Re: [PATCH 2/2] kprobes: check CONFIG_FREEZER instead of CONFIG_PM

[Masami Hiramatsu <mhiramat@redhat.com>]

Rafael J. Wysocki wrote:
> On Tuesday 10 February 2009, Masami Hiramatsu wrote:
>> Rafael J. Wysocki wrote:
>>> On Tuesday 10 February 2009, Ingo Molnar wrote:
>>>> * Masami Hiramatsu <mhiramat@redhat.com> wrote:
>>>>
>>>>> Ingo Molnar wrote:
>>>>>> * Len Brown <lenb@kernel.org> wrote:
>>>>>>
>>>>>>>>> Check CONFIG_FREEZER instead of CONFIG_PM because kprobe booster
>>>>>>>>> depends on freeze_processes() and thaw_processes() when CONFIG_PREEMPT=y.
>>>>>>>>>
>>>>>>>>> This fixes a linkage error which occurs when CONFIG_PREEMPT=y, CONFIG_PM=y
>>>>>>>>> and CONFIG_FREEZER=n.
>>>>>>>>>
>>>>>>>>> Reported-by: Cheng Renquan <crquan@gmail.com>
>>>>>>>>> Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
>>>>>>>>> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
>>>>>>>>> ---
>>>>>>>>>  arch/ia64/kernel/kprobes.c |    2 +-
>>>>>>>>>  arch/x86/kernel/kprobes.c  |    2 +-
>>>>>>>>>  kernel/kprobes.c           |    2 +-
>>>>>>>>>  3 files changed, 3 insertions(+), 3 deletions(-)
>>>>>>>> looks good, the x86 bits:
>>>>>>>>
>>>>>>>> Acked-by: Ingo Molnar <mingo@elte.hu>
>>>>>>> man, we have too many config options:-)
>>>>>> the non-x86 bits (kernel/kprobes.c) are crappy though, and broke -rc4
>>>>>> allnoconfig:
>>>>>>
>>>>>> kernel/built-in.o: In function `collect_garbage_slots':
>>>>>> kprobes.c:(.kprobes.text+0x16e4): undefined reference to `freeze_processes'
>>>>>> kprobes.c:(.kprobes.text+0x16f2): undefined reference to `thaw_processes'
>>>>>> kprobes.c:(.kprobes.text+0x176b): undefined reference to `thaw_processes'
>>>>> Hmm, it seems that kernel/power/built-in.o was not linked to .tmp_vmlinux1.
>>>>>
>>>>>   ld -m elf_i386 --build-id -o .tmp_vmlinux1 -T arch/x86/kernel/vmlinux.lds
>>>>> arch/x86/kernel/head_32.o arch/x86/kernel/head32.o arch/x86/kernel/head.o
>>>>> arch/x86/kernel/init_task.o  init/built-in.o --start-group  usr/built-in.o
>>>>> arch/x86/kernel/built-in.o  arch/x86/mm/built-in.o  arch/x86/mach-default/built-in.o
>>>>> arch/x86/crypto/built-in.o  arch/x86/vdso/built-in.o  kernel/built-in.o
>>>>> mm/built-in.o  fs/built-in.o  ipc/built-in.o  security/built-in.o  crypto/built-in.o
>>>>> block/built-in.o  lib/lib.a  arch/x86/lib/lib.a  lib/built-in.o
>>>>> arch/x86/lib/built-in.o  drivers/built-in.o  sound/built-in.o  firmware/built-in.o
>>>>> arch/x86/pci/built-in.o  net/built-in.o --end-group
>>>>> kernel/built-in.o: In function `collect_garbage_slots':
>>>>> kprobes.c:(.kprobes.text+0x16e4): undefined reference to `freeze_processes'
>>>>> kprobes.c:(.kprobes.text+0x16f2): undefined reference to `thaw_processes'
>>>>> kprobes.c:(.kprobes.text+0x176b): undefined reference to `thaw_processes'
>>>>>
>>>>> At kernel/Makefile:53, I can see
>>>>>
>>>>> obj-$(CONFIG_PM) += power/
>>>>>
>>>>> but CONFIG_PM was not set in config
>>>> Sounds plausible. We need a fix for this - it's broken upstream.
>>> Hmm.  Can || be used under obj-$() ?
>> I think just adding a line "obj-$(CONFIG_FREEZER) += power/" is enough.
>> (you can see similar lines of "trace/" at the bottom of obj- lines
>>  in kernel/Makefile )
> 
> Indeed, thanks.
> 
> So, something like the appended patch should help, I think.
> 
> Rafael

Thank you for fixing. I've tested it.

Tested-by: Masami Hiramatsu <mhiramat@redhat.com>


> 
> ---
>  kernel/Makefile       |    1 +
>  kernel/power/Makefile |    2 +-
>  2 files changed, 2 insertions(+), 1 deletion(-)
> 
> Index: linux-2.6/kernel/Makefile
> ===================================================================
> --- linux-2.6.orig/kernel/Makefile
> +++ linux-2.6/kernel/Makefile
> @@ -51,6 +51,7 @@ obj-$(CONFIG_UID16) += uid16.o
>  obj-$(CONFIG_MODULES) += module.o
>  obj-$(CONFIG_KALLSYMS) += kallsyms.o
>  obj-$(CONFIG_PM) += power/
> +obj-$(CONFIG_FREEZER) += power/
>  obj-$(CONFIG_BSD_PROCESS_ACCT) += acct.o
>  obj-$(CONFIG_KEXEC) += kexec.o
>  obj-$(CONFIG_BACKTRACE_SELF_TEST) += backtracetest.o
> Index: linux-2.6/kernel/power/Makefile
> ===================================================================
> --- linux-2.6.orig/kernel/power/Makefile
> +++ linux-2.6/kernel/power/Makefile
> @@ -3,7 +3,7 @@ ifeq ($(CONFIG_PM_DEBUG),y)
>  EXTRA_CFLAGS	+=	-DDEBUG
>  endif
>  
> -obj-y				:= main.o
> +obj-$(CONFIG_PM)		+= main.o
>  obj-$(CONFIG_PM_SLEEP)		+= console.o
>  obj-$(CONFIG_FREEZER)		+= process.o
>  obj-$(CONFIG_HIBERNATION)	+= swsusp.o disk.o snapshot.o swap.o user.o

-- 
Masami Hiramatsu

Software Engineer
Hitachi Computer Products (America) Inc.
Software Solutions Division

e-mail: mhiramat@redhat.com