Messages in this thread | | | Subject | Re: [LKP] Re: [mm/debug] fa6726c1e7: kernel_BUG_at_include/linux/mm.h | From | Christophe Leroy <> | Date | Wed, 29 Apr 2020 20:34:17 +0200 |
| |
Le 29/04/2020 à 20:15, Catalin Marinas a écrit : > On Wed, Apr 29, 2020 at 08:52:25PM +0800, Chen, Rong A wrote: >> On 4/29/2020 11:28 AM, Anshuman Khandual wrote: >>> On 04/28/2020 02:51 PM, Catalin Marinas wrote: >>>> On Tue, Apr 28, 2020 at 04:41:11AM -0400, Qian Cai wrote: >>>>> On Apr 28, 2020, at 1:54 AM, Anshuman Khandual <Anshuman.Khandual@arm.com> wrote: >>>>>> That is true. There is a slight change in the rules, making it explicit yes >>>>>> only when both ARCH_HAS_DEBUG_VM_PGTABLE and DEBUG_VM are enabled. >>>>>> >>>>>> +config DEBUG_VM_PGTABLE >>>>>> + bool "Debug arch page table for semantics compliance" >>>>>> + depends on MMU >>>>>> + depends on !IA64 && !ARM >>>>>> + depends on ARCH_HAS_DEBUG_VM_PGTABLE || EXPERT >>>>>> + default y if ARCH_HAS_DEBUG_VM_PGTABLE && DEBUG_VM >>>>>> + help >>>>>> >>>>>> The default is really irrelevant as the config option can be set explicitly. >>>>> That could also explain. Since not long time ago, it was only “default >>>>> y if DEBUG_VM”, that caused the robot saved a .config with >>>>> DEBUG_VM_PGTABLE=y by default. >>>>> >>>>> Even though you changed the rule recently, it has no effect as the >>>>> robot could “make oldconfig” from the saved config for each linux-next >>>>> tree execution and the breakage will go on. >>>> I'm not entirely sure that's the case. This report still points at the >>>> old commit fa6726c1e7 which has: >>>> >>>> + depends on ARCH_HAS_DEBUG_VM_PGTABLE || EXPERT >>>> + default n if !ARCH_HAS_DEBUG_VM_PGTABLE >>>> + default y if DEBUG_VM >>>> >>>> In -next we now have commit 647d9a0de34c and subsequently modified by >>>> commit 0a8646638865. So hopefully with the latest -next tree we won't >>>> see this report. >>> Could some one from LKP test framework, please confirm if this still causes >>> above problem on the latest linux-next by default ? >> >> The .config is a rand config, the problem is still exist if run "make >> oldconfig" for the config with commit 0a8646638865. > > Is randconfig expected to boot? I don't think it is but I guess it > should not trigger a BUG_ON during boot. > >> $ grep -e CONFIG_MMU= -e CONFIG_EXPERT= -e CONFIG_ARCH_HAS_DEBUG_VM_PGTABLE= >> -e CONFIG_DEBUG_VM= .config >> CONFIG_EXPERT=y >> CONFIG_MMU=y >> CONFIG_DEBUG_VM=y >> >> should we disable DEBUG_VM_PGTABLE by default? > > If that's the only case where this fails in LKP, I'd rather remove the > EXPERT dependency so that it cannot be enabled. Architectures that want > to experiment with this feature will have to select > ARCH_HAS_DEBUG_VM_PGTABLE explicitly. >
But when something is not selectable, people won't even know it exists.
Why not try and fix the problems reported by the robots instead ?
| |