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Commit 2b7d0390 authored by Ingo Molnar's avatar Ingo Molnar
Browse files

tracing: branch tracer, fix vdso crash 



Impact: fix bootup crash

the branch tracer missed arch/x86/vdso/vclock_gettime.c from
disabling tracing, which caused such bootup crashes:

  [  201.840097] init[1]: segfault at 7fffed3fe7c0 ip 00007fffed3fea2e sp 000077

also clean up the ugly ifdefs in arch/x86/kernel/vsyscall_64.c by
creating DISABLE_UNLIKELY_PROFILE facility for code to turn off
instrumentation on a per file basis.

Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent f88c4ae9

arch/x86/kernel/vsyscall_64.c

+2 −7
Original line number Diff line number Diff line
@@ -17,13 +17,8 @@ 
 *  want per guest time just set the kernel.vsyscall64 sysctl to 0.

 */



/* Protect userspace from profiling */

#ifdef CONFIG_TRACE_UNLIKELY_PROFILE

# undef likely

# undef unlikely

# define likely(x)		likely_notrace(x)

# define unlikely(x)		unlikely_notrace(x)

#endif

/* Disable profiling for userspace code: */

#define DISABLE_UNLIKELY_PROFILE



#include <linux/time.h>

#include <linux/init.h>

arch/x86/vdso/vclock_gettime.c

+3 −0
Original line number Diff line number Diff line
@@ -9,6 +9,9 @@ 
 * Also alternative() doesn't work.

 */



/* Disable profiling for userspace code: */

#define DISABLE_UNLIKELY_PROFILE



#include <linux/kernel.h>

#include <linux/posix-timers.h>

#include <linux/time.h>

include/linux/compiler.h

+5 −1
Original line number Diff line number Diff line
@@ -59,7 +59,11 @@ extern void __chk_io_ptr(const volatile void __iomem *); 
 * specific implementations come from the above header files

 */



#ifdef CONFIG_TRACE_UNLIKELY_PROFILE

/*

 * Note: DISABLE_UNLIKELY_PROFILE can be used by special lowlevel code

 * to disable branch tracing on a per file basis.

 */

#if defined(CONFIG_TRACE_UNLIKELY_PROFILE) && !defined(DISABLE_UNLIKELY_PROFILE)

struct ftrace_likely_data {

	const char *func;

	const char *file;