diff options
| author | Rusty Russell <rusty@rustcorp.com.au> | 2013-09-05 17:45:53 +0930 |
|---|---|---|
| committer | Rusty Russell <rusty@rustcorp.com.au> | 2013-09-06 08:09:27 +0930 |
| commit | 98fb4e5e6b100a247ce2dbf2d1699726fdcdef20 (patch) | |
| tree | caed1f9e084f2e8f7d1a38b8705d2c7831da2ee8 | |
| parent | 4623c28e222d82f87537ef66db61ebcfbd8306db (diff) | |
lguest: fix guest kernel stack overflow when TF bit set.
The symptoms are that running gdb on a binary causes the guest to
overflow the kernels stack (after some period of time), resulting in
it finally being killed with a "Bad address" message.
Reported-by: Sakari Ailus <sakari.ailus@iki.fi>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
| -rw-r--r-- | drivers/lguest/interrupts_and_traps.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/drivers/lguest/interrupts_and_traps.c b/drivers/lguest/interrupts_and_traps.c index 28433a155d6..70dfcdc29f1 100644 --- a/drivers/lguest/interrupts_and_traps.c +++ b/drivers/lguest/interrupts_and_traps.c @@ -140,6 +140,16 @@ static void set_guest_interrupt(struct lg_cpu *cpu, u32 lo, u32 hi, cpu->regs->eip = idt_address(lo, hi); /* + * Trapping always clears these flags: + * TF: Trap flag + * VM: Virtual 8086 mode + * RF: Resume + * NT: Nested task. + */ + cpu->regs->eflags &= + ~(X86_EFLAGS_TF|X86_EFLAGS_VM|X86_EFLAGS_RF|X86_EFLAGS_NT); + + /* * There are two kinds of interrupt handlers: 0xE is an "interrupt * gate" which expects interrupts to be disabled on entry. */ |