x86/traps: Mark do_int3() NOKPROBE_SYMBOL

Since kprobe_int3_handler() is called in do_int3(), probing do_int3()
can cause a breakpoint recursion and crash the kernel. Therefore,
do_int3() should be marked as NOKPROBE_SYMBOL.

Fixes: 21e28290 ("x86/traps: Split int3 handler up")
Signed-off-by: Li Huafei <lihuafei1@huawei.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20220310120915.63349-1-lihuafei1@huawei.com

arch/x86/kernel/traps.c

@@ -659,6 +659,7 @@ static bool do_int3(struct pt_regs *regs)
 
 	return res == NOTIFY_STOP;
 }
+NOKPROBE_SYMBOL(do_int3);
 
 static void do_int3_user(struct pt_regs *regs)
 {