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d03e8b226c
If we get a SIGPROF on a non-Go thread, and the program has not called runtime.SetCgoTraceback so we have no way to collect a stack trace, then record a profile that is just the PC where the signal occurred. That will at least point the user to the right area. Retrieving the PC from the sigctxt in a signal handler on a non-G thread required marking a number of trivial sigctxt methods as nosplit, and, for extra safety, nowritebarrierrec. The test shows that the existing test CgoPprofThread test does not test the stack trace, just the profile signal. Leaving that for later. Change-Id: I8f8f3ff09ac099fc9d9df94b5a9d210ffc20c4ab Reviewed-on: https://go-review.googlesource.com/30252 Run-TryBot: Ian Lance Taylor <iant@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
75 lines
2.3 KiB
Go
75 lines
2.3 KiB
Go
// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// +build darwin dragonfly freebsd linux nacl netbsd openbsd
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package runtime
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import "unsafe"
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func dumpregs(c *sigctxt) {
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print("trap ", hex(c.trap()), "\n")
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print("error ", hex(c.error()), "\n")
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print("oldmask ", hex(c.oldmask()), "\n")
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print("r0 ", hex(c.r0()), "\n")
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print("r1 ", hex(c.r1()), "\n")
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print("r2 ", hex(c.r2()), "\n")
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print("r3 ", hex(c.r3()), "\n")
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print("r4 ", hex(c.r4()), "\n")
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print("r5 ", hex(c.r5()), "\n")
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print("r6 ", hex(c.r6()), "\n")
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print("r7 ", hex(c.r7()), "\n")
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print("r8 ", hex(c.r8()), "\n")
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print("r9 ", hex(c.r9()), "\n")
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print("r10 ", hex(c.r10()), "\n")
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print("fp ", hex(c.fp()), "\n")
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print("ip ", hex(c.ip()), "\n")
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print("sp ", hex(c.sp()), "\n")
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print("lr ", hex(c.lr()), "\n")
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print("pc ", hex(c.pc()), "\n")
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print("cpsr ", hex(c.cpsr()), "\n")
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print("fault ", hex(c.fault()), "\n")
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}
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//go:nosplit
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//go:nowritebarrierrec
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func (c *sigctxt) sigpc() uintptr { return uintptr(c.pc()) }
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func (c *sigctxt) sigsp() uintptr { return uintptr(c.sp()) }
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func (c *sigctxt) siglr() uintptr { return uintptr(c.lr()) }
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// preparePanic sets up the stack to look like a call to sigpanic.
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func (c *sigctxt) preparePanic(sig uint32, gp *g) {
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// We arrange lr, and pc to pretend the panicking
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// function calls sigpanic directly.
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// Always save LR to stack so that panics in leaf
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// functions are correctly handled. This smashes
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// the stack frame but we're not going back there
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// anyway.
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sp := c.sp() - 4
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c.set_sp(sp)
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*(*uint32)(unsafe.Pointer(uintptr(sp))) = c.lr()
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pc := gp.sigpc
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// If we don't recognize the PC as code
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// but we do recognize the link register as code,
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// then assume this was a call to non-code and treat like
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// pc == 0, to make unwinding show the context.
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if pc != 0 && findfunc(pc) == nil && findfunc(uintptr(c.lr())) != nil {
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pc = 0
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}
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// Don't bother saving PC if it's zero, which is
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// probably a call to a nil func: the old link register
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// is more useful in the stack trace.
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if pc != 0 {
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c.set_lr(uint32(pc))
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}
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// In case we are panicking from external C code
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c.set_r10(uint32(uintptr(unsafe.Pointer(gp))))
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c.set_pc(uint32(funcPC(sigpanic)))
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}
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