From mboxrd@z Thu Jan 1 00:00:00 1970 From: Qian Cai Date: Tue, 15 Oct 2019 18:42:00 +0000 Subject: Re: [PATCH V6 0/2] mm/debug: Add tests validating architecture page table helpers Message-Id: <1571164920.5937.45.camel@lca.pw> List-Id: References: <1571131302-32290-1-git-send-email-anshuman.khandual@arm.com> <1571150502.5937.39.camel@lca.pw> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit To: Anshuman Khandual , linux-mm@kvack.org Cc: Mark Rutland , linux-ia64@vger.kernel.org, linux-sh@vger.kernel.org, Peter Zijlstra , James Hogan , Heiko Carstens , Michal Hocko , Dave Hansen , Paul Mackerras , sparclinux@vger.kernel.org, Thomas Gleixner , linux-s390@vger.kernel.org, Jason Gunthorpe , Michael Ellerman , x86@kernel.org, Russell King - ARM Linux , Matthew Wilcox , Steven Price , Tetsuo Handa , Gerald Schaefer , linux-snps-arc@lists.infradead.org, linux-arm-kernel@lists.infradead.org, Kees Cook , Masahiro Yamada , Mark Brown , "Kirill A . Shutemov" , Dan Williams , Vlastimil Babka , Christophe Leroy , Sri Krishna chowdary , Ard Biesheuvel , Greg Kroah-Hartman , linux-mips@vger.kernel.org, Ralf Baechle , linux-kernel@vger.kernel.org, Paul Burton , Mike Rapoport , Vineet Gupta , Martin Schwidefsky , Andrew Morton , linuxppc-dev@lists.ozlabs.org, "David S. Miller" , Mike Kravetz On Tue, 2019-10-15 at 20:51 +0530, Anshuman Khandual wrote: > > On 10/15/2019 08:11 PM, Qian Cai wrote: > > The x86 will crash with linux-next during boot due to this series (v5) with the > > config below plus CONFIG_DEBUG_VM_PGTABLE=y. I am not sure if v6 would address > > it. > > > > https://raw.githubusercontent.com/cailca/linux-mm/master/x86.config > > > > [   33.862600][    T1] page:ffffea0009000000 is uninitialized and poisoned > > [   33.862608][    T1] raw: ffffffffffffffff ffffffffffffffff ffffffffffffffff > > ffffff871140][    T1]  ? _raw_spin_unlock_irq+0x27/0x40 > > [   33.871140][    T1]  ? rest_init+0x307/0x307 > > [   33.871140][    T1]  kernel_init+0x11/0x139 > > [   33.871140][    T1]  ? rest_init+0x307/0x307 > > [   33.871140][    T1]  ret_from_fork+0x27/0x50 > > [   33.871140][    T1] Modules linked in: > > [   33.871140][    T1] ---[ end trace e99d392b0f7befbd ]--- > > [   33.871140][    T1] RIP: 0010:alloc_gigantic_page_order+0x3fe/0x490 > > Hmm, with defconfig (DEBUG_VM=y and DEBUG_VM_PGTABLE=y) it does not crash but > with the config above, it does. Just wondering if it is possible that these > pages might not been initialized yet because DEFERRED_STRUCT_PAGE_INIT=y ? Yes, this patch works fine. diff --git a/init/main.c b/init/main.c index 676d8020dd29..591be8f9e8e0 100644 --- a/init/main.c +++ b/init/main.c @@ -1177,7 +1177,6 @@ static noinline void __init kernel_init_freeable(void)         workqueue_init();           init_mm_internals(); -       debug_vm_pgtable();           do_pre_smp_initcalls();         lockup_detector_init(); @@ -1186,6 +1185,8 @@ static noinline void __init kernel_init_freeable(void)         sched_init_smp();           page_alloc_init_late(); +       debug_vm_pgtable(); +         /* Initialize page ext after all struct pages are initialized. */         page_ext_init(); > > [ 13.898549][ T1] page:ffffea0005000000 is uninitialized and poisoned > [ 13.898549][ T1] raw: ffffffffffffffff ffffffffffffffff ffffffffffffffff ffffffffffffffff > [ 13.898549][ T1] raw: ffffffffffffffff ffffffffffffffff ffffffffffffffff ffffffffffffffff > [ 13.898549][ T1] page dumped because: VM_BUG_ON_PAGE(PagePoisoned(p)) > [ 13.898549][ T1] ------------[ cut here ]------------ > [ 13.898549][ T1] kernel BUG at ./include/linux/mm.h:1107! > [ 13.898549][ T1] invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN PTI > [ 13.898549][ T1] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.4.0-rc3-next-20191015+ #