kprobes: dont steal interrupts from vm86

PATCH New Stas Sergeev 1 participant 1 message Nov 9, 2004

lore

Share & tools

lore

Stas Sergeev

author

2004-11-09 19:01 UTC #0 lore raw

PATCH 1/1 kprobes: dont steal interrupts from vm86

Hello.

With kprobes enabled, vm86 doesn't feel good. The problem is that kprobes steal the interrupts (mainly int3 I think) from it for no good reason.
The attached patch fixes the problem by checking the VM flag where it makes sense.

Andrew, can this please be applied?

Signed-off-by Stas Sergeev <[email protected]>

linux/arch/i386/kernel/traps.c renamed from arch/i386/kernel/traps.c +12 -6

@@ -408,7 +408,8 @@
 #define DO_ERROR(trapnr, signr, str, name) \
 asmlinkage void do_##name(struct pt_regs * regs, long error_code) \
 { \
-	if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
+	if (!(regs->eflags & VM_MASK) && \
+		notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
 						== NOTIFY_STOP) \
 		return; \
 	do_trap(trapnr, signr, str, 0, regs, error_code, NULL); \

@@ -422,7 +423,8 @@
 	info.si_errno = 0; \
 	info.si_code = sicode; \
 	info.si_addr = (void __user *)siaddr; \
-	if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
+	if (!(regs->eflags & VM_MASK) && \
+		notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
 						== NOTIFY_STOP) \
 		return; \
 	do_trap(trapnr, signr, str, 0, regs, error_code, &info); \

@@ -431,7 +433,8 @@
 #define DO_VM86_ERROR(trapnr, signr, str, name) \
 asmlinkage void do_##name(struct pt_regs * regs, long error_code) \
 { \
-	if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
+	if (!(regs->eflags & VM_MASK) && \
+		notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
 						== NOTIFY_STOP) \
 		return; \
 	do_trap(trapnr, signr, str, 1, regs, error_code, NULL); \

@@ -445,7 +448,8 @@
 	info.si_errno = 0; \
 	info.si_code = sicode; \
 	info.si_addr = (void __user *)siaddr; \
-	if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
+	if (!(regs->eflags & VM_MASK) && \
+		notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
 						== NOTIFY_STOP) \
 		return; \
 	do_trap(trapnr, signr, str, 1, regs, error_code, &info); \

@@ -652,7 +656,8 @@
 #ifdef CONFIG_KPROBES
 asmlinkage int do_int3(struct pt_regs *regs, long error_code)
 {
-	if (notify_die(DIE_INT3, "int3", regs, error_code, 3, SIGTRAP)
+	if (!(regs->eflags & VM_MASK) &&
+		notify_die(DIE_INT3, "int3", regs, error_code, 3, SIGTRAP)
 			== NOTIFY_STOP)
 		return 1;
 	/* This is an interrupt gate, because kprobes wants interrupts

@@ -693,7 +698,8 @@
 
 	__asm__ __volatile__("movl %%db6,%0" : "=r" (condition));
 
-	if (notify_die(DIE_DEBUG, "debug", regs, condition, error_code,
+	if (!(regs->eflags & VM_MASK) && 
+		notify_die(DIE_DEBUG, "debug", regs, condition, error_code,
 					SIGTRAP) == NOTIFY_STOP)
 		return;
 	/* It's safe to allow irq's after DR6 has been saved */