| Message ID | 20210517034430.9569-1-rdunlap@infradead.org |
|---|---|
| State | Not Applicable |
| Headers | show |
| Series | LOCKDEP: use depends on LOCKDEP_SUPPORT instead of $ARCH list | expand |
* Randy Dunlap <rdunlap@infradead.org> wrote: > Both arch/um/ and arch/xtensa/ cause a Kconfig warning for LOCKDEP. > These arch-es select LOCKDEP_SUPPORT but they are not listed as one > of the arch-es that LOCKDEP depends on. > > Since (16) arch-es define the Kconfig symbol LOCKDEP_SUPPORT if they > intend to have LOCKDEP support, replace the awkward list of > arch-es that LOCKDEP depends on with the LOCKDEP_SUPPORT symbol. > > Fixes this kconfig warning: (for both um and xtensa) > > WARNING: unmet direct dependencies detected for LOCKDEP > Depends on [n]: DEBUG_KERNEL [=y] && LOCK_DEBUGGING_SUPPORT [=y] && (FRAME_POINTER [=n] || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86) > Selected by [y]: > - PROVE_LOCKING [=y] && DEBUG_KERNEL [=y] && LOCK_DEBUGGING_SUPPORT [=y] > - LOCK_STAT [=y] && DEBUG_KERNEL [=y] && LOCK_DEBUGGING_SUPPORT [=y] > - DEBUG_LOCK_ALLOC [=y] && DEBUG_KERNEL [=y] && LOCK_DEBUGGING_SUPPORT [=y] > > Signed-off-by: Randy Dunlap <rdunlap@infradead.org> > Cc: Peter Zijlstra <peterz@infradead.org> > Cc: Ingo Molnar <mingo@redhat.com> > Cc: Will Deacon <will@kernel.org> > Cc: Waiman Long <longman@redhat.com> > Cc: Boqun Feng <boqun.feng@gmail.com> > Cc: Chris Zankel <chris@zankel.net> > Cc: Max Filippov <jcmvbkbc@gmail.com> > Cc: linux-xtensa@linux-xtensa.org > Cc: Johannes Berg <johannes@sipsolutions.net> > Cc: Jeff Dike <jdike@addtoit.com> > Cc: Richard Weinberger <richard@nod.at> > Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com> > Cc: linux-um@lists.infradead.org > --- > lib/Kconfig.debug | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > --- linux-next-20210514.orig/lib/Kconfig.debug > +++ linux-next-20210514/lib/Kconfig.debug > @@ -1383,7 +1383,7 @@ config LOCKDEP > bool > depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT > select STACKTRACE > - depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86 > + depends on FRAME_POINTER || LOCKDEP_SUPPORT Ok - the FRAME_POINTER bit is weird. Are there any architectures that have FRAME_POINTER defined but no LOCKDEP_SUPPORT? Thanks, Ingo
On 5/17/21 3:11 AM, Ingo Molnar wrote: > * Randy Dunlap <rdunlap@infradead.org> wrote: > >> Both arch/um/ and arch/xtensa/ cause a Kconfig warning for LOCKDEP. >> These arch-es select LOCKDEP_SUPPORT but they are not listed as one >> of the arch-es that LOCKDEP depends on. >> >> Since (16) arch-es define the Kconfig symbol LOCKDEP_SUPPORT if they >> intend to have LOCKDEP support, replace the awkward list of >> arch-es that LOCKDEP depends on with the LOCKDEP_SUPPORT symbol. >> >> Fixes this kconfig warning: (for both um and xtensa) >> >> WARNING: unmet direct dependencies detected for LOCKDEP >> Depends on [n]: DEBUG_KERNEL [=y] && LOCK_DEBUGGING_SUPPORT [=y] && (FRAME_POINTER [=n] || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86) >> Selected by [y]: >> - PROVE_LOCKING [=y] && DEBUG_KERNEL [=y] && LOCK_DEBUGGING_SUPPORT [=y] >> - LOCK_STAT [=y] && DEBUG_KERNEL [=y] && LOCK_DEBUGGING_SUPPORT [=y] >> - DEBUG_LOCK_ALLOC [=y] && DEBUG_KERNEL [=y] && LOCK_DEBUGGING_SUPPORT [=y] >> >> Signed-off-by: Randy Dunlap <rdunlap@infradead.org> >> Cc: Peter Zijlstra <peterz@infradead.org> >> Cc: Ingo Molnar <mingo@redhat.com> >> Cc: Will Deacon <will@kernel.org> >> Cc: Waiman Long <longman@redhat.com> >> Cc: Boqun Feng <boqun.feng@gmail.com> >> Cc: Chris Zankel <chris@zankel.net> >> Cc: Max Filippov <jcmvbkbc@gmail.com> >> Cc: linux-xtensa@linux-xtensa.org >> Cc: Johannes Berg <johannes@sipsolutions.net> >> Cc: Jeff Dike <jdike@addtoit.com> >> Cc: Richard Weinberger <richard@nod.at> >> Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com> >> Cc: linux-um@lists.infradead.org >> --- >> lib/Kconfig.debug | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> --- linux-next-20210514.orig/lib/Kconfig.debug >> +++ linux-next-20210514/lib/Kconfig.debug >> @@ -1383,7 +1383,7 @@ config LOCKDEP >> bool >> depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT >> select STACKTRACE >> - depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86 >> + depends on FRAME_POINTER || LOCKDEP_SUPPORT > Ok - the FRAME_POINTER bit is weird. Are there any architectures that have > FRAME_POINTER defined but no LOCKDEP_SUPPORT? LOCK_DEBUGGING_SUPPORT depends on LOCKDEP_SUPPORT. So this patch is equivalent to just delete the second depends-on line. Beside LOCKDEP, LATENCYTOP also have exactly the same depends-on line. So isn't FRAME_POINTER used mainly to support STACK_TRACE? However, LOCK_DEBUGGING_SUPPORT has already included STACK_TRACE_SUPPORT in its dependency. So why there is a FRAME_POINTER dependency? Cheers, Longman
On 5/17/21 12:11 AM, Ingo Molnar wrote: > > * Randy Dunlap <rdunlap@infradead.org> wrote: > >> Both arch/um/ and arch/xtensa/ cause a Kconfig warning for LOCKDEP. >> These arch-es select LOCKDEP_SUPPORT but they are not listed as one >> of the arch-es that LOCKDEP depends on. >> >> Since (16) arch-es define the Kconfig symbol LOCKDEP_SUPPORT if they >> intend to have LOCKDEP support, replace the awkward list of >> arch-es that LOCKDEP depends on with the LOCKDEP_SUPPORT symbol. >> >> Fixes this kconfig warning: (for both um and xtensa) >> >> WARNING: unmet direct dependencies detected for LOCKDEP >> Depends on [n]: DEBUG_KERNEL [=y] && LOCK_DEBUGGING_SUPPORT [=y] && (FRAME_POINTER [=n] || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86) >> Selected by [y]: >> - PROVE_LOCKING [=y] && DEBUG_KERNEL [=y] && LOCK_DEBUGGING_SUPPORT [=y] >> - LOCK_STAT [=y] && DEBUG_KERNEL [=y] && LOCK_DEBUGGING_SUPPORT [=y] >> - DEBUG_LOCK_ALLOC [=y] && DEBUG_KERNEL [=y] && LOCK_DEBUGGING_SUPPORT [=y] >> >> Signed-off-by: Randy Dunlap <rdunlap@infradead.org> >> Cc: Peter Zijlstra <peterz@infradead.org> >> Cc: Ingo Molnar <mingo@redhat.com> >> Cc: Will Deacon <will@kernel.org> >> Cc: Waiman Long <longman@redhat.com> >> Cc: Boqun Feng <boqun.feng@gmail.com> >> Cc: Chris Zankel <chris@zankel.net> >> Cc: Max Filippov <jcmvbkbc@gmail.com> >> Cc: linux-xtensa@linux-xtensa.org >> Cc: Johannes Berg <johannes@sipsolutions.net> >> Cc: Jeff Dike <jdike@addtoit.com> >> Cc: Richard Weinberger <richard@nod.at> >> Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com> >> Cc: linux-um@lists.infradead.org >> --- >> lib/Kconfig.debug | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> --- linux-next-20210514.orig/lib/Kconfig.debug >> +++ linux-next-20210514/lib/Kconfig.debug >> @@ -1383,7 +1383,7 @@ config LOCKDEP >> bool >> depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT >> select STACKTRACE >> - depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86 >> + depends on FRAME_POINTER || LOCKDEP_SUPPORT > > Ok - the FRAME_POINTER bit is weird. Are there any architectures that have > FRAME_POINTER defined but no LOCKDEP_SUPPORT? arch/h8300/ does AFAICT. and arch/parisc/ has user-choosable FRAME_POINTER and no LOCKDEP support.
On 5/17/21 7:02 AM, Waiman Long wrote: > On 5/17/21 3:11 AM, Ingo Molnar wrote: >> * Randy Dunlap <rdunlap@infradead.org> wrote: >> >>> Both arch/um/ and arch/xtensa/ cause a Kconfig warning for LOCKDEP. >>> These arch-es select LOCKDEP_SUPPORT but they are not listed as one >>> of the arch-es that LOCKDEP depends on. >>> >>> Since (16) arch-es define the Kconfig symbol LOCKDEP_SUPPORT if they >>> intend to have LOCKDEP support, replace the awkward list of >>> arch-es that LOCKDEP depends on with the LOCKDEP_SUPPORT symbol. >>> >>> Fixes this kconfig warning: (for both um and xtensa) >>> >>> WARNING: unmet direct dependencies detected for LOCKDEP >>> Depends on [n]: DEBUG_KERNEL [=y] && LOCK_DEBUGGING_SUPPORT [=y] && (FRAME_POINTER [=n] || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86) >>> Selected by [y]: >>> - PROVE_LOCKING [=y] && DEBUG_KERNEL [=y] && LOCK_DEBUGGING_SUPPORT [=y] >>> - LOCK_STAT [=y] && DEBUG_KERNEL [=y] && LOCK_DEBUGGING_SUPPORT [=y] >>> - DEBUG_LOCK_ALLOC [=y] && DEBUG_KERNEL [=y] && LOCK_DEBUGGING_SUPPORT [=y] >>> >>> Signed-off-by: Randy Dunlap <rdunlap@infradead.org> >>> Cc: Peter Zijlstra <peterz@infradead.org> >>> Cc: Ingo Molnar <mingo@redhat.com> >>> Cc: Will Deacon <will@kernel.org> >>> Cc: Waiman Long <longman@redhat.com> >>> Cc: Boqun Feng <boqun.feng@gmail.com> >>> Cc: Chris Zankel <chris@zankel.net> >>> Cc: Max Filippov <jcmvbkbc@gmail.com> >>> Cc: linux-xtensa@linux-xtensa.org >>> Cc: Johannes Berg <johannes@sipsolutions.net> >>> Cc: Jeff Dike <jdike@addtoit.com> >>> Cc: Richard Weinberger <richard@nod.at> >>> Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com> >>> Cc: linux-um@lists.infradead.org >>> --- >>> lib/Kconfig.debug | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> --- linux-next-20210514.orig/lib/Kconfig.debug >>> +++ linux-next-20210514/lib/Kconfig.debug >>> @@ -1383,7 +1383,7 @@ config LOCKDEP >>> bool >>> depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT >>> select STACKTRACE >>> - depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86 >>> + depends on FRAME_POINTER || LOCKDEP_SUPPORT >> Ok - the FRAME_POINTER bit is weird. Are there any architectures that have >> FRAME_POINTER defined but no LOCKDEP_SUPPORT? > > LOCK_DEBUGGING_SUPPORT depends on LOCKDEP_SUPPORT. So this patch is equivalent to just delete the second depends-on line. Beside LOCKDEP, LATENCYTOP also have exactly the same depends-on line. I will attempt to consolidate those. > So isn't FRAME_POINTER used mainly to support STACK_TRACE? However, LOCK_DEBUGGING_SUPPORT has already included STACK_TRACE_SUPPORT in its dependency. So why there is a FRAME_POINTER dependency? I dunno why FRAME_POINTER is there. It was there before this patch. thanks.
On 5/17/21 7:02 AM, Waiman Long wrote: > On 5/17/21 3:11 AM, Ingo Molnar wrote: >> * Randy Dunlap <rdunlap@infradead.org> wrote: >> >>> Both arch/um/ and arch/xtensa/ cause a Kconfig warning for LOCKDEP. >>> These arch-es select LOCKDEP_SUPPORT but they are not listed as one >>> of the arch-es that LOCKDEP depends on. >>> >>> Since (16) arch-es define the Kconfig symbol LOCKDEP_SUPPORT if they >>> intend to have LOCKDEP support, replace the awkward list of >>> arch-es that LOCKDEP depends on with the LOCKDEP_SUPPORT symbol. >>> >>> Fixes this kconfig warning: (for both um and xtensa) >>> >>> WARNING: unmet direct dependencies detected for LOCKDEP >>> Depends on [n]: DEBUG_KERNEL [=y] && LOCK_DEBUGGING_SUPPORT [=y] && (FRAME_POINTER [=n] || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86) >>> Selected by [y]: >>> - PROVE_LOCKING [=y] && DEBUG_KERNEL [=y] && LOCK_DEBUGGING_SUPPORT [=y] >>> - LOCK_STAT [=y] && DEBUG_KERNEL [=y] && LOCK_DEBUGGING_SUPPORT [=y] >>> - DEBUG_LOCK_ALLOC [=y] && DEBUG_KERNEL [=y] && LOCK_DEBUGGING_SUPPORT [=y] >>> >>> Signed-off-by: Randy Dunlap <rdunlap@infradead.org> >>> Cc: Peter Zijlstra <peterz@infradead.org> >>> Cc: Ingo Molnar <mingo@redhat.com> >>> Cc: Will Deacon <will@kernel.org> >>> Cc: Waiman Long <longman@redhat.com> >>> Cc: Boqun Feng <boqun.feng@gmail.com> >>> Cc: Chris Zankel <chris@zankel.net> >>> Cc: Max Filippov <jcmvbkbc@gmail.com> >>> Cc: linux-xtensa@linux-xtensa.org >>> Cc: Johannes Berg <johannes@sipsolutions.net> >>> Cc: Jeff Dike <jdike@addtoit.com> >>> Cc: Richard Weinberger <richard@nod.at> >>> Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com> >>> Cc: linux-um@lists.infradead.org >>> --- >>> lib/Kconfig.debug | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> --- linux-next-20210514.orig/lib/Kconfig.debug >>> +++ linux-next-20210514/lib/Kconfig.debug >>> @@ -1383,7 +1383,7 @@ config LOCKDEP >>> bool >>> depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT >>> select STACKTRACE >>> - depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86 >>> + depends on FRAME_POINTER || LOCKDEP_SUPPORT >> Ok - the FRAME_POINTER bit is weird. Are there any architectures that have >> FRAME_POINTER defined but no LOCKDEP_SUPPORT? > > LOCK_DEBUGGING_SUPPORT depends on LOCKDEP_SUPPORT. So this patch is equivalent to just delete the second depends-on line. Yes, if we disregard the FRAME_POINTER part. > Beside LOCKDEP, LATENCYTOP also have exactly the same depends-on line. True, but I don't get any implication that the same patch applies there. Do you? > So isn't FRAME_POINTER used mainly to support STACK_TRACE? However, LOCK_DEBUGGING_SUPPORT has already included STACK_TRACE_SUPPORT in its dependency. So why there is a FRAME_POINTER dependency? FRAME_POINTER is one way but it does not seem to be required for STACKTRACE_SUPPORT. Do you have any patch suggestions? thanks.
On 5/24/21 3:47 PM, Randy Dunlap wrote: > On 5/17/21 7:02 AM, Waiman Long wrote: >> On 5/17/21 3:11 AM, Ingo Molnar wrote: >>> * Randy Dunlap <rdunlap@infradead.org> wrote: >>> >>>> Both arch/um/ and arch/xtensa/ cause a Kconfig warning for LOCKDEP. >>>> These arch-es select LOCKDEP_SUPPORT but they are not listed as one >>>> of the arch-es that LOCKDEP depends on. >>>> >>>> Since (16) arch-es define the Kconfig symbol LOCKDEP_SUPPORT if they >>>> intend to have LOCKDEP support, replace the awkward list of >>>> arch-es that LOCKDEP depends on with the LOCKDEP_SUPPORT symbol. >>>> >>>> Fixes this kconfig warning: (for both um and xtensa) >>>> >>>> WARNING: unmet direct dependencies detected for LOCKDEP >>>> Depends on [n]: DEBUG_KERNEL [=y] && LOCK_DEBUGGING_SUPPORT [=y] && (FRAME_POINTER [=n] || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86) >>>> Selected by [y]: >>>> - PROVE_LOCKING [=y] && DEBUG_KERNEL [=y] && LOCK_DEBUGGING_SUPPORT [=y] >>>> - LOCK_STAT [=y] && DEBUG_KERNEL [=y] && LOCK_DEBUGGING_SUPPORT [=y] >>>> - DEBUG_LOCK_ALLOC [=y] && DEBUG_KERNEL [=y] && LOCK_DEBUGGING_SUPPORT [=y] >>>> >>>> Signed-off-by: Randy Dunlap <rdunlap@infradead.org> >>>> Cc: Peter Zijlstra <peterz@infradead.org> >>>> Cc: Ingo Molnar <mingo@redhat.com> >>>> Cc: Will Deacon <will@kernel.org> >>>> Cc: Waiman Long <longman@redhat.com> >>>> Cc: Boqun Feng <boqun.feng@gmail.com> >>>> Cc: Chris Zankel <chris@zankel.net> >>>> Cc: Max Filippov <jcmvbkbc@gmail.com> >>>> Cc: linux-xtensa@linux-xtensa.org >>>> Cc: Johannes Berg <johannes@sipsolutions.net> >>>> Cc: Jeff Dike <jdike@addtoit.com> >>>> Cc: Richard Weinberger <richard@nod.at> >>>> Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com> >>>> Cc: linux-um@lists.infradead.org >>>> --- >>>> lib/Kconfig.debug | 2 +- >>>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>> >>>> --- linux-next-20210514.orig/lib/Kconfig.debug >>>> +++ linux-next-20210514/lib/Kconfig.debug >>>> @@ -1383,7 +1383,7 @@ config LOCKDEP >>>> bool >>>> depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT >>>> select STACKTRACE >>>> - depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86 >>>> + depends on FRAME_POINTER || LOCKDEP_SUPPORT >>> Ok - the FRAME_POINTER bit is weird. Are there any architectures that have >>> FRAME_POINTER defined but no LOCKDEP_SUPPORT? >> LOCK_DEBUGGING_SUPPORT depends on LOCKDEP_SUPPORT. So this patch is equivalent to just delete the second depends-on line. > Yes, if we disregard the FRAME_POINTER part. My understanding is that the 2 depends-on statements have an implicit AND. So it is like DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT && (FRAME_POINTER || LOCKDEP_SUPPORT). LOCK_DEBUGGING_SUPPORT is true means the (FRAME_POINTER || LOCKDEP_SUPPORT) will always be true. FRAME_POINTER is true doesn't mean the other dependencies are true. That is why I said it is equivalent to just "DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT". IOW, FRAME_POINTER will play no part here. > >> Beside LOCKDEP, LATENCYTOP also have exactly the same depends-on line. > True, but I don't get any implication that the same patch applies there. > Do you? It is just an observation that I stumble on. It is not related to your patch. >> So isn't FRAME_POINTER used mainly to support STACK_TRACE? However, LOCK_DEBUGGING_SUPPORT has already included STACK_TRACE_SUPPORT in its dependency. So why there is a FRAME_POINTER dependency? > FRAME_POINTER is one way but it does not seem to be required > for STACKTRACE_SUPPORT. > > Do you have any patch suggestions? Is it possible to just get rid of the 2nd depends-on statement? The 2nd depends-on line was introduced by commit 7d37cb2c912d ("lib: fix kconfig dependency on ARCH_WANT_FRAME_POINTER"): diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 2779c29d9981..417c3d3e521b 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -1363,7 +1363,7 @@ config LOCKDEP bool depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT select STACKTRACE - select FRAME_POINTER if !MIPS && !PPC && !ARM && !S390 && !MICROBLAZE && + depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || select KALLSYMS select KALLSYMS_ALL Since STACKTRACE is selected by lockdep, maybe we can just remove the 2nd depends-on line to see if anyone complain. Cheers, Longman
On 5/24/21 2:04 PM, Waiman Long wrote: > On 5/24/21 3:47 PM, Randy Dunlap wrote: >> On 5/17/21 7:02 AM, Waiman Long wrote: >>> On 5/17/21 3:11 AM, Ingo Molnar wrote: >>>> * Randy Dunlap <rdunlap@infradead.org> wrote: >>>> >>>>> Both arch/um/ and arch/xtensa/ cause a Kconfig warning for LOCKDEP. >>>>> These arch-es select LOCKDEP_SUPPORT but they are not listed as one >>>>> of the arch-es that LOCKDEP depends on. >>>>> >>>>> Since (16) arch-es define the Kconfig symbol LOCKDEP_SUPPORT if they >>>>> intend to have LOCKDEP support, replace the awkward list of >>>>> arch-es that LOCKDEP depends on with the LOCKDEP_SUPPORT symbol. >>>>> >>>>> Fixes this kconfig warning: (for both um and xtensa) >>>>> >>>>> WARNING: unmet direct dependencies detected for LOCKDEP >>>>> Depends on [n]: DEBUG_KERNEL [=y] && LOCK_DEBUGGING_SUPPORT [=y] && (FRAME_POINTER [=n] || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86) >>>>> Selected by [y]: >>>>> - PROVE_LOCKING [=y] && DEBUG_KERNEL [=y] && LOCK_DEBUGGING_SUPPORT [=y] >>>>> - LOCK_STAT [=y] && DEBUG_KERNEL [=y] && LOCK_DEBUGGING_SUPPORT [=y] >>>>> - DEBUG_LOCK_ALLOC [=y] && DEBUG_KERNEL [=y] && LOCK_DEBUGGING_SUPPORT [=y] >>>>> >>>>> Signed-off-by: Randy Dunlap <rdunlap@infradead.org> >>>>> Cc: Peter Zijlstra <peterz@infradead.org> >>>>> Cc: Ingo Molnar <mingo@redhat.com> >>>>> Cc: Will Deacon <will@kernel.org> >>>>> Cc: Waiman Long <longman@redhat.com> >>>>> Cc: Boqun Feng <boqun.feng@gmail.com> >>>>> Cc: Chris Zankel <chris@zankel.net> >>>>> Cc: Max Filippov <jcmvbkbc@gmail.com> >>>>> Cc: linux-xtensa@linux-xtensa.org >>>>> Cc: Johannes Berg <johannes@sipsolutions.net> >>>>> Cc: Jeff Dike <jdike@addtoit.com> >>>>> Cc: Richard Weinberger <richard@nod.at> >>>>> Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com> >>>>> Cc: linux-um@lists.infradead.org >>>>> --- >>>>> lib/Kconfig.debug | 2 +- >>>>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>>> >>>>> --- linux-next-20210514.orig/lib/Kconfig.debug >>>>> +++ linux-next-20210514/lib/Kconfig.debug >>>>> @@ -1383,7 +1383,7 @@ config LOCKDEP >>>>> bool >>>>> depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT >>>>> select STACKTRACE >>>>> - depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86 >>>>> + depends on FRAME_POINTER || LOCKDEP_SUPPORT >>>> Ok - the FRAME_POINTER bit is weird. Are there any architectures that have >>>> FRAME_POINTER defined but no LOCKDEP_SUPPORT? >>> LOCK_DEBUGGING_SUPPORT depends on LOCKDEP_SUPPORT. So this patch is equivalent to just delete the second depends-on line. >> Yes, if we disregard the FRAME_POINTER part. > > My understanding is that the 2 depends-on statements have an implicit AND. So it is like Right (on the implicit AND). > DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT && (FRAME_POINTER || LOCKDEP_SUPPORT). LOCK_DEBUGGING_SUPPORT is true means the (FRAME_POINTER || LOCKDEP_SUPPORT) will always be true. FRAME_POINTER is true doesn't mean the other dependencies are true. That is why I said it is equivalent to just "DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT". IOW, FRAME_POINTER will play no part here. > Ack. I should have done that myself. >> >>> Beside LOCKDEP, LATENCYTOP also have exactly the same depends-on line. >> True, but I don't get any implication that the same patch applies there. >> Do you? > It is just an observation that I stumble on. It is not related to your patch. Got it. >>> So isn't FRAME_POINTER used mainly to support STACK_TRACE? However, LOCK_DEBUGGING_SUPPORT has already included STACK_TRACE_SUPPORT in its dependency. So why there is a FRAME_POINTER dependency? >> FRAME_POINTER is one way but it does not seem to be required >> for STACKTRACE_SUPPORT. >> >> Do you have any patch suggestions? > > Is it possible to just get rid of the 2nd depends-on statement? > > The 2nd depends-on line was introduced by commit 7d37cb2c912d ("lib: fix kconfig dependency on ARCH_WANT_FRAME_POINTER"): and I should have looked at that history too. Thanks. Yes, I agree, we can just delete that line... I'll send a v2 and copy the author of commit 7d37cb2c912d as well. > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug > index 2779c29d9981..417c3d3e521b 100644 > --- a/lib/Kconfig.debug > +++ b/lib/Kconfig.debug > @@ -1363,7 +1363,7 @@ config LOCKDEP > bool > depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT > select STACKTRACE > - select FRAME_POINTER if !MIPS && !PPC && !ARM && !S390 && !MICROBLAZE && > + depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || > select KALLSYMS > select KALLSYMS_ALL > > Since STACKTRACE is selected by lockdep, maybe we can just remove the 2nd depends-on line to see if anyone complain. > > Cheers, > Longman > thanks.
On 5/24/21 2:31 PM, Randy Dunlap wrote: > On 5/24/21 2:04 PM, Waiman Long wrote: >> On 5/24/21 3:47 PM, Randy Dunlap wrote: >>> On 5/17/21 7:02 AM, Waiman Long wrote: >>>> On 5/17/21 3:11 AM, Ingo Molnar wrote: >>>>> * Randy Dunlap <rdunlap@infradead.org> wrote: >>>>> >>>>>> Both arch/um/ and arch/xtensa/ cause a Kconfig warning for LOCKDEP. >>>>>> These arch-es select LOCKDEP_SUPPORT but they are not listed as one >>>>>> of the arch-es that LOCKDEP depends on. >>>>>> >>>>>> Since (16) arch-es define the Kconfig symbol LOCKDEP_SUPPORT if they >>>>>> intend to have LOCKDEP support, replace the awkward list of >>>>>> arch-es that LOCKDEP depends on with the LOCKDEP_SUPPORT symbol. >>>>>> >>>>>> Fixes this kconfig warning: (for both um and xtensa) >>>>>> >>>>>> WARNING: unmet direct dependencies detected for LOCKDEP >>>>>> Depends on [n]: DEBUG_KERNEL [=y] && LOCK_DEBUGGING_SUPPORT [=y] && (FRAME_POINTER [=n] || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86) >>>>>> Selected by [y]: >>>>>> - PROVE_LOCKING [=y] && DEBUG_KERNEL [=y] && LOCK_DEBUGGING_SUPPORT [=y] >>>>>> - LOCK_STAT [=y] && DEBUG_KERNEL [=y] && LOCK_DEBUGGING_SUPPORT [=y] >>>>>> - DEBUG_LOCK_ALLOC [=y] && DEBUG_KERNEL [=y] && LOCK_DEBUGGING_SUPPORT [=y] >>>>>> >>>>>> Signed-off-by: Randy Dunlap <rdunlap@infradead.org> >>>>>> Cc: Peter Zijlstra <peterz@infradead.org> >>>>>> Cc: Ingo Molnar <mingo@redhat.com> >>>>>> Cc: Will Deacon <will@kernel.org> >>>>>> Cc: Waiman Long <longman@redhat.com> >>>>>> Cc: Boqun Feng <boqun.feng@gmail.com> >>>>>> Cc: Chris Zankel <chris@zankel.net> >>>>>> Cc: Max Filippov <jcmvbkbc@gmail.com> >>>>>> Cc: linux-xtensa@linux-xtensa.org >>>>>> Cc: Johannes Berg <johannes@sipsolutions.net> >>>>>> Cc: Jeff Dike <jdike@addtoit.com> >>>>>> Cc: Richard Weinberger <richard@nod.at> >>>>>> Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com> >>>>>> Cc: linux-um@lists.infradead.org >>>>>> --- >>>>>> lib/Kconfig.debug | 2 +- >>>>>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>>>> >>>>>> --- linux-next-20210514.orig/lib/Kconfig.debug >>>>>> +++ linux-next-20210514/lib/Kconfig.debug >>>>>> @@ -1383,7 +1383,7 @@ config LOCKDEP >>>>>> bool >>>>>> depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT >>>>>> select STACKTRACE >>>>>> - depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86 >>>>>> + depends on FRAME_POINTER || LOCKDEP_SUPPORT >>>>> Ok - the FRAME_POINTER bit is weird. Are there any architectures that have >>>>> FRAME_POINTER defined but no LOCKDEP_SUPPORT? >>>> LOCK_DEBUGGING_SUPPORT depends on LOCKDEP_SUPPORT. So this patch is equivalent to just delete the second depends-on line. >>> Yes, if we disregard the FRAME_POINTER part. >> >> My understanding is that the 2 depends-on statements have an implicit AND. So it is like > > Right (on the implicit AND). > >> DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT && (FRAME_POINTER || LOCKDEP_SUPPORT). LOCK_DEBUGGING_SUPPORT is true means the (FRAME_POINTER || LOCKDEP_SUPPORT) will always be true. FRAME_POINTER is true doesn't mean the other dependencies are true. That is why I said it is equivalent to just "DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT". IOW, FRAME_POINTER will play no part here. >> > > Ack. I should have done that myself. > >>> >>>> Beside LOCKDEP, LATENCYTOP also have exactly the same depends-on line. >>> True, but I don't get any implication that the same patch applies there. >>> Do you? >> It is just an observation that I stumble on. It is not related to your patch. > > Got it. > >>>> So isn't FRAME_POINTER used mainly to support STACK_TRACE? However, LOCK_DEBUGGING_SUPPORT has already included STACK_TRACE_SUPPORT in its dependency. So why there is a FRAME_POINTER dependency? >>> FRAME_POINTER is one way but it does not seem to be required >>> for STACKTRACE_SUPPORT. >>> >>> Do you have any patch suggestions? >> >> Is it possible to just get rid of the 2nd depends-on statement? >> >> The 2nd depends-on line was introduced by commit 7d37cb2c912d ("lib: fix kconfig dependency on ARCH_WANT_FRAME_POINTER"): > > and I should have looked at that history too. Thanks. > > Yes, I agree, we can just delete that line... > > I'll send a v2 and copy the author of commit 7d37cb2c912d as well. Hm, as I review that commit, I have to wonder if the previous 'select' was correct (if we disregard the Kconfig warning). If so, then FRAME_POINTER is still wanted/needed for some arch-es. diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 2779c29d9981..417c3d3e521b 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -1363,7 +1363,7 @@ config LOCKDEP bool depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT select STACKTRACE - select FRAME_POINTER if !MIPS && !PPC && !ARM && !S390 && !MICROBLAZE && !ARC && !X86 <<<<<<<<<<< >> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug >> index 2779c29d9981..417c3d3e521b 100644 >> --- a/lib/Kconfig.debug >> +++ b/lib/Kconfig.debug >> @@ -1363,7 +1363,7 @@ config LOCKDEP >> bool >> depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT >> select STACKTRACE >> - select FRAME_POINTER if !MIPS && !PPC && !ARM && !S390 && !MICROBLAZE && >> + depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || >> select KALLSYMS >> select KALLSYMS_ALL >> >> Since STACKTRACE is selected by lockdep, maybe we can just remove the 2nd depends-on line to see if anyone complain.
On 5/24/21 5:41 PM, Randy Dunlap wrote: > On 5/24/21 2:31 PM, Randy Dunlap wrote: >> On 5/24/21 2:04 PM, Waiman Long wrote: >> >>> Is it possible to just get rid of the 2nd depends-on statement? >>> >>> The 2nd depends-on line was introduced by commit 7d37cb2c912d ("lib: fix kconfig dependency on ARCH_WANT_FRAME_POINTER"): >> and I should have looked at that history too. Thanks. >> >> Yes, I agree, we can just delete that line... >> >> I'll send a v2 and copy the author of commit 7d37cb2c912d as well. > Hm, as I review that commit, I have to wonder if the previous 'select' > was correct (if we disregard the Kconfig warning). If so, then > FRAME_POINTER is still wanted/needed for some arch-es. > > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug > index 2779c29d9981..417c3d3e521b 100644 > --- a/lib/Kconfig.debug > +++ b/lib/Kconfig.debug > @@ -1363,7 +1363,7 @@ config LOCKDEP > bool > depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT > select STACKTRACE > - select FRAME_POINTER if !MIPS && !PPC && !ARM && !S390 && !MICROBLAZE && !ARC && !X86 <<<<<<<<<<< > AFAICS, enabling FRAME_POINTER is a debugging aid as it enable more precise stacktrace. However, not all archs want to enable FRAME_POINTER because of LOCKDEP. Now you are just letting users decide if they want FRAME_POINTER or not. Maybe you can modify the help text to mention that. Cheers, Longman
On 5/24/21 5:05 PM, Waiman Long wrote: > On 5/24/21 5:41 PM, Randy Dunlap wrote: >> On 5/24/21 2:31 PM, Randy Dunlap wrote: >>> On 5/24/21 2:04 PM, Waiman Long wrote: >>> >>>> Is it possible to just get rid of the 2nd depends-on statement? >>>> >>>> The 2nd depends-on line was introduced by commit 7d37cb2c912d ("lib: fix kconfig dependency on ARCH_WANT_FRAME_POINTER"): >>> and I should have looked at that history too. Thanks. >>> >>> Yes, I agree, we can just delete that line... >>> >>> I'll send a v2 and copy the author of commit 7d37cb2c912d as well. >> Hm, as I review that commit, I have to wonder if the previous 'select' >> was correct (if we disregard the Kconfig warning). If so, then >> FRAME_POINTER is still wanted/needed for some arch-es. >> >> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug >> index 2779c29d9981..417c3d3e521b 100644 >> --- a/lib/Kconfig.debug >> +++ b/lib/Kconfig.debug >> @@ -1363,7 +1363,7 @@ config LOCKDEP >> bool >> depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT >> select STACKTRACE >> - select FRAME_POINTER if !MIPS && !PPC && !ARM && !S390 && !MICROBLAZE && !ARC && !X86 <<<<<<<<<<< >> > AFAICS, enabling FRAME_POINTER is a debugging aid as it enable more precise stacktrace. However, not all archs want to enable FRAME_POINTER because of LOCKDEP. Now you are just letting users decide if they want FRAME_POINTER or not. Maybe you can modify the help text to mention that. LOCKDEP doesn't have any user help text. For FRAME_POINTER, when ARCH_WANT_FRAME_POINTERS + a few other conditions is met, it seems that the FRAME_POINTER help text is good enough IMO. help If you say Y here the resulting kernel image will be slightly larger and slower, but it gives very useful debugging information in case of kernel bugs. (precise oopses/stacktraces/warnings)
On 5/25/21 12:18 AM, Randy Dunlap wrote: > On 5/24/21 5:05 PM, Waiman Long wrote: >> On 5/24/21 5:41 PM, Randy Dunlap wrote: >>> On 5/24/21 2:31 PM, Randy Dunlap wrote: >>>> On 5/24/21 2:04 PM, Waiman Long wrote: >>>> >>>>> Is it possible to just get rid of the 2nd depends-on statement? >>>>> >>>>> The 2nd depends-on line was introduced by commit 7d37cb2c912d ("lib: fix kconfig dependency on ARCH_WANT_FRAME_POINTER"): >>>> and I should have looked at that history too. Thanks. >>>> >>>> Yes, I agree, we can just delete that line... >>>> >>>> I'll send a v2 and copy the author of commit 7d37cb2c912d as well. >>> Hm, as I review that commit, I have to wonder if the previous 'select' >>> was correct (if we disregard the Kconfig warning). If so, then >>> FRAME_POINTER is still wanted/needed for some arch-es. >>> >>> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug >>> index 2779c29d9981..417c3d3e521b 100644 >>> --- a/lib/Kconfig.debug >>> +++ b/lib/Kconfig.debug >>> @@ -1363,7 +1363,7 @@ config LOCKDEP >>> bool >>> depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT >>> select STACKTRACE >>> - select FRAME_POINTER if !MIPS && !PPC && !ARM && !S390 && !MICROBLAZE && !ARC && !X86 <<<<<<<<<<< >>> >> AFAICS, enabling FRAME_POINTER is a debugging aid as it enable more precise stacktrace. However, not all archs want to enable FRAME_POINTER because of LOCKDEP. Now you are just letting users decide if they want FRAME_POINTER or not. Maybe you can modify the help text to mention that. > LOCKDEP doesn't have any user help text. > > For FRAME_POINTER, when ARCH_WANT_FRAME_POINTERS + a few other conditions > is met, it seems that the FRAME_POINTER help text is good enough IMO. > > help > If you say Y here the resulting kernel image will be slightly > larger and slower, but it gives very useful debugging information > in case of kernel bugs. (precise oopses/stacktraces/warnings) > Right. I am fine with that. Thanks, Longman
--- linux-next-20210514.orig/lib/Kconfig.debug +++ linux-next-20210514/lib/Kconfig.debug @@ -1383,7 +1383,7 @@ config LOCKDEP bool depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT select STACKTRACE - depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86 + depends on FRAME_POINTER || LOCKDEP_SUPPORT select KALLSYMS select KALLSYMS_ALL
Both arch/um/ and arch/xtensa/ cause a Kconfig warning for LOCKDEP. These arch-es select LOCKDEP_SUPPORT but they are not listed as one of the arch-es that LOCKDEP depends on. Since (16) arch-es define the Kconfig symbol LOCKDEP_SUPPORT if they intend to have LOCKDEP support, replace the awkward list of arch-es that LOCKDEP depends on with the LOCKDEP_SUPPORT symbol. Fixes this kconfig warning: (for both um and xtensa) WARNING: unmet direct dependencies detected for LOCKDEP Depends on [n]: DEBUG_KERNEL [=y] && LOCK_DEBUGGING_SUPPORT [=y] && (FRAME_POINTER [=n] || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86) Selected by [y]: - PROVE_LOCKING [=y] && DEBUG_KERNEL [=y] && LOCK_DEBUGGING_SUPPORT [=y] - LOCK_STAT [=y] && DEBUG_KERNEL [=y] && LOCK_DEBUGGING_SUPPORT [=y] - DEBUG_LOCK_ALLOC [=y] && DEBUG_KERNEL [=y] && LOCK_DEBUGGING_SUPPORT [=y] Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Will Deacon <will@kernel.org> Cc: Waiman Long <longman@redhat.com> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Chris Zankel <chris@zankel.net> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: linux-xtensa@linux-xtensa.org Cc: Johannes Berg <johannes@sipsolutions.net> Cc: Jeff Dike <jdike@addtoit.com> Cc: Richard Weinberger <richard@nod.at> Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com> Cc: linux-um@lists.infradead.org --- lib/Kconfig.debug | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)