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Tue, 25 Jan 2022 22:27:00 -0800 (PST) Date: Tue, 25 Jan 2022 22:26:59 -0800 (PST) From: David Rientjes To: Pasha Tatashin cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, akpm@linux-foundation.org, pjt@google.com, weixugc@google.com, gthelen@google.com, mingo@redhat.com, will@kernel.org, rppt@kernel.org, dave.hansen@linux.intel.com, hpa@zytor.com, aneesh.kumar@linux.ibm.com, jirislaby@kernel.org, songmuchun@bytedance.com, qydwhotmail@gmail.com, hughd@google.com, ziy@nvidia.com, anshuman.khandual@arm.com Subject: Re: [PATCH v3 1/4] mm/debug_vm_pgtable: remove pte entry from the page table In-Reply-To: <20220126060514.1574935-2-pasha.tatashin@soleen.com> Message-ID: <6e7a364-f252-9622-38c0-d0b7541f87a4@google.com> References: <20220126060514.1574935-1-pasha.tatashin@soleen.com> <20220126060514.1574935-2-pasha.tatashin@soleen.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Stat-Signature: hryx5gud313aqibacqfed3oouch34xq4 X-Rspam-User: nil Authentication-Results: imf06.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=FBhdu+gT; spf=pass (imf06.hostedemail.com: domain of rientjes@google.com designates 209.85.214.176 as permitted sender) smtp.mailfrom=rientjes@google.com; dmarc=pass (policy=reject) header.from=google.com X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 720A0180003 X-HE-Tag: 1643178422-136230 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, 26 Jan 2022, Pasha Tatashin wrote: > The pte entry that is used in pte_advanced_tests() is never removed from > the page table at the end of the test. > > The issue is detected by page_table_check, to repro compile kernel with > the following configs: > > CONFIG_DEBUG_VM_PGTABLE=y > CONFIG_PAGE_TABLE_CHECK=y > CONFIG_PAGE_TABLE_CHECK_ENFORCED=y > > During the boot the following BUG is printed: > > [ 2.262821] debug_vm_pgtable: [debug_vm_pgtable ]: Validating > architecture page table helpers > [ 2.276826] ------------[ cut here ]------------ > [ 2.280426] kernel BUG at mm/page_table_check.c:162! > [ 2.284118] invalid opcode: 0000 [#1] PREEMPT SMP PTI > [ 2.287787] CPU: 0 PID: 1 Comm: swapper/0 Not tainted > 5.16.0-11413-g2c271fe77d52 #3 > [ 2.293226] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), > BIOS rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org > 04/01/2014 > ... > > The entry should be properly removed from the page table before the page > is released to the free list. > > Fixes: a5c3b9ffb0f4 ("mm/debug_vm_pgtable: add tests validating advanced arch page table helpers") > > Signed-off-by: Pasha Tatashin > Reviewed-by: Zi Yan > Tested-by: Zi Yan Acked-by: David Rientjes I think we also likely want: Cc: stable@vger.kernel.org # 5.9+