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 <wfg@linux.intel.com>
Tested-by: Fengguang Wu <wfg@linux.intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
index e5834aa24b9ec2a287026d58caf097bf438df055..6a6d7aefe12d6e61cae9e44b13aea1ed74ebedda 100644 (file)
--- 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