Re: [PATCH -next] optprobes: fix kconfig depends/selects

From: Masami Hiramatsu
Date: Sun Sep 12 2010 - 21:06:30 EST


(2010/09/12 19:49), Felipe Contreras wrote:
> On Thu, Aug 12, 2010 at 10:26 PM, Randy Dunlap <randy.dunlap@xxxxxxxxxx> wrote:
>> From: Randy Dunlap <randy.dunlap@xxxxxxxxxx>
>>
>> KALLSYMS and KALLSYMS_ALL depend on DEBUG_KERNEL, so add that dependency.
>> KALLSYMS_ALL depends on KALLSYMS, so select both of them, not just KALLSYMS_ALL.
>>
>> warning: (OPTPROBES && KPROBES && HAVE_OPTPROBES && !PREEMPT || MTD_UBI_DEBUG && MTD && SYSFS && MTD_UBI || UBIFS_FS_DEBUG && MISC_FILESYSTEMS && UBIFS_FS || LOCKDEP && DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT || LATENCYTOP && HAVE_LATENCYTOP_SUPPORT) selects KALLSYMS_ALL which has unmet direct dependencies (DEBUG_KERNEL && KALLSYMS)
>>
>> Signed-off-by: Randy Dunlap <randy.dunlap@xxxxxxxxxx>
>> Cc: Ananth N Mavinakayanahalli <ananth@xxxxxxxxxx>
>> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@xxxxxxxxx>
>> Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
>> Cc: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
>> ---
>> arch/Kconfig | 2 ++
>> 1 file changed, 2 insertions(+)
>>
>> --- linux-next-20100810.orig/arch/Kconfig
>> +++ linux-next-20100810/arch/Kconfig
>> @@ -45,6 +45,8 @@ config OPTPROBES
>> def_bool y
>> depends on KPROBES && HAVE_OPTPROBES
>> depends on !PREEMPT
>> + depends on DEBUG_KERNEL
>> + select KALLSYMS
>> select KALLSYMS_ALL
>>
>> config HAVE_EFFICIENT_UNALIGNED_ACCESS
>> --
>
> This causes another problem:
>
> arch/Kconfig:33:error: recursive dependency detected!
> arch/Kconfig:33: symbol KPROBES depends on KALLSYMS
> init/Kconfig:825: symbol KALLSYMS is selected by OPTPROBES
> arch/Kconfig:44: symbol OPTPROBES depends on KPROBES
>
> The 'select KALLSYMS' is redundant.
>
> Otherwise: Signed-off-by: Felipe Contreras <felipe.contreras@xxxxxxxxx>
>

Thanks, let me clear the dependency;
Kprobes uses kallsyms_lookup for finding target function and checking
instruction boundary, thus CONFIG_KPROBES should select CONFIG_KALLSYMS
and CONFIG_KALLSYMS_ALL.
Optprobe is a optional feature which is supported on x86 arch, and
it also uses kallsyms_lookup for checking instructions in the target
function. Anyway, since optprobe itself is depends on kprobes, it doesn't
need to select both of KALLSYMS/KALLSYMS_ALL.

Thank you,

--
Masami HIRAMATSU
2nd Dept. Linux Technology Center
Hitachi, Ltd., Systems Development Laboratory
E-mail: masami.hiramatsu.pt@xxxxxxxxxxx
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