This adds the function "start line number" to runtime._func and
runtime.inlinedCall objects. The "start line number" is the line number
of the func keyword or TEXT directive for assembly.
Subtracting the start line number from PC line number provides the
relative line offset of a PC from the the start of the function. This
helps with source stability by allowing code above the function to move
without invalidating samples within the function.
Encoding start line rather than relative lines directly is convenient
because the pprof format already contains a start line field.
This CL uses a straightforward encoding of explictly including a start
line field in every _func and inlinedCall. It is possible that we could
compress this further in the future. e.g., functions with a prologue
usually have <line of PC 0> == <start line>. In runtime.test, 95% of
functions have <line of PC 0> == <start line>.
According to bent, this is geomean +0.83% binary size vs master and
-0.31% binary size vs 1.19.
Note that //line directives can change the file and line numbers
arbitrarily. The encoded start line is as adjusted by //line directives.
Since this can change in the middle of a function, `line - start line`
offset calculations may not be meaningful if //line directives are in
use.
For #55022.
Change-Id: Iaabbc6dd4f85ffdda294266ef982ae838cc692f6
Reviewed-on: https://go-review.googlesource.com/c/go/+/429638
Run-TryBot: Michael Pratt <mpratt@google.com>
Auto-Submit: Michael Pratt <mpratt@google.com>
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The traceback code has special "jump stack" logic, to trace back
stack switches through systemstack. If we're at the entry of
systemstack, the stack switch hasn't happened, so don't jump to
user stack.
The jump stack logic is only used if we're on the g0 stack. It can
happen that we're at the entry of a recursive systemstack call on
the g0 stack. In we jump stack here, there will be two problems:
1. There are frames between entering the g0 stack and this
recursive systemstack call. Those frames will be lost.
2. Worse, we switched frame.sp but frame.fp calculation will use
the entry SP delta (0), which will be wrong, which in turn
leads wrong frame.lr and things will go off.
For now, don't jump stack if we're at entry of systemstack (SP
delta is 0).
Using a per-PC SPWRITE marker may be a better fix. If we haven't
written the SP, we haven't switched the stack so we can just
unwind like a normal function.
May fix#55851.
Change-Id: I2b624c8c086b235b34d9c7d3cebd4a37264f00f8
Reviewed-on: https://go-review.googlesource.com/c/go/+/437299
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Switch to the more Go-style name to match inlinedCall.nameOff.
Change-Id: I2115b27af8309e1ead7d61ecc65fe4fc966030f7
Reviewed-on: https://go-review.googlesource.com/c/go/+/428657
Run-TryBot: Michael Pratt <mpratt@google.com>
Auto-Submit: Michael Pratt <mpratt@google.com>
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The meaning of this field is unchanged, this CL simply gives it a more
descriptive name, as func_ makes it sound like a reference to the _func.
Change-Id: I70e54f34bede7636ce4d7b9dd0f7557308f02143
Reviewed-on: https://go-review.googlesource.com/c/go/+/427961
Reviewed-by: Cherry Mui <cherryyz@google.com>
Run-TryBot: Michael Pratt <mpratt@google.com>
Reviewed-by: Austin Clements <austin@google.com>
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CL 424257 modified gentraceback to switch gp when jumping from a
system stack to a user stack to simplify reasoning through the rest of
the function. This has the unintended side-effect of also switching
all references to gp.m. The vast majority of the time, g0.m and curg.m
are the same across a stack switch, making this a no-op, but there's
at least one case where this isn't true: if a profiling signal happens
in execute between setting mp.curg and setting gp.m. In this case,
mp.curg.m is briefly nil, which can cause gentraceback to crash with a
nil pointer dereference. We see this failure (surprisingly
frequently!) in profiling tests in the morestack=mayMoreStackPreempt
testing mode (#48297).
Fix this by making only jumping stacks if doing so will not switch Ms.
This restores the original property that gp.m doesn't change across
the stack jump, and makes gentraceback a little more conservative
about jumping stacks.
Fixes#54885.
Change-Id: Ib1524c41c748eeff35896e0f3abf9a7efbe5969f
Reviewed-on: https://go-review.googlesource.com/c/go/+/428656
Reviewed-by: Michael Pratt <mpratt@google.com>
Run-TryBot: Austin Clements <austin@google.com>
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Auto-Submit: Austin Clements <austin@google.com>
Use an atomic.Uint32 to represent the state of finalizer goroutine.
fingStatus will only be changed to fingWake in non fingWait state,
so it is safe to set fingRunningFinalizer status in runfinq.
name old time/op new time/op delta
Finalizer-8 592µs ± 4% 561µs ± 1% -5.22% (p=0.000 n=10+10)
FinalizerRun-8 694ns ± 6% 675ns ± 7% ~ (p=0.059 n=9+8)
Change-Id: I7e4da30cec98ce99f7d8cf4c97f933a8a2d1cae1
Reviewed-on: https://go-review.googlesource.com/c/go/+/400134
Reviewed-by: Joedian Reid <joedian@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
Reviewed-by: Michael Pratt <mpratt@google.com>
The stkframe struct and its methods are strewn across different source
files. Since they actually have a pretty coherent theme at this point,
migrate it all into a new file, stkframe.go. There are no code changes
in this CL.
For #54466, albeit rather indirectly.
Change-Id: Ibe53fc4b1106d131005e1c9d491be838a8f14211
Reviewed-on: https://go-review.googlesource.com/c/go/+/424516
Reviewed-by: Michael Pratt <mpratt@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
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Run-TryBot: Austin Clements <austin@google.com>
Auto-Submit: Austin Clements <austin@google.com>
Currently, stkframe.arglen and stkframe.argmap are populated by
gentraceback under a particular set of circumstances. But because they
can be constructed from other fields in stkframe, they don't need to
be computed eagerly at all. They're also rather misleading, as they're
only part of computing the actual argument map and most callers should
be using getStackMap, which does the rest of the work.
This CL drops these fields from stkframe. It shifts the functions that
used to compute them, getArgInfoFast and getArgInfo, into
corresponding methods stkframe.argBytes and stkframe.argMapInternal.
argBytes is expected to be used by callers that need to know only the
argument frame size, while argMapInternal is used only by argBytes and
getStackMap.
We also move some of the logic from getStackMap into argMapInternal
because the previous split of responsibilities didn't make much sense.
This lets us return just a bitvector from argMapInternal, rather than
both a bitvector, which carries a size, and an "actually use this
size".
The getArgInfoFast function was inlined before (and inl_test checked
this). We drop that requirement from stkframe.argBytes because the
uses of this have shifted and now it's only called from heap dumping
(which never happens) and conservative stack frame scanning (which
very, very rarely happens).
There will be a few follow-up clean-up CLs.
For #54466. This is a nice clean-up on its own, but it also serves to
remove pointers from the traceback state that would eventually become
troublesome write barriers once we stack-rip gentraceback.
Change-Id: I107f98ed8e7b00185c081de425bbf24af02a4163
Reviewed-on: https://go-review.googlesource.com/c/go/+/424514
Run-TryBot: Austin Clements <austin@google.com>
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Reviewed-by: Cherry Mui <cherryyz@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Currently, when traceback jumps from the system stack to a user stack
(e.g., during profiling tracebacks), it leaves gp pointing at the g0.
This is currently harmless since it's only used during profiling, so
the code paths in gentraceback that care about gp aren't used, but
it's really confusing and would certainly break if _TraceJumpStack
were ever used in a context other than profiling.
Fix this by updating gp to point to the user g when we switch stacks.
For #54466.
Change-Id: I1541e004667a52e37671803ce45c91d8c5308830
Reviewed-on: https://go-review.googlesource.com/c/go/+/424257
Reviewed-by: Michael Pratt <mpratt@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Auto-Submit: Austin Clements <austin@google.com>
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Run-TryBot: Austin Clements <austin@google.com>
The f funcInfo argument is always the same as frame.fn, so we don't
need to pass it. I suspect that was there to make the signatures of
getArgInfoFast and getArgInfo more similar, but it's not necessary.
For #54466.
Change-Id: Idc717f4df09e97cad49d52c5b7edf28090908cba
Reviewed-on: https://go-review.googlesource.com/c/go/+/424255
Run-TryBot: Austin Clements <austin@google.com>
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TryBot-Result: Gopher Robot <gobot@golang.org>
Currently, gentraceback tracks the closure context of the outermost
frame. This used to be important for "unstarted" calls to reflect
function stubs, where "unstarted" calls are either deferred functions
or the entry-point of a goroutine that hasn't run. Because reflect
function stubs have a dynamic argument map, we have to reach into
their closure context to fetch to map, and how to do this differs
depending on whether the function has started. This was discovered in
issue #25897.
However, as part of the register ABI, "go" and "defer" were made much
simpler, and any "go" or "defer" of a function that takes arguments or
returns results gets wrapped in a closure that provides those
arguments (and/or discards the results). Hence, we'll see that closure
instead of a direct call to a reflect stub, and can get its static
argument map without any trouble.
The one case where we may still see an unstarted reflect stub is if
the function takes no arguments and has no results, in which case the
compiler can optimize away the wrapper closure. But in this case we
know the argument map is empty: the compiler can apply this
optimization precisely because the target function has no argument
frame.
As a result, we no longer need to track the closure context during
traceback, so this CL drops all of that mechanism.
We still have to be careful about the unstarted case because we can't
reach into the function's locals frame to pull out its context
(because it has no locals frame). We double-check that in this case
we're at the function entry.
I would prefer to do this with some in-code PCDATA annotations of
where to find the dynamic argument map, but that's a lot of mechanism
to introduce for just this. It might make sense to consider this along
with #53609.
Finally, we beef up the test for this so it more reliably forces the
runtime down this path. It's fundamentally probabilistic, but this
tweak makes it better. Scheduler testing hooks (#54475) would make it
possible to write a reliable test for this.
For #54466, but it's a nice clean-up all on its own.
Change-Id: I16e4f2364ba2ea4b1fec1e27f971b06756e7b09f
Reviewed-on: https://go-review.googlesource.com/c/go/+/424254
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
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If a goroutine is started within a user region, internal/trace assigns
the child goroutine a nameless region for its entire lifetime which is
assosciated the same task as the parent's region.
This is not strictly necessary: a child goroutine is not necessarily
related to the task unless it performs some task operation (in which
case it will be associated with the task through the standard means).
However, it can be quite handy to see child goroutines within a region,
which may be child worker goroutines that you simply didn't perform task
operations on.
If the first GC occurs during a region, the GC worker goroutines will
also inherit a child region. We know for sure that these aren't related
to the task, so filter them out from the region list.
Note that we can't exclude system goroutines from setting activeRegions
in EvGoCreate handling, because we don't know the goroutine start
function name until the first EvGoStart.
Fixes#53784.
Change-Id: Ic83d84e23858a8400a76d1ae2f1418ef49951178
Reviewed-on: https://go-review.googlesource.com/c/go/+/416858
Run-TryBot: Michael Pratt <mpratt@google.com>
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Reviewed-by: Michael Knyszek <mknyszek@google.com>
On LR machine, consider F calling G calling H, which grows stack.
The stack looks like
...
G's frame:
... locals ...
saved LR = return PC in F <- SP points here at morestack
H's frame (to be created)
At morestack, we save
gp.sched.pc = H's morestack call
gp.sched.sp = H's entry SP (the arrow above)
gp.sched.lr = return PC in G
Currently, when unwinding through morestack (if _TraceJumpStack
is set), we switch PC and SP but not LR. We then have
frame.pc = H's morestack call
frame.sp = H's entry SP (the arrow above)
As LR is not set, we load it from stack at *sp, so
frame.lr = return PC in F
As the SP hasn't decremented at the morestack call,
frame.fp = frame.sp = H's entry SP
Unwinding a frame, we have
frame.pc = old frame.lr = return PC in F
frame.sp = old frame.fp = H's entry SP a.k.a. G's SP
The PC and SP don't match. The unwinding will go off if F and G
have different frame sizes.
Fix this by preserving the LR when switching stack.
Also add code to detect infinite loop in unwinding.
TODO: add some test. I can reproduce the infinite loop (or throw
with added check) but the frequency is low.
May fix#52116.
Change-Id: I6e1294f1c6e55f664c962767a1cf6c466a0c0eff
Reviewed-on: https://go-review.googlesource.com/c/go/+/400575
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Reviewed-by: Eric Fang <eric.fang@arm.com>
Reviewed-by: Benny Siegert <bsiegert@gmail.com>
This gives explicit names to the possible states of throwing (-1, 0, 1).
m.throwing is now one of:
throwTypeOff: not throwing, previously == 0
throwTypeUser: user throw, previously == -1
throwTypeRuntime: runtime throw, previously == 1
For runtime throws, we now always include frame metadata and system
goroutines regardless of GOTRACEBACK to aid in debugging the runtime.
For user throws, we no longer include frame metadata or runtime frames,
unless GOTRACEBACK=system or higher.
For #51485.
Change-Id: If252e2377a0b6385ce7756b937929be4273a56c0
Reviewed-on: https://go-review.googlesource.com/c/go/+/390421
Run-TryBot: Michael Pratt <mpratt@google.com>
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Reviewed-by: Austin Clements <austin@google.com>
This CL adds support for debugger function calls on linux arm64
platform. The protocol is basically the same as in CL 109699, except for
the following differences:
1, The abi difference which affect parameter passing and frame layout.
2, Stores communication information in R20.
3, The closure register is R26.
4, Use BRK 0 instruction to generate a breakpoint. The saved PC in
sigcontext is the PC where the signal occurred, not the next PC.
In addition, this CL refactors the existing code (which is dedicated to
amd64) for easier multi-arch scaling.
Fixes#50614
Change-Id: I06b14e345cc89aab175f4a5f2287b765da85a86b
Reviewed-on: https://go-review.googlesource.com/c/go/+/395754
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Run-TryBot: Eric Fang <eric.fang@arm.com>
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This makes it easier to figure out where the crash is occurring.
Change-Id: Ie1f78a360367090dcd61c61b2a55c34f3e2ff2eb
Reviewed-on: https://go-review.googlesource.com/c/go/+/390034
Trust: David Chase <drchase@google.com>
Reviewed-by: David Chase <drchase@google.com>
Trust: Michael Pratt <mpratt@google.com>
Run-TryBot: Michael Pratt <mpratt@google.com>
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Reviewed-by: Cherry Mui <cherryyz@google.com>
Like the VDSO, we cannot directly traceback from the Linux kernel ARM
atomic/barrier helpers. However, unlike the VDSO, this functions are
extremely simple. Neither of the functions we use, kuser_cmpxchg and
kuser_memory_barrier, touch SP or LR.
We can use this to our advantage to read LR and simply start tracebacks
in the caller.
Fixes#49182
Change-Id: I890edbeb7c128938000fe7baf6f913c02a956edd
Reviewed-on: https://go-review.googlesource.com/c/go/+/362977
Trust: Michael Pratt <mpratt@google.com>
Run-TryBot: Michael Pratt <mpratt@google.com>
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Add explicit address sanitizer instrumentation to the runtime and
syscall packages. The compiler does not instrument the runtime
package. It does instrument the syscall package, but we need to add
a couple of cases that it can't see.
Refer to the implementation of the asan malloc runtime library,
this patch also allocates extra memory as the redzone, around the
returned memory region, and marks the redzone as unaddressable to
detect the overflows or underflows.
Updates #44853.
Change-Id: I2753d1cc1296935a66bf521e31ce91e35fcdf798
Reviewed-on: https://go-review.googlesource.com/c/go/+/298614
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Trust: fannie zhang <Fannie.Zhang@arm.com>
Currently, for stack traces (e.g. at panic or when runtime.Stack
is called), we print argument values from the stack. With register
ABI, we may never store the argument to stack therefore the
argument value on stack may be meaningless. This causes confusion.
This CL makes the compiler keep trace of which argument stack
slots are meaningful. If it is meaningful, it will be printed in
stack traces as before. If it may not be meaningful, it will be
printed as the stack value with a question mark ("?"). In general,
the value could be meaningful on some code paths but not others
depending on the execution, and the compiler couldn't know
statically, so we still print the stack value, instead of not
printing it at all. Also note that if the argument variable is
updated in the function body the printed value may be stale (like
before register ABI) but still considered meaningful.
Arguments passed on stack are always meaningful therefore always
printed without a question mark. Results are never printed, as
before.
(Due to a bug in the compiler we sometimes don't spill args into
their dedicated spill slots (as we should), causing it having
fewer meaningful values than it should be.)
This increases binary sizes a bit:
old new
hello 1129760 1142080 +1.09%
cmd/go 13932320 14088016 +1.12%
cmd/link 6267696 6329168 +0.98%
Fixes#45728.
Change-Id: I308a0402e5c5ab94ca0953f8bd85a56acd28f58c
Reviewed-on: https://go-review.googlesource.com/c/go/+/352057
Trust: Cherry Mui <cherryyz@google.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
If we receive an async signal while running in the VDSO, such as a
SIGABRT or SIGSEGV sent from another process, we fail to print the
stacktrace with "runtime: unknown pc <vdso PC>".
We already have machinery to handle SIGPROF in the VDSO, but it isn't
hooked up for other signals. Add it to the general signal traceback
path.
This case is covered by TestSegv by making the test more strict w.r.t.
accepted output.
Fixes#47537
Change-Id: I755585f70e0c23e207e135bc6bd2aa68298e5d24
Reviewed-on: https://go-review.googlesource.com/c/go/+/339990
Trust: Michael Pratt <mpratt@google.com>
Run-TryBot: Michael Pratt <mpratt@google.com>
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Reviewed-by: Cherry Mui <cherryyz@google.com>
A subsequent change will alter the semantics of _func.entry.
To make that change obvious and clear, change _func.entry to a method,
and rename the field to _func.entryPC.
Change-Id: I05d66b54d06c5956d4537b0729ddf4290c3e2635
Reviewed-on: https://go-review.googlesource.com/c/go/+/351460
Trust: Josh Bleecher Snyder <josharian@gmail.com>
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
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Two non-conflict changes included because they're needed for all.bash:
1. Bump internal/goversion.Version to 18. This will happen eventually
anyway (dev.typeparams will not be merged back to Go 1.17), and is
needed for cmd/api to allow new API additions.
2. Add fixedbugs/issue46725.go (new test added on master) to the list
of known failures for -G=3. This test exercises a bug that was fixed
in typecheck, but -G=3 mode has duplicated that code and will need to
be fixed as well. That's outside of the scope of a merge.
Conflicts:
- src/runtime/traceback.go
Nearby lines were removed on both master and dev.typeparams.
Merge List:
+ 2021-06-14 fdab5be159 doc/go1.17: further revise OpenBSD release notes
+ 2021-06-14 326ea438bb cmd/compile: rewrite a, b = f() to use temporaries when type not identical
+ 2021-06-14 3249b645c9 cmd/compile: factor out rewrite multi-valued f()
+ 2021-06-13 14305bf0b9 misc/cgo: generate Windows import libraries for clang
+ 2021-06-13 24cff0f044 cmd/go, misc/cgo: skip test if no .edata
+ 2021-06-13 67b1b6a2e3 cmd/compile: allow ir.OSLICE2ARRPTR in mayCall
+ 2021-06-12 1ed0d129e9 runtime: testprogcgo: don't call exported Go functions directly from Go
+ 2021-06-12 9d46ee5ac4 reflect: handle stack-to-register translation in callMethod
+ 2021-06-11 e552a6d312 cmd/go: remove hint when no module is suggested
+ 2021-06-11 16b5d766d8 syscall: do not load native libraries on non-native powershell on arm
+ 2021-06-11 77aa209b38 runtime: loop on EINTR in macOS sigNoteSleep
+ 2021-06-11 e2dc6dd5c9 doc/go1.17: clean up formatting of gofmt section
+ 2021-06-11 2f1128461d cmd/go: match Windows paths in TestScript/mod_invalid_version
+ 2021-06-11 2721da2608 doc/go1.17: fix formatting near httptest
+ 2021-06-10 770f1de8c5 net/http: remove test-only private key from production binaries
+ 2021-06-10 8d11b1d117 cmd/go: report the imports of CompiledGoFiles in ImportMap
+ 2021-06-10 dc00dc6c6b crypto/tls: let HTTP/1.1 clients connect to servers with NextProtos "h2"
+ 2021-06-09 27f83723e9 api: promote next to go1.17
+ 2021-06-09 182157c81a doc/go1.17: remove lingering TODO
+ 2021-06-09 a5bc060b42 doc/go1.17: document strconv changes for Go 1.17
+ 2021-06-09 1402b27d46 strconv: document parsing of leading +/-
+ 2021-06-09 df35ade067 doc/go1.17: document //go:build lines
+ 2021-06-09 e4e7807d24 net/http: add AllowQuerySemicolons
+ 2021-06-09 ec3026d032 doc/go1.17: remove TODO for ports section
+ 2021-06-09 e6dda19888 net/url: reject query values with semicolons
+ 2021-06-09 139e935d3c math/big: comment division
+ 2021-06-09 aa5540cd82 cmd/compile: make map.zero symbol content-addressable
+ 2021-06-09 07ca28d529 cmd/link: fix bug in -strictdups checking of BSS symbols
+ 2021-06-08 bcecae2af6 doc/go1.17: mention new possibility of type conversion panicking
+ 2021-06-08 63dcab2e91 doc/go1.17: mention new vet checks sigchanyzer and stdmethods.
+ 2021-06-08 6551763a60 doc/go1.17: mention block profile bias fix
+ 2021-06-08 cb80937bf6 Revert "doc/go1.17: mention block profile bias fix"
+ 2021-06-08 d3e3d03666 net: reject leading zeros in IP address parsers
+ 2021-06-08 da4a640141 doc/go1.17: revise OpenBSD release notes
+ 2021-06-08 689f4c7415 doc/go1.17: mention block profile bias fix
+ 2021-06-08 9afe071c60 doc/go1.17: remove TODO for Tools section
+ 2021-06-08 f753d7223e doc/go1.17: resolve TODO for cmd/cover
+ 2021-06-08 9498b0155d cmd/go: in Go 1.17+ modules, add indirect go.mod dependencies separately from direct ones
+ 2021-06-08 949f00cebe doc/go1.17: add release notes for crypto packages
+ 2021-06-08 0fb3e2c184 doc/go1.17: add a release note for the '-compat' flag to 'go mod tidy'
+ 2021-06-08 2169deb352 cmd/compile: use t.AllMethods when sorting typesByString
+ 2021-06-08 c20bcb6488 runtime: remove out-of-date comments about frame skipping
+ 2021-06-07 39c39ae52f doc: document Go 1.17 language changes
+ 2021-06-07 dc8b558951 cmd/dist: pass -Wno-lto-type-mismatch in swig_callback_lto
+ 2021-06-07 909dd5e010 strconv: ParseFloat: always return ErrSyntax for bad syntax
Change-Id: Iffdf379d0275bbd12d50149ce38634773ced481d
tracebackdefers is used for scanning/copying deferred functions'
arguments. Now that deferred functions are always argumentless,
it does nothing. Remove.
Change-Id: I55bedabe5584ea41a12cdb03d55ec9692a5aacd9
Reviewed-on: https://go-review.googlesource.com/c/go/+/325916
Trust: Cherry Mui <cherryyz@google.com>
Run-TryBot: Cherry Mui <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Now that defer/go wrapping is used, deferred/go'd functions are
always argumentless. Remove the code handling arguments.
This CL is mostly removing the fallback code path. There are more
cleanups to be done, in later CLs.
Change-Id: I87bfd3fb2d759fbeb6487b8125c0f6992863d6e5
Reviewed-on: https://go-review.googlesource.com/c/go/+/325915
Trust: Cherry Mui <cherryyz@google.com>
Run-TryBot: Cherry Mui <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
skipPleaseUseCallersFrames was removed in CL 152537.
Change-Id: Ide47feec85a33a6fb6882e16baf9e21492521640
Reviewed-on: https://go-review.googlesource.com/c/go/+/325949
Trust: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
It is valid to see SPWRITE functions at the top of a GC stack traceback,
in the case where they self-preempted during the stack growth check
and haven't actually modified SP in a traceback-unfriendly manner yet.
The current check is therefore too aggressive.
isAsyncSafePoint is taking care of not async-preempting SPWRITE functions
because it doesn't async-preempt any assembly functions at all.
But perhaps it will in the future.
To keep a check that SPWRITE assembly functions are not async-preempted,
add one in preemptPark. Then relax the check in traceback to avoid
triggering on self-preempted SPWRITE functions.
The long and short of this is that the assembly we corrected in x/crypto
issue #44269 was incredibly dodgy but not technically incompatible with
the Go runtime. After this change, the original x/crypto assembly no longer
causes GC traceback crashes during "GOGC=1 go test -count=1000".
But we'll still leave the corrected assembly.
This also means that we don't need to worry about diagnosing SPWRITE
assembly functions that may exist in the wild. They will be skipped for
async preemption and no harm no foul.
Fixes#44269, which was open pending some kind of check for
bad SPWRITE functions in the wild. (No longer needed.)
Change-Id: I6000197b62812bbd2cd92da28eab422634cf75a8
Reviewed-on: https://go-review.googlesource.com/c/go/+/317669
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Currently, when the runtime printing a stack track (at panic, or
when runtime.Stack is called), it prints the function arguments
as words in memory. With a register-based calling convention,
the layout of argument area of the memory changes, so the
printing also needs to change. In particular, the memory order
and the syntax order of the arguments may differ. To address
that, this CL lets the compiler to emit some metadata about the
memory layout of the arguments, and the runtime will use this
information to print arguments in syntax order.
Previously we print the memory contents of the results along with
the arguments. The results are likely uninitialized when the
traceback is taken, so that information is rarely useful. Also,
with a register-based calling convention the results may not
have corresponding locations in memory. This CL changes it to not
print results.
Previously the runtime simply prints the memory contents as
pointer-sized words. With a register-based calling convention,
as the layout changes, arguments that were packed in one word
may no longer be in one word. Also, as the spill slots are not
always initialized, it is possible that some part of a word
contains useful informationwhile the rest contains garbage.
Instead of letting the runtime recreating the ABI0 layout and
print them as words, we now print each component separately.
Aggregate-typed argument/component is surrounded by "{}".
For example, for a function
F(int, [3]byte, byte) int
when called as F(1, [3]byte{2, 3, 4}, 5), it used to print
F(0x1, 0x5040302, 0xXXXXXXXX) // assuming little endian, 0xXXXXXXXX is uninitilized result
Now prints
F(0x1, {0x2, 0x3, 0x4}, 0x5).
Note: the liveness tracking of the spill splots has not been
implemented in this CL. Currently the runtime just assumes all
the slots are live and print them all.
Increase binary sizes by ~1.5%.
old new
hello (println) 1171328 1187712 (+1.4%)
hello (fmt) 1877024 1901600 (+1.3%)
cmd/compile 22326928 22662800 (+1.5%)
cmd/go 13505024 13726208 (+1.6%)
Updates #40724.
Change-Id: I351e0bf497f99bdbb3f91df2fb17e3c2c5c316dc
Reviewed-on: https://go-review.googlesource.com/c/go/+/304470
Trust: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
This change finishes off functionality register ABI for the reflect
package.
Specifically, it implements a call on a MakeFunc'd value by performing
the reverse process that reflect.Value.Call does, using the same ABI
steps. It implements a call on a method value created by reflect by
translating between the method value's ABI to the method's ABI.
Tests are added for both cases.
For #40724.
Change-Id: I302820b61fc0a8f94c5525a002bc02776aef41af
Reviewed-on: https://go-review.googlesource.com/c/go/+/298670
Trust: Michael Knyszek <mknyszek@google.com>
Run-TryBot: Michael Knyszek <mknyszek@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Correctly accessing allgs is a bit hairy. Some paths need to lock
allglock, some don't. Those that don't are safest using atomicAllG, but
usage is not consistent.
Rather than doing this ad-hoc, move all access* through forEachG /
forEachGRace, the locking and atomic versions, respectively. This will
make it easier to ensure safe access.
* markroot is the only exception, as it has a far-removed guarantee of
safe access via an atomic load of allglen far before actual use.
Change-Id: Ie1c7a8243e155ae2b4bc3143577380c695680e89
Reviewed-on: https://go-review.googlesource.com/c/go/+/279994
Trust: Michael Pratt <mpratt@google.com>
Run-TryBot: Michael Pratt <mpratt@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
netbsd/amd64's Syscall9 changes SP using ADD and SUB,
which are treated as SPWRITEs (they are not accounted for
in the sp-adjust tracking, and there are too many functions that
would report mismatched stack adjustments at RET if they were).
A traceback starting in Syscall9 as saved by entersyscall complains
about the SPWRITE-ness unnecessarily, since the PC/SP are saved
at the start of the function. Ignore SPWRITE in that case.
netbsd/arm's Syscall6 also changes SP (R13), using a direct write.
So even if we could handle the ADD/SUB in the amd64 case or
rewrote that assembly, we'd still be stuck with a more difficult
problem in this case. Ignoring the SPWRITE fixes it.
Example crashes:
https://build.golang.org/log/160fc7b051a2cf90782b75a99984fff129329e66https://build.golang.org/log/7879e2fecdb400eee616294285e1f952e5b17301
Change-Id: I0c8e9696066e90dafed6d4a93d11697da23f0080
Reviewed-on: https://go-review.googlesource.com/c/go/+/294072
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
Frame pointers were already enabled on linux, darwin, ios,
but not freebsd, android, openbsd, netbsd.
But the space was reserved on all platforms, leading to
two different arm64 framepointer conditions in different
parts of the code, one of which had no name
(framepointer_enabled || GOARCH == "arm64",
which might have been "framepointer_space_reserved").
So on the disabled systems, the stack layouts were still
set up for frame pointers and the only difference was not
actually maintaining the FP register in the generated code.
Reduce complexity by just enabling the frame pointer
completely on all the arm64 systems.
This commit passes on freebsd, android, netbsd.
I have not been able to try it on openbsd.
This CL is part of a stack adding windows/arm64
support (#36439), intended to land in the Go 1.17 cycle.
This CL is, however, not windows/arm64-specific.
It is cleanup meant to make the port (and future ports) easier.
Change-Id: I83bd23369d24b76db4c6a648fa74f6917819a093
Reviewed-on: https://go-review.googlesource.com/c/go/+/288814
Trust: Russ Cox <rsc@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
This was added in 2018 to fix a runtime crash during unwind
during a unhandled-panic-induced crash.
(See https://golang.org/cl/90895 and #23576.)
Clearly we cannot unwind past this function, and the change
did stop the unwind. But it's not a top-of-stack function, and
the real issue is that SP is changed.
The new SPWRITE bit takes care of this instead, so we can drop
it from the topofstack function.
At this point the topofstack function is only checking the
TOPFRAME bit, so we can inline that into the one call site.
This CL is part of a stack adding windows/arm64
support (#36439), intended to land in the Go 1.17 cycle.
This CL is, however, not windows/arm64-specific.
It is cleanup meant to make the port (and future ports) easier.
Change-Id: I856552298032770e48e06c95a20823a1dbd5e38c
Reviewed-on: https://go-review.googlesource.com/c/go/+/288805
Trust: Russ Cox <rsc@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
I added morestack to this list in 2013 with an explanation
that they were needed if we “start a garbage collection on g0
during a stack split or unsplit”.
(https://golang.org/cl/11533043)
This explanation no longer applies for a handful of reasons,
most importantly that if we did stop a stack scan in the middle
of a call to morestack, we'd ignore pointers above the split,
which would lead to memory corruption. But we don't scan
goroutine stacks during morestack now, so that can't happen.
If we did see morestack during a GC, that would be a good time
to crash the program.
The real problem with morestack is during profiling, as noted
in the code review conversation during 2013. And in profiling
we just need to know to stop and not unwind further, which
the new SPWRITE bit will do for us.
So remove from topofstack and let the program crash if GC
sees morestack and otherwise let the SPWRITE stop morestack
unwinding during profiling.
This CL is part of a stack adding windows/arm64
support (#36439), intended to land in the Go 1.17 cycle.
This CL is, however, not windows/arm64-specific.
It is cleanup meant to make the port (and future ports) easier.
Change-Id: I06d95920b18c599c7c46f64c21028104978215d7
Reviewed-on: https://go-review.googlesource.com/c/go/+/288804
Trust: Russ Cox <rsc@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
I added mcall to this list in 2013 without explaining why.
(https://codereview.appspot.com/11085043/diff/61001/src/pkg/runtime/traceback_x86.c)
I suspect I was stopping crashes during profiling where the unwind
tried to walk up past mcall and got confused.
mcall is not something you can unwind past, because it switches
stacks, but it's also not something you should expect as a
standard top-of-stack frame. So if you do see it during say
a garbage collection stack walk, it would be important to crash
instead of silently stopping the walk prematurely.
This CL removes it from the topofstack list to avoid the silent stop.
Now that mcall is detected as SPWRITE, that will stop the
unwind (with a crash if encountered during GC, which we want).
This CL is part of a stack adding windows/arm64
support (#36439), intended to land in the Go 1.17 cycle.
This CL is, however, not windows/arm64-specific.
It is cleanup meant to make the port (and future ports) easier.
Change-Id: I666487ce24efd72292f2bc3eac7fe0477e16bddd
Reviewed-on: https://go-review.googlesource.com/c/go/+/288803
Trust: Russ Cox <rsc@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
No change to actual runtime, but helps reduce the laundry list
of functions.
mcall, morestack, and asmcgocall are not actually top-of-frame,
so those need more attention in follow-up CLs.
mstart moved to assembly so that it can be marked TOPFRAME.
Since TOPFRAME also tells DWARF consumers not to unwind
this way, this change should also improve debuggers a
marginal amount.
This CL is part of a stack adding windows/arm64
support (#36439), intended to land in the Go 1.17 cycle.
This CL is, however, not windows/arm64-specific.
It is cleanup meant to make the port (and future ports) easier.
Change-Id: If1e0d46ca973de5e46b62948d076f675f285b5d9
Reviewed-on: https://go-review.googlesource.com/c/go/+/288802
Trust: Russ Cox <rsc@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
The old code was very clever about predicting whether a traceback was safe.
That cleverness has not aged well. In particular, the setsSP function is missing
a bunch of functions that write to SP and will confuse traceback.
And one such function - jmpdefer - was handled as a special case in
gentraceback instead of simply listing it in setsSP.
Throw away all the clever prediction about whether traceback will crash.
Instead, make traceback NOT crash, by checking whether the function
being walked writes to SP.
This CL is part of a stack adding windows/arm64
support (#36439), intended to land in the Go 1.17 cycle.
This CL is, however, not windows/arm64-specific.
It is cleanup meant to make the port (and future ports) easier.
Change-Id: I3d55fe257a22745e4919ac4dc9a9378c984ba0da
Reviewed-on: https://go-review.googlesource.com/c/go/+/288801
Trust: Russ Cox <rsc@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Document what the values in internal/sys mean.
Remove various special cases for arm64 in the code using StackAlign.
Delete Uintreg - it was for GOARCH=amd64p32,
which was specific to GOOS=nacl and has been retired.
This CL is part of a stack adding windows/arm64
support (#36439), intended to land in the Go 1.17 cycle.
This CL is, however, not windows/arm64-specific.
It is cleanup meant to make the port (and future ports) easier.
Change-Id: I40e8fa07b4e192298b6536b98a72a751951a4383
Reviewed-on: https://go-review.googlesource.com/c/go/+/288795
Trust: Russ Cox <rsc@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
tracebackothers is called from fatal throw/panic.
A fatal throw may be taken with allglock held (notably in the allocator
when allglock is held), which would cause a deadlock in tracebackothers
when we try to take allglock again. Locking allglock here is also often
a lock order violation w.r.t. the locks held when throw was called.
Avoid the deadlock and ordering issues by skipping locking altogether.
It is OK to miss concurrently created Gs (which are generally avoided by
freezetheworld(), and which were possible previously anyways if created
after the loop).
Fatal throw/panic freezetheworld(), which should freeze other threads
that may be racing to modify allgs. However, freezetheworld() does _not_
guarantee that it stops all other threads, so we can't simply drop the
lock.
Fixes#42669
Updates #43175
Change-Id: I657aec46ed35fd5d1b3f1ba25b500128ab26b088
Reviewed-on: https://go-review.googlesource.com/c/go/+/270861
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Trust: Michael Pratt <mpratt@google.com>
Currently, gentraceback decides which frames to print or elide when
unwinding inlined frames using only the name of the outermost
function. If the outermost function should be elided, then inlined
functions will also be elided, even if they shouldn't be.
This happens in practice in at least one situation. As of CL 258938,
exported Go functions (and functions they call) can now be inlined
into the generated _cgoexp_HASH_FN function. The runtime elides
_cgoexp_HASH_FN from tracebacks because it doesn't contain a ".".
Because of this bug, it also elides anything that was inlined into it.
This CL fixes this by synthesizing a funcInfo for the inlined
functions to pass to showframe.
Fixes#42754.
Change-Id: Ie6c663a4a1ac7f0d4beb1aa60bc26fc8cddd0f9d
Reviewed-on: https://go-review.googlesource.com/c/go/+/272131
Trust: Austin Clements <austin@google.com>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
This reverts commit 3a81338622.
Reason for revert: Some edge cases not properly covered due to changes within runtime traceback generation since 2017, that need to be examined. This change landed very late in the Go1.16 cycle.
Change-Id: I8cf6f46ea0ef6161d878e79943e6c7cdac94bccf
Reviewed-on: https://go-review.googlesource.com/c/go/+/268577
Trust: Emmanuel Odeke <emmanuel@orijtech.com>
Run-TryBot: Emmanuel Odeke <emmanuel@orijtech.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
cui fliter
Michael Pratt
Cherry Mui
Austin Clements
Leonard Wang
Cuong Manh Le
eric fang
fanzha02
Josh Bleecher Snyder
Yasuhiro Matsumoto
Michael Anthony Knyszek
Matthew Dempsky
Russ Cox
Emmanuel Odeke