From 93b3cca1ccd30b1ad290951a3fc7c10c73db7313 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Thu, 14 Jun 2012 10:54:28 -0400 Subject: ftrace: Make all inline tags also include notrace Commit 5963e317b1e9d2a ("ftrace/x86: Do not change stacks in DEBUG when calling lockdep") prevented lockdep calls from the int3 breakpoint handler from reseting the stack if a function that was called was in the process of being converted for tracing and had a breakpoint on it. The idea is, before calling the lockdep code, do a load_idt() to the special IDT that kept the breakpoint stack from reseting. This worked well as a quick fix for this kernel release, until a certain config caused a lockup in the function tracer start up tests. Investigating it, I found that the load_idt that was used to prevent the int3 from changing stacks was itself being traced! Even though the config had CONFIG_OPTIMIZE_INLINING disabled, and all 'inline' tags were set to always inline, there were still cases that it did not inline! This was caused by CONFIG_PARAVIRT_GUEST, where it would add a pointer to the native_load_idt() which made that function to be traced. Commit 45959ee7aa645815a ("ftrace: Do not function trace inlined functions") only touched the 'inline' tags when CONFIG_OPMITIZE_INLINING was enabled. PARAVIRT_GUEST shows that this was not enough and we need to also mark always_inline with notrace as well. Reported-by: Fengguang Wu Tested-by: Fengguang Wu Signed-off-by: Steven Rostedt diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h index e5834aa..6a6d7ae 100644 --- a/include/linux/compiler-gcc.h +++ b/include/linux/compiler-gcc.h @@ -47,9 +47,9 @@ */ #if !defined(CONFIG_ARCH_SUPPORTS_OPTIMIZED_INLINING) || \ !defined(CONFIG_OPTIMIZE_INLINING) || (__GNUC__ < 4) -# define inline inline __attribute__((always_inline)) -# define __inline__ __inline__ __attribute__((always_inline)) -# define __inline __inline __attribute__((always_inline)) +# define inline inline __attribute__((always_inline)) notrace +# define __inline__ __inline__ __attribute__((always_inline)) notrace +# define __inline __inline __attribute__((always_inline)) notrace #else /* A lot of inline functions can cause havoc with function tracing */ # define inline inline notrace -- cgit v0.10.2