* [PATCH v2][GIT PULL][v3.5] ftrace: Make all inline tags also include notrace
@ 2012-06-18 14:01 Steven Rostedt
2012-06-20 12:27 ` Ingo Molnar
0 siblings, 1 reply; 2+ messages in thread
From: Steven Rostedt @ 2012-06-18 14:01 UTC (permalink / raw)
To: LKML; +Cc: Ingo Molnar, Andrew Morton, Frederic Weisbecker, Fengguang Wu
Ingo,
I updated the change log as you recommended, there was no code change.
-- Steve
Please pull the latest tip/perf/urgent-2 tree, which can be found at:
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git
tip/perf/urgent-2
Head SHA1: 93b3cca1ccd30b1ad290951a3fc7c10c73db7313
Steven Rostedt (1):
ftrace: Make all inline tags also include notrace
----
include/linux/compiler-gcc.h | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
---------------------------
commit 93b3cca1ccd30b1ad290951a3fc7c10c73db7313
Author: Steven Rostedt <rostedt@goodmis.org>
Date: Thu Jun 14 10:54:28 2012 -0400
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 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
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH v2][GIT PULL][v3.5] ftrace: Make all inline tags also include notrace
2012-06-18 14:01 [PATCH v2][GIT PULL][v3.5] ftrace: Make all inline tags also include notrace Steven Rostedt
@ 2012-06-20 12:27 ` Ingo Molnar
0 siblings, 0 replies; 2+ messages in thread
From: Ingo Molnar @ 2012-06-20 12:27 UTC (permalink / raw)
To: Steven Rostedt
Cc: LKML, Ingo Molnar, Andrew Morton, Frederic Weisbecker, Fengguang Wu
* Steven Rostedt <rostedt@goodmis.org> wrote:
> Ingo,
>
> I updated the change log as you recommended, there was no code change.
>
> -- Steve
>
> Please pull the latest tip/perf/urgent-2 tree, which can be found at:
>
> git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git
> tip/perf/urgent-2
>
> Head SHA1: 93b3cca1ccd30b1ad290951a3fc7c10c73db7313
>
>
> Steven Rostedt (1):
> ftrace: Make all inline tags also include notrace
>
> ----
> include/linux/compiler-gcc.h | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
> ---------------------------
> commit 93b3cca1ccd30b1ad290951a3fc7c10c73db7313
> Author: Steven Rostedt <rostedt@goodmis.org>
> Date: Thu Jun 14 10:54:28 2012 -0400
>
> 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 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
Pulled, thanks Steve!
Ingo
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2012-06-18 14:01 [PATCH v2][GIT PULL][v3.5] ftrace: Make all inline tags also include notrace Steven Rostedt
2012-06-20 12:27 ` Ingo Molnar
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