From: Kevin Hao Date: Wed, 23 Oct 2013 12:58:16 +0000 (+0800) Subject: ftrace/x86: skip over the breakpoint for ftrace caller X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=ab4ead02ec235d706d0611d8741964628291237e;p=linux-beck.git ftrace/x86: skip over the breakpoint for ftrace caller In commit 8a4d0a687a59 "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 Signed-off-by: Steven Rostedt --- diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c index 42a392a9fd02..d4bdd253fea7 100644 --- a/arch/x86/kernel/ftrace.c +++ b/arch/x86/kernel/ftrace.c @@ -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;