Opened 12 years ago
Closed 8 years ago
#10377 closed defect (obsolete)
x86 debug registers don't work reliably in a guest OS
| Reported by: | Eugene153 | Owned by: | |
|---|---|---|---|
| Component: | other | Version: | VirtualBox 4.1.10 |
| Keywords: | x86 debug registers | Cc: | |
| Guest type: | other | Host type: | other |
Description
Some of x86 debug register events appears lost and not delivered to a guest OS.
To reproduce: Use gdb on a Linux guest to run a simple program like this:
#include <stdio.h>
int main(int argc, char ** argv) {
char ch = 0;
for (;;) {
ch = ch + 1;
printf("%d\n", ch);
}
return 0;
}
set a hardware breakpoint:
(gdb) watch ch Hardware watchpoint 2: ch (gdb)
do cont until the breakpoint fails to trigger, e.g.:
(gdb) cont
Continuing.
111
112
Hardware watchpoint 2: ch
Old value = 111 'o'
New value = 113 'q'
main (argc=1, argv=0x7fffffffe638) at t.c:8
8 printf("%d\n", ch);
(gdb)
in this case writing 112 to ch did not trigger the breakpoint.
The problem appears reproducible with any host, guest or debugger.
Change History (2)
comment:1 by , 12 years ago
comment:2 by , 8 years ago
| Resolution: | → obsolete |
|---|---|
| Status: | new → closed |
Please reopen if still relevant with a recent VirtualBox release.
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Duplicate of #477? Is VT-x / AMD-V enabled for your VM? Please attach a VBox.log file.