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authorPeter Oberparleiter <oberpar@linux.vnet.ibm.com>2009-07-05 12:08:06 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-07-06 13:57:03 -0700
commitf386c61fe1a1f36f0e434f1b577e6b112698caf7 (patch)
tree40578bc7a067fdb397c1d6dfcc165a433a7c4933 /arch/x86
parent28df30e61b46a33d1f0bb60757747396886ef687 (diff)
gcov: exclude code operating in userspace from profiling
Fix for this issue on x86_64: rostedt@goodmis.org wrote: > On bootup of the latest kernel my init segfaults. Debugging it, > I found that vread_tsc (a vsyscall) increments some strange > kernel memory: > > 0000000000000000 <vread_tsc>: > 0: 55 push %rbp > 1: 48 ff 05 00 00 00 00 incq 0(%rip) > # 8 <vread_tsc+0x8> > 4: R_X86_64_PC32 .bss+0x3c > 8: 48 89 e5 mov %rsp,%rbp > b: 66 66 90 xchg %ax,%ax > e: 48 ff 05 00 00 00 00 incq 0(%rip) > # 15 <vread_tsc+0x15> > 11: R_X86_64_PC32 .bss+0x44 > 15: 66 66 90 xchg %ax,%ax > 18: 48 ff 05 00 00 00 00 incq 0(%rip) > # 1f <vread_tsc+0x1f> > 1b: R_X86_64_PC32 .bss+0x4c > 1f: 0f 31 rdtsc > > > Those "incq" is very bad to happen in vsyscall memory, since > userspace can not modify it. You need to make something prevent > profiling of vsyscall memory (like I do with ftrace). Signed-off-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Reported-by: Steven Rostedt <rostedt@goodmis.org> Tested-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/kernel/Makefile2
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 6c327b852e2..430d5b24af7 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -26,6 +26,8 @@ CFLAGS_tsc.o := $(nostackp)
CFLAGS_paravirt.o := $(nostackp)
GCOV_PROFILE_vsyscall_64.o := n
GCOV_PROFILE_hpet.o := n
+GCOV_PROFILE_tsc.o := n
+GCOV_PROFILE_paravirt.o := n
obj-y := process_$(BITS).o signal.o entry_$(BITS).o
obj-y += traps.o irq.o irq_$(BITS).o dumpstack_$(BITS).o