Hi Andrew,
I found a bug of kprobes in i386.
Kprobe-booster doesn't work if CONFIG_PREEMPT is not set.
Because pre_preempt_count is always 0.
Boostability have been disabled when removing '#ifdef
CONFIG_PREEMPT' I think.
This bug doesn't cause a kernel panic.
Regards,
Satoshi Oshima
Signed-off-by: Satoshi Oshima <[email protected]>
diff -Narup linux-2.6.17-rc3-mm1.orig/arch/i386/kernel/kprobes.c kprobes-i386-bugfix/arch/i386/kernel/kprobes.c
--- linux-2.6.17-rc3-mm1.orig/arch/i386/kernel/kprobes.c 2006-05-04 12:34:46.000000000 -0400
+++ kprobes-i386-bugfix/arch/i386/kernel/kprobes.c 2006-05-12 15:41:23.000000000 -0400
@@ -257,7 +257,11 @@ static int __kprobes kprobe_handler(stru
int ret = 0;
kprobe_opcode_t *addr;
struct kprobe_ctlblk *kcb;
+#ifdef CONFIG_PREEMPT
unsigned pre_preempt_count = preempt_count();
+#else
+ unsigned pre_preempt_count = 1;
+#endif
addr = (kprobe_opcode_t *)(regs->eip - sizeof(kprobe_opcode_t));