Add SymbolBuilder helper type -- this type provides a set of methods
intended to make it easy to manipulate the content of a symbol (type,
relocations, data, etc).
Change-Id: I579bf8d04650e66d33a9780a6c2347a576c94c6f
Reviewed-on: https://go-review.googlesource.com/c/go/+/210178
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Add a loader method to retrieve the version from a loader.Sym
(useful mainly for debugging at the moment).
Change-Id: I82e0e316bb86eb41b9cf366e656a0f848cf3424e
Reviewed-on: https://go-review.googlesource.com/c/go/+/212617
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
This patch fixes a couple of bugs introduced in CL 210778 and CL 207606:
- apply the same version selection scheme in loader.CreateExtSym that
we're currently using for loader.Create (since the two functions
will be used in the same way by the host object loader)
- add code to the loader's NewLoader function to create initial map
values for some of the map-based symbol attributes (somewhere along
the line the code to do this seems to have gotten lost, so this
patch adds it back).
- fix a coding error in growAttrBitmaps (wrong bitmap passed to
append when extending attrOnList)
Change-Id: Ie0c8c6876428bb21d788c19a7a2db945ac649fac
Reviewed-on: https://go-review.googlesource.com/c/go/+/212097
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Add new methods to get/set the "dynimplib", "dynimpvers" and
"localentry" attributes for an external Sym in loader.Loader. These
attribute values are stored sparsely, since we expect that most
symbols will not need them; they are set when processing cgo
directives and when dealing with host object symbols.
Change-Id: If0b3c173307801d39cb576bb99c83b9081c42d9c
Reviewed-on: https://go-review.googlesource.com/c/go/+/211298
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Add a mechanism for recording symbol alignment for external symbols
under the new loader scheme. Alignments is stored in a side table,
since most symbols don't wind up needing an alignment other than zero.
Change-Id: I97092481412c15eac9b9f4c29b5c273f53759562
Reviewed-on: https://go-review.googlesource.com/c/go/+/210177
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Add a new loader method SymSortSub that sorts the sub-symbols
of a given outer symbol (designed to be compatible with the
existing sym.Symbol method).
Change-Id: Icd6627b2e6d04524d657e712cfd39fda0e0e080b
Reviewed-on: https://go-review.googlesource.com/c/go/+/211297
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Add a loader mechanism for recording outer/sub relationships between
symbols without falling back on sym.Symbol. Also includes a new
"PrependSub" method that provides a way to chain a sub-symbol only the
list of an outer symbol (a common operation when manipulating
outer/sub relationships in the linker).
Change-Id: I70c72356945ceec2bacdcdc25bcc352bfb6765a1
Reviewed-on: https://go-review.googlesource.com/c/go/+/210777
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Add loader methods SymValue() and SetSymValue() to get/set the
value of a symbol by global index.
Change-Id: Ifc71480fc34c719ad00506d0828edf36c1a57119
Reviewed-on: https://go-review.googlesource.com/c/go/+/211302
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Add in a collection of new loader interfaces for getting/setting
symbol attributes, e.g. properties that would normally be part of the
sym.Symbol "Attr" field. This change also moves references to the
loaders 'reachable' bitmap behind a pair of loader methods, so that we
a consistent way of accessing symbol attributes overall. It is worth
noting that not every symbol attribute is backed by a bitmap; for some
infrequently used attributes, a map[Sym]struct{} is used instead.
Change-Id: I0010c9cd928d41b4bb6cdf45db4581e11c3c5db3
Reviewed-on: https://go-review.googlesource.com/c/go/+/210778
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Create loader infrastructure for constructing the payloads of external
symbols from scratch, as opposed to passing in a sym.Symbol object
containing the payload.
The general idea is that clients can use the loader to create new
external Sym's using loader.AddExtSym, and then can add
relocations/data to the new sym with symbol builder interfaces (to be
provided in an subsequent patch), as opposed to having to use
sym.Symbol.
This change preserves compatibility with the old way of doing things
(passing in sym.Symbol) via a new loader.InstallSym method. If a
client invokes this method for a specific Sym, then the loader keeps
track of this fact and uses the sym.Symbol as the backing store instead.
Also included is a small unit test for the new interfaces -- not clear
whether this really needs to be kept around long term... it was mainly
useful during initial bringup.
Change-Id: If8ab15df7b64636e56b317155dfe6d7cdfe23b71
Reviewed-on: https://go-review.googlesource.com/c/go/+/207606
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Pushing the wavefront forward requires a single source of truth for
symbols. This CL removes sym.Symbols from the loader for host object
loaders, allowing us to have the single source of truth for symbols be
the loader, not some strange combination of sym.Symbols and the loader.
Change-Id: Ib8ff0117ebe6040fade346047535ff342d781081
Reviewed-on: https://go-review.googlesource.com/c/go/+/209217
Run-TryBot: Jeremy Faller <jeremy@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
In the linker's symtab() function, avoid looping over the context's
Syms.Allsyms array to locate the entry symbol when setting up the init
array section; do an explicit ABI0 symbol lookup instead. This is a
minor efficiency tweak / code cleanup.
Fixes#20205.
Change-Id: I2ebc17a3cb2cd63e9f5052bc80f1b0ac72c960e3
Reviewed-on: https://go-review.googlesource.com/c/go/+/209838
Run-TryBot: Than McIntosh <thanm@google.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Bring in Than's fix of #35779.
The only merge conflict is cmd/link/internal/loadelf/ldelf.go,
with a modification-deletion conflict.
Change-Id: Id2fcfd2094a31120966a6ea9c462b4ec76646b10
Additional vet flags specified by user are discarded if 'go vet'
is invoked outside $GOROOT/src to check a package under $GOROOT
(including those under "vendor" of $GOROOT), fix it by avoiding the
overwriting, the logic of detemining if the package under vetting
comes from $GOROOT remains untouched.
Also checked 'go tool vet <options> <cfg>' and 'go vet <options>
<user pkg>', both worked w./w.o this fix.
Fixes#35837.
Change-Id: I549af7964e40440afd35f2d1971f77eee6f8de34
Reviewed-on: https://go-review.googlesource.com/c/go/+/209498
Run-TryBot: Jay Conrod <jayconrod@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Jay Conrod <jayconrod@google.com>
We were using the race context of the P that held the timer,
but since we unlock the P's timers while executing a timer
that could lead to a race on the race context itself.
Updates #6239
Updates #27707Fixes#35906
Change-Id: I5f9d5f52d8e28dffb88c3327301071b16ed1a913
Reviewed-on: https://go-review.googlesource.com/c/go/+/209580
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
The previous fix for this issue (CL 208479) was not general enough;
this patch revises it to handle more cases.
The problem with the original fix was that once a sym.Symbol is
created for a given static symbol and given a bogus anonymous version
of -1, we hit problems if some other non-anonymous symbol (created by
host object loading) had relocations targeting the static symbol.
In this patch instead of assigning a fixed anonymous version of -1 to
such symbols, each time loader.Create is invoked we create a new
(unique) anonymous version for the sym.Symbol, then enter the result
into the loader's extStaticSyms map, permitting it to be found in
lookups when processing relocation targets.
NB: this code will hopefully get a lot simpler once we can move host
object loading away from early sym.Symbol creation.
Updates #35779.
Change-Id: I450ff577e17549025565d355d6707a2d28a5a617
Reviewed-on: https://go-review.googlesource.com/c/go/+/208778
Run-TryBot: Than McIntosh <thanm@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
The commit de36d1 (CL 4635083) changed the test time
from 2009 to 2010 but forgot to update the comment.
Change-Id: Ia2928773dd184f168fddde126d0bb936de8cfc29
GitHub-Last-Rev: bf8eb57140
GitHub-Pull-Request: golang/go#35930
Reviewed-on: https://go-review.googlesource.com/c/go/+/209517
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Plan 9 doesn't have a way to reserve virtual memory, so the
implementation of sysReserve allocates memory space (which won't
be backed with real pages until the virtual pages are referenced).
If the space is then freed with sysFree, it's not returned to
the OS (because Plan 9 doesn't allow shrinking a shared address
space), but it must be cleared to zeroes in case it's reallocated
subsequently.
This interacts badly with the way mallocinit on 64-bit machines
sets up the heap, calling sysReserve repeatedly for a very large
(64MB?) arena with a non-nil address hint, and then freeing the space
again because it doesn't have the expected alignment. The
repeated clearing of multiple megabytes adds significant startup
time to every go program.
We correct this by restricting sysReserve to allocate memory only
when the caller doesn't provide an address hint. If a hint is
provided, sysReserve will now return nil instead of allocating memory
at a different address.
Fixes#27744
Change-Id: Iae5a950adefe4274c4bc64dd9c740d19afe4ed1c
Reviewed-on: https://go-review.googlesource.com/c/go/+/207917
Run-TryBot: David du Colombier <0intro@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David du Colombier <0intro@gmail.com>
This change makes it so that waking up the scavenger readies its
goroutine without "next" set, so that it doesn't interfere with the
application's use of the runnext feature in the scheduler which helps
fairness.
As of CL 201763 the scavenger began waking up much more often, and in
TestPingPongHog this meant that it would sometimes supercede either a
hog or light goroutine in runnext, leading to a skew in the results and
ultimately a test flake.
This change thus re-enables the TestPingPongHog test on the builders.
Fixes#35271.
Change-Id: Iace08576912e8940554dd7de6447e458ad0d201d
Reviewed-on: https://go-review.googlesource.com/c/go/+/208380
Run-TryBot: Michael Knyszek <mknyszek@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Adds an additional lock around an access to modOnly.
Updates #35317
Change-Id: Ia1e75f9a674ec2a2c0489b41283c1cd3e7924d1e
Reviewed-on: https://go-review.googlesource.com/c/go/+/209237
Run-TryBot: Jay Conrod <jayconrod@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Jay Conrod <jayconrod@google.com>
Lack of logging hinders debugging. Like many other go commands,
let's allow users to inspect what is going on underneath.
Example:
$ GO111MODULE=on GOPROXY=direct GOPATH=`mktemp -d` go mod download -x golang.org/x/tools/gopls@latest
mkdir -p /var/folders/bw/6r6k9d113sv1_vvzk_1kfxbm001py5/T/tmp.ykhTiXaS/pkg/mod/cache/vcs # git3 https://go.googlesource.com/tools
...
Update #35849
Change-Id: I5577e683ae3c0145b11822df255b210ad9f60c87
Reviewed-on: https://go-review.googlesource.com/c/go/+/208558
Run-TryBot: Hyang-Ah Hana Kim <hyangah@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
Currently scavengeAll (which is called by debug.FreeOSMemory) doesn't
reset the scavenge address before scavenging, meaning it could miss
large portions of the heap. Fix this by reseting the address before
scavenging, which will ensure it is able to walk over the entire heap.
Fixes#35858.
Change-Id: I4a7408050b8e134318ff94428f98cb96a1795aa9
Reviewed-on: https://go-review.googlesource.com/c/go/+/208960
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Note that ioutil.WriteFile's perm argument is the value before the
umask is applied.
Fixes#35835
Change-Id: I61cd9c88bced3be52b616d86e060cd3fd912ab1f
Change-Id: I61cd9c88bced3be52b616d86e060cd3fd912ab1f
GitHub-Last-Rev: 0069abb7c5
GitHub-Pull-Request: golang/go#35836
Reviewed-on: https://go-review.googlesource.com/c/go/+/208838
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Print the current SP and (old) stack bounds when the stack grows
too large. This helps to identify the problem: whether a large
stack is used, or something else goes wrong.
For #35470.
Change-Id: I34a4064d5c7280978391d835e171b90d06f87222
Reviewed-on: https://go-review.googlesource.com/c/go/+/207351
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
When there are both a synchronous preemption request (by
clobbering the stack guard) and an asynchronous one (by signal),
the running goroutine may observe the synchronous request first
in stack bounds check, and go to the path of calling morestack.
If the preemption signal arrives at this point before the call to
morestack, the goroutine will be asynchronously preempted,
entering the scheduler. When it is resumed, the scheduler clears
the preemption request, unclobbers the stack guard. But the
resumed goroutine will still call morestack, as it is already on
its way. morestack will, as there is no preemption request,
double the stack unnecessarily. If this happens multiple times,
the stack may grow too big, although only a small amount is
actually used.
To fix this, we mark the stack bounds check and the call to
morestack async-nonpreemptible, starting after the memory
instruction (mostly a load, on x86 CMP with memory).
Not done for Wasm as it does not support async preemption.
Fixes#35470.
Change-Id: Ibd7f3d935a3649b80f47539116ec9b9556680cf2
Reviewed-on: https://go-review.googlesource.com/c/go/+/207350
Reviewed-by: David Chase <drchase@google.com>
Currently we use stack map index -2 to mark unsafe points, i.e.
PC ranges that is not safe for async preemption. This has a
problem: it cannot mark CALL instructions, because for stack scan
a valid stack map index is needed.
This CL switches to use register map index for marking unsafe
points instead, which does not conflict with stack scan and can
be applied on CALL instructions. This is necessary as next CL
will mark call to morestack nonpreemptible.
For #35470.
Change-Id: I357bf26c996e1fee1e7eebe4e6bb07d62930d3f7
Reviewed-on: https://go-review.googlesource.com/c/go/+/207349
Reviewed-by: David Chase <drchase@google.com>
Based on 'go help goproxy'.
Updates #33637
Change-Id: I2f3477cfc8f6fb53515604a28a5bc01eb4fe8f48
Reviewed-on: https://go-review.googlesource.com/c/go/+/208777
Reviewed-by: Katie Hockman <katie@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
This CL pulls in a fix to golang.org/x/mod/modfile. No change needed
to cmd/go.
Fixes#35737
Change-Id: I7ca1bb46d2923b01587042f0f312d3c3df54c425
Reviewed-on: https://go-review.googlesource.com/c/go/+/208977
Run-TryBot: Jay Conrod <jayconrod@google.com>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
On darwin, we use libc calls, and cgo is required on ARM and
ARM64 so we have TLS set up to save/restore G during C calls. If
cgo is absent, we cannot save/restore G in TLS, and if a signal
is received during C execution we cannot get the G. Therefore
don't send signals (and hope that we won't receive any signal
during C execution).
This can only happen in the go_bootstrap program (otherwise cgo
is required).
Fixes#35800.
Change-Id: I6c02a9378af02c19d32749a42db45165b578188d
Reviewed-on: https://go-review.googlesource.com/c/go/+/208818
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
rmdir is a built-in of cmd.exe. It's also an alias in powershell.exe. We
want always the cmd.exe on, so specify it explicitly.
Fixes#35813
Change-Id: I89723e993ee26a20b42d03b8a725ff10ccf30505
Reviewed-on: https://go-review.googlesource.com/c/go/+/208639
Run-TryBot: Jason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Instead of installing shared libraries to GOROOT/pkg, clone the
necessary files into a new GOROOT and run there.
Given that we now have a build cache, ideally we should not need to
install into GOROOT/pkg at all, but we can't fix that during the 1.14
code freeze.
Updates #28387
Updates #28553
Updates #30316
Change-Id: I83084a8ca29a5dffcd586c7fccc3f172cac57cc6
Reviewed-on: https://go-review.googlesource.com/c/go/+/208482
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Jay Conrod <jayconrod@google.com>
Otherwise, these tests produce no output, which can make the overall
output of all.bash a bit tricky to decipher.
Updates #30316
Updates #29062
Change-Id: I33b9e070fd28b9f21ece128e9e603a982c08b7cc
Reviewed-on: https://go-review.googlesource.com/c/go/+/208483
Run-TryBot: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Jay Conrod <jayconrod@google.com>
It turns out that the relative-path support never worked in the first
place.
It had been masked by the fact that we ~never invoke overlayDir with
an absolute path, which caused filepath.Rel to always return an error,
and overlayDir to always fall back to absolute paths.
Since the absolute paths seem to be working fine (and are simpler),
let's stick with those. As far as I can recall, the relative paths
were only a space optimization anyway.
Updates #28387
Updates #30316
Change-Id: Ie8cd28f3c41ca6497ace2799f4193d7f5dde7a37
Reviewed-on: https://go-review.googlesource.com/c/go/+/208481
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Jay Conrod <jayconrod@google.com>
This Patch describes NOOP in Go assembly syntax and gives Go assembly
example and corresponding GNU assembly example.
Change-Id: I9db659cc5e3dc6b1f1450f2064255af8872d4b1c
Reviewed-on: https://go-review.googlesource.com/c/go/+/207400
Run-TryBot: eric fang <eric.fang@arm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
cgo_mmap.go:mmap() is called by mem_linux.go:sysAlloc(), a low-level memory
allocation function. mmap() should be nosplit, since it is called in a lot of
low-level parts of the runtime and callers often assume it won't acquire any
locks.
As an example there is a potential deadlock involving two threads if mmap is not nosplit:
trace.bufLock acquired, then stackpool[order].item.mu, then mheap_.lock
- can happen for traceEvents that are not invoked on the system stack and cause
a traceFlush, which causes a sysAlloc, which calls mmap(), which may cause a
stack split. mheap_.lock
mheap_.lock acquired, then trace.bufLock
- can happen when doing a trace in reclaimChunk (which holds the mheap_ lock)
Also, sysAlloc() has a comment that it is nosplit because it may be invoked
without a valid G, in which case its callee mmap() should also be nosplit.
Similarly, sys_darwin.go:mmap() is called by mem_darwin.go:sysAlloc(), and should
be nosplit for the same reasons.
Extra gomote testing: linux/arm64, darwin/amd64
Change-Id: Ia4d10cec5cf1e186a0fe5aab2858c6e0e5b80fdc
Reviewed-on: https://go-review.googlesource.com/c/go/+/207844
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Skip TestMinusRSymsWithSameName testpoint on MIPS for the time being
since it triggers failures on that arch. Will re-enable once the
problems are fixed.
Updates #35779.
Change-Id: I3e6650158ab04a2be77e3db5a5194df3bbb0859e
Reviewed-on: https://go-review.googlesource.com/c/go/+/208557
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Because of concurrent goroutines it is possible for multiple event
handlers to return at the same time. This was not properly supported
and caused the wrong goroutine to continue, which in turn caused
memory corruption.
This change adds a stack of events so it is always clear which is the
innermost event that needs to return next.
Fixes#35256
Change-Id: Ia527da3b91673bc14e84174cdc407f5c9d5a3d09
Reviewed-on: https://go-review.googlesource.com/c/go/+/204662
Run-TryBot: Richard Musiol <neelance@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
This adds a new test that builds a small Go program with linked
against a *.syso file that is the result of an "ld -r" link. The
sysobj in question has multiple static symbols in the same section
with the same name, which triggered a bug in the loader in -newobj
mode.
Updates #35779.
Change-Id: Ibe1a75662dc1d49c4347279e55646ee65a81508e
Reviewed-on: https://go-review.googlesource.com/c/go/+/208478
Reviewed-by: Cherry Zhang <cherryyz@google.com>
When the ELF host object loader encounters a static/hidden symbol, it
creates a sym.Symbol for it but does not enter it into the sym.Symbols
lookup table. Under -newobj mode, this was not happening correctly; we
were adding the sym via loader.LookupOrCreate, which resulted in
collisions when it encountered symbols with the same name + version +
section (this can happen for "ld -r" objects).
Fixes#35779.
Change-Id: I36d40fc1efc03fc1cd8ae6b76cb6a0d2a957389c
Reviewed-on: https://go-review.googlesource.com/c/go/+/208479
Run-TryBot: Than McIntosh <thanm@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Before May 2018, I mistakenly thought the _suffix naming convention¹
used by examples also applied to tests. Thanks to a code review comment²
from Ian Lance Taylor, I have since learned that is not true.
This trivial change fixes some collateral damage from my earlier
misunderstanding, resulting in improved test naming consistency.
¹ https://golang.org/pkg/testing/#hdr-Examples
² https://go-review.googlesource.com/c/go/+/112935/1/src/path/filepath/path_test.go#1075
Change-Id: I555f60719629eb64bf2f096aa3dd5e00851827cd
Reviewed-on: https://go-review.googlesource.com/c/go/+/207446
Run-TryBot: Dmitri Shuralyov <dmitshur@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Both laptops closing their lids and cloud container runtimes
suspending VMs both faced the problem where an idle HTTP connection
used by the Transport could be cached for later reuse before the
machine is frozen, only to wake up many minutes later to think that
their HTTP connection was still good (because only a second or two of
monotonic time passed), only to find out that the peer hung up on them
when they went to write.
HTTP/1 connection reuse is inherently racy like this, but no need for
us to step into a trap if we can avoid it. Also, not everybody sets
Request.GetBody to enable re-tryable POSTs. And we can only safely
retry requests in some cases.
So with this CL, before reusing an old connection, double check the walltime.
Testing was done both with a laptop (closing the lid for a bit) and
with QEMU, running "stop" and "cont" commands in the monitor and
sending QMP guest agent commands to update its wall clock after the
"cont":
echo '{"execute":"guest-set-time"}' | socat STDIN UNIX-CONNECT:/var/run/qemu-server/108.qga
In both cases, I was running
https://gist.github.com/bradfitz/260851776f08e4bc4dacedd82afa7aea and
watching that the RemoteAddr changed after resume.
It's kinda difficult to write an automated test for. I gave a lightning talk on
using pure emulation user mode qemu for such tests:
https://www.youtube.com/watch?v=69Zy77O-BUMhttps://docs.google.com/presentation/d/1rAAyOTCsB8GLbMgI0CAbn69r6EVWL8j3DPl4qc0sSlc/edit?usp=sharinghttps://github.com/google/embiggen-disk/blob/master/integration_test.go
... that would probably be a good direction if we want an automated
test here. But I don't have time to do that now.
Updates #29308 (HTTP/2 remains)
Change-Id: I03997e00491f861629d67a0292da000bd94ed5ca
Reviewed-on: https://go-review.googlesource.com/c/go/+/204797
Reviewed-by: Bryan C. Mills <bcmills@google.com>
