Hi,
I'd like some review of this suggestion to fix:
6313816 SA windows unaligned address exception
webrev:
http://cr.openjdk.java.net/~kevinw/6313816/webrev/
This bug is a long-standing annoyance, mainly shown by
using jstack -m
Already fixed on Linux with additional sanity checks on
ebp/rbp values in
e.g. LinuxX86CFrame.sender()
On Windows there isn't such a convenient place to put
these checks, as they
call getAddressValue() which is only part of the specific
debugger interfaces
such as LinuxDebugger, WindbgDebugger, etc.. and on
Windows we use
X86CFrame and AMD64CFrame. These are constructed with
only a
CDebugger, there is no "WinXXXFrame" class - perhaps there
should be!
That's what I've tried here, by renaming e.g. X86CFrame
to WinX86CFrame,
and adding the extra sanity checks as we already have in
LinuxX86CFrame.
As files have move thed diff isn't obvious, but in common
with some previous changes
the new bits are x86 and x64 versions of these:
+ // Check alignment of rbp
+ if ( dbg.getAddressValue(rbp) % ADDRESS_SIZE != 0) {
+ return null;
+ }
+
and
- if (nextRBP == null) {
+ if (nextRBP == null || nextRBP.lessThanOrEqual(rbp)) {
This additional symmetry between the platforms seems to
make sense, and
should help any future changes.
Thanks
Kevin
