go/src
Cherry Zhang af8f4062c2 runtime: scan gp._panic in stack scan
In runtime.gopanic, the _panic object p is stack allocated and
referenced from gp._panic. With stack objects, p on stack is dead
at the point preprintpanics runs. gp._panic points to p, but
stack scan doesn't look at gp. Heap scan of gp does look at
gp._panic, but it stops and ignores the pointer as it points to
the stack. So whatever p points to may be collected and clobbered.
We need to scan gp._panic explicitly during stack scan.

To test it reliably, we introduce a GODEBUG mode "clobberfree",
which clobbers the memory content when the GC frees an object.

Fixes #30150.

Change-Id: I11128298f03a89f817faa221421a9d332b41dced
Reviewed-on: https://go-review.googlesource.com/c/161778
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
2019-02-13 15:49:22 +00:00
..
archive
bufio
builtin
bytes
cmd
compress
container
context
crypto
database/sql
debug
encoding
errors
expvar
flag
fmt
go
hash
html
image
index/suffixarray
internal
io
log
math
mime
net
os
path
plugin
reflect
regexp
runtime runtime: scan gp._panic in stack scan 2019-02-13 15:49:22 +00:00
sort
strconv
strings
sync
syscall
testdata
testing
text
time
unicode
unsafe
Make.dist
all.bash
all.bat
all.rc
androidtest.bash
bootstrap.bash
buildall.bash
clean.bash
clean.bat
clean.rc
cmp.bash
iostest.bash
make.bash
make.bat
make.rc
naclmake.bash
nacltest.bash
race.bash
race.bat
run.bash
run.bat
run.rc