ftrace/x86: skip over the breakpoint for ftrace caller (ab4ead02) · Commits · 戴 / test

In commit "ftrace: Use breakpoint method to update ftrace caller", we choose to use breakpoint method to update the ftrace caller. But we also need to skip over the breakpoint in function ftrace_int3_handler() for them. Otherwise weird things would happen. Cc: stable@vger.kernel.org # 3.5+ Signed-off-by:

Kevin Hao <haokexin@gmail.com> Signed-off-by:

Steven Rostedt <rostedt@goodmis.org>

arch/x86/kernel/ftrace.c

+13 −1

Original line number	Diff line number	Diff line
		@@ -248,6 +248,15 @@ int ftrace_update_ftrace_func(ftrace_func_t func)
		return ret;
		}

		static int is_ftrace_caller(unsigned long ip)
		{
		if (ip == (unsigned long)(&ftrace_call) \|\|
		ip == (unsigned long)(&ftrace_regs_call))
		return 1;

		return 0;
		}

		/*
		* A breakpoint was added to the code address we are about to
		* modify, and this is the handle that will just skip over it.
		@@ -257,10 +266,13 @@ int ftrace_update_ftrace_func(ftrace_func_t func)
		*/
		int ftrace_int3_handler(struct pt_regs *regs)
		{
		unsigned long ip;

		if (WARN_ON_ONCE(!regs))
		return 0;

		if (!ftrace_location(regs->ip - 1))
		ip = regs->ip - 1;
		if (!ftrace_location(ip) && !is_ftrace_caller(ip))
		return 0;

		regs->ip += MCOUNT_INSN_SIZE - 1;

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