From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michal Hocko Date: Wed, 16 Oct 2019 08:20:22 +0000 Subject: Re: [PATCH V6 0/2] mm/debug: Add tests validating architecture page table helpers Message-Id: <20191016082022.GN317@dhcp22.suse.cz> 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="iso-8859-1" Content-Transfer-Encoding: quoted-printable To: Anshuman Khandual Cc: Mark Rutland , linux-ia64@vger.kernel.org, linux-sh@vger.kernel.org, Peter Zijlstra , James Hogan , Tetsuo Handa , Heiko Carstens , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Dave Hansen , Paul Mackerras , sparclinux@vger.kernel.org, Thomas Gleixner , linux-s390@vger.kernel.org, Michael Ellerman , x86@kernel.org, Russell King - ARM Linux , Matthew Wilcox , Steven Price , Jason Gunthorpe , Gerald Schaefer , linux-snps-arc@lists.infradead.org, linux-arm-kernel@lists.infradead.org, Kees Cook , Masahiro Yamada , Mark Brown , Qian Cai , "Kirill A . Shutemov" , Dan Williams , Vlastimil Babka , Christophe Leroy , Sri Krishna chowdary , Ard Biesheuvel , Greg Kroah-Hartman , linux-mips@vger.kernel.org, Ralf Baechle , Paul Burton , Mike Rapoport , Vineet Gupta , Martin Schwidefsky , Andrew Morton , linuxppc-dev@lists.ozlabs.org, "David S. Miller" , Mike Kravetz On Tue 15-10-19 20:51:11, Anshuman Khandual wrote: >=20 >=20 > 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=3Dy. I am not sure if v6 woul= d address > > it. > >=20 > > https://raw.githubusercontent.com/cailca/linux-mm/master/x86.config > >=20 > > [=A0=A0=A033.862600][=A0=A0=A0=A0T1] page:ffffea0009000000 is uninitial= ized and poisoned > > [=A0=A0=A033.862608][=A0=A0=A0=A0T1] raw: ffffffffffffffff ffffffffffff= ffff ffffffffffffffff > > ffffff871140][=A0=A0=A0=A0T1]=A0=A0? _raw_spin_unlock_irq+0x27/0x40 > > [=A0=A0=A033.871140][=A0=A0=A0=A0T1]=A0=A0? rest_init+0x307/0x307 > > [=A0=A0=A033.871140][=A0=A0=A0=A0T1]=A0=A0kernel_init+0x11/0x139 > > [=A0=A0=A033.871140][=A0=A0=A0=A0T1]=A0=A0? rest_init+0x307/0x307 > > [=A0=A0=A033.871140][=A0=A0=A0=A0T1]=A0=A0ret_from_fork+0x27/0x50 > > [=A0=A0=A033.871140][=A0=A0=A0=A0T1] Modules linked in: > > [=A0=A0=A033.871140][=A0=A0=A0=A0T1] ---[ end trace e99d392b0f7befbd ]-= -- > > [=A0=A0=A033.871140][=A0=A0=A0=A0T1] RIP: 0010:alloc_gigantic_page_orde= r+0x3fe/0x490 >=20 > Hmm, with defconfig (DEBUG_VM=3Dy and DEBUG_VM_PGTABLE=3Dy) it does not c= rash but > with the config above, it does. Just wondering if it is possible that the= se > pages might not been initialized yet because DEFERRED_STRUCT_PAGE_INIT=3D= y ? Quite likely. You need to wait for page_alloc_init_late to finish. >=20 > [ 13.898549][ T1] page:ffffea0005000000 is uninitialized and poisoned > [ 13.898549][ T1] raw: ffffffffffffffff ffffffffffffffff fffffffffff= fffff ffffffffffffffff > [ 13.898549][ T1] raw: ffffffffffffffff ffffffffffffffff fffffffffff= fffff 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 KASA= N PTI > [ 13.898549][ T1] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.4.0-rc= 3-next-20191015+ # --=20 Michal Hocko SUSE Labs