This CL contains compiler+runtime changes that detect C code
running on Go (not g0, not gsignal) stacks, and it contains
corrections for what it detected.
The detection works by changing the C prologue to use a different
stack guard word in the G than Go prologue does. On the g0 and
gsignal stacks, that stack guard word is set to the usual
stack guard value. But on ordinary Go stacks, that stack
guard word is set to ^0, which will make any stack split
check fail. The C prologue then calls morestackc instead
of morestack, and morestackc aborts the program with
a message about running C code on a Go stack.
This check catches all C code running on the Go stack
except NOSPLIT code. The NOSPLIT code is allowed,
so the check is complete. Since it is a dynamic check,
the code must execute to be caught. But unlike the static
checks we've been using in cmd/ld, the dynamic check
works with function pointers and other indirect calls.
For example it caught sigpanic being pushed onto Go
stacks in the signal handlers.
Fixes#8667.
LGTM=khr, iant
R=golang-codereviews, khr, iant
CC=golang-codereviews, r
https://golang.org/cl/133700043
avoid tight coupling between deferreturn and jmpdefer.
before, jmpdefer knew the exact frame size of deferreturn
in order to pop it off the stack. now, deferreturn passes
jmpdefer a pointer to the frame above it explicitly.
that avoids a magic constant and should be less fragile.
R=r
DELTA=32 (6 added, 3 deleted, 23 changed)
OCL=29801
CL=29804
160 - 75 was just barely not enough for deferproc + morestack.
added enum names and bumped to 256 - 128.
added explanation.
changed a few mal() (garbage-collected) to
malloc()/free() (manually collected).
R=ken
OCL=26981
CL=26981
trying to find all the places where
spans might be recorded.
Free can cascade into complicated
span manipulations that move them
from list to list; the old code had the
possibility of accidentally processing
a span twice or jumping to a different
list, causing an infinite loop.
R=r
DELTA=70 (28 added, 25 deleted, 17 changed)
OCL=23704
CL=23710
mark and sweep, stop the world garbage collector
(intermediate step in the way to ref counting).
can run pretty with an explicit gc after each file.
R=r
DELTA=502 (346 added, 143 deleted, 13 changed)
OCL=20630
CL=20635
run oldstack on g0's stack, just like newstack does,
so that oldstack can free the old stack.
R=r
DELTA=53 (44 added, 0 deleted, 9 changed)
OCL=20404
CL=20433
not number of threads. can still starve all the other threads,
but only by looping, not by waiting in a system call.
fix darwin syscall.Syscall6 bug.
fix chanclient bug.
delete $GOMAXPROCS from network tests.
add stripped down printf, sys.printhex to runtime.
R=r
DELTA=355 (217 added, 36 deleted, 102 changed)
OCL=20017
CL=20019
* rewrite lock implementation to be correct
(tip: never assume that an algorithm you found
in a linux man page is correct.)
* delete unneeded void* arg from clone fn
* replace Rendez with Note
* comment mal better
* use 6c -w, fix warnings
* mark all assembly functions 7
R=r
DELTA=828 (338 added, 221 deleted, 269 changed)
OCL=13884
CL=13886
* kick off new os procs (machs) as needed
* add sys·sleep for testing
* add Lock, Rendez
* properly lock mal, sys·newproc, scheduler
* linux syscall arg #4 is in R10, not CX
* chans are not multithread-safe yet
* multithreading disabled by default;
set $gomaxprocs=2 (or 1000) to turn it on
This should build on OS X but may not.
Rob and I will fix soon after submitting.
TBR=r
OCL=13784
CL=13842
