux on darwin.
Fixes#5135.
Change-Id: I1c21073d8bd54b49dd6b0bad86ef088d6d8e7a5f
Reviewed-on: https://go-review.googlesource.com/13883
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
There is currently no way to ignore signals using the os/signal package.
It is possible to catch a signal and do nothing but this is not the same
as ignoring it. The new function Ignore allows a set of signals to be
ignored. The new function Reset allows the initial handlers for a set of
signals to be restored.
Fixes#5572
Change-Id: I5c0f07956971e3a9ff9b9d9631e6e3a08c20df15
Reviewed-on: https://go-review.googlesource.com/3580
Reviewed-by: Ian Lance Taylor <iant@golang.org>
