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
