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runtime: increase assumed stack size in externalthreadhandler

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On Windows, externalthreadhandler currently sets the assumed stack
size for the profiler thread and the ctrlhandler threads to 8KB. The
actual stack size is determined by the SizeOfStackReserve field in the
binary set by the linker, which is currently at least 64KB (and
typically 128KB).

It turns out the profiler thread is running within a few words of the
8KB-(stack guard) bound set by externalthreadhandler. If it overflows
this bound, morestack crashes unceremoniously with an access
violation, which we then fail to handle, causing the whole process to
exit without explanation.

To avoid this problem and give us some breathing room, increase the
assumed stack size in externalthreadhandler to 32KB (there's some
unknown amount of stack already in use, so it's not safe to increase
this all the way to the reserve size).

We also document the relationships between externalthreadhandler and
SizeOfStackReserve to make this more obvious in the future.

Change-Id: I2f9f9c0892076d78e09827022ff0f2bedd9680a9
Reviewed-on: https://go-review.googlesource.com/18304
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
Reviewed-by: Minux Ma <minux@golang.org>
This commit is contained in:
Austin Clements 2016-01-06 12:17:46 -05:00
parent b50b24837d
commit fdf9b3c994
3 changed files with 13 additions and 7 deletions
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15
src/cmd/link/internal/ld/pe.go
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@ -1217,12 +1217,17 @@ func Asmbpe() {
// larger size, as verified with VMMap. // larger size, as verified with VMMap.
// Go code would be OK with 64k stacks, but we need larger stacks for cgo. // Go code would be OK with 64k stacks, but we need larger stacks for cgo.
// That default stack reserve size affects only the main thread, //
// for other threads we specify stack size in runtime explicitly // The default stack reserve size affects only the main
// thread, ctrlhandler thread, and profileloop thread. For
// these, it must be greater than the stack size assumed by
// externalthreadhandler.
//
// For other threads we specify stack size in runtime explicitly
// (runtime knows whether cgo is enabled or not). // (runtime knows whether cgo is enabled or not).
// If you change stack reserve sizes here, // For these, the reserve must match STACKSIZE in
// change STACKSIZE in runtime/cgo/gcc_windows_{386,amd64}.c and correspondent // runtime/cgo/gcc_windows_{386,amd64}.c and the correspondent
// CreateThread parameter in runtime.newosproc as well. // CreateThread parameter in runtime.newosproc.
if !iscgo { if !iscgo {
oh64.SizeOfStackReserve = 0x00020000 oh64.SizeOfStackReserve = 0x00020000
oh.SizeOfStackReserve = 0x00020000 oh.SizeOfStackReserve = 0x00020000

3
src/runtime/sys_windows_386.s
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@ -206,7 +206,8 @@ TEXT runtime·externalthreadhandler(SB),NOSPLIT,$0
CALL runtime·memclr(SB) // smashes AX,BX,CX CALL runtime·memclr(SB) // smashes AX,BX,CX
LEAL g__size(SP), BX LEAL g__size(SP), BX
MOVL BX, g_m(SP) MOVL BX, g_m(SP)
LEAL -8192(SP), CX
LEAL -32768(SP), CX // must be less than SizeOfStackReserve set by linker
MOVL CX, (g_stack+stack_lo)(SP) MOVL CX, (g_stack+stack_lo)(SP)
ADDL $const__StackGuard, CX ADDL $const__StackGuard, CX
MOVL CX, g_stackguard0(SP) MOVL CX, g_stackguard0(SP)

2
src/runtime/sys_windows_amd64.s
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@ -243,7 +243,7 @@ TEXT runtime·externalthreadhandler(SB),NOSPLIT,$0
LEAQ g__size(SP), BX LEAQ g__size(SP), BX
MOVQ BX, g_m(SP) MOVQ BX, g_m(SP)
LEAQ -8192(SP), CX LEAQ -32768(SP), CX // must be less than SizeOfStackReserve set by linker
MOVQ CX, (g_stack+stack_lo)(SP) MOVQ CX, (g_stack+stack_lo)(SP)
ADDQ $const__StackGuard, CX ADDQ $const__StackGuard, CX
MOVQ CX, g_stackguard0(SP) MOVQ CX, g_stackguard0(SP)