From mboxrd@z Thu Jan 1 00:00:00 1970 From: Baolin Wang Date: Tue, 10 May 2022 04:26:32 +0000 Subject: Re: [PATCH v3 0/3] Fix CONT-PTE/PMD size hugetlb issue when unmapping or migrating Message-Id: <0db300f4-8a91-b330-5c6f-bbc63cf2f151@linux.alibaba.com> List-Id: References: <20220509210404.6a43aff15d0d6b3af0741001@linux-foundation.org> In-Reply-To: <20220509210404.6a43aff15d0d6b3af0741001@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Andrew Morton Cc: mike.kravetz@oracle.com, catalin.marinas@arm.com, will@kernel.org, songmuchun@bytedance.com, tsbogend@alpha.franken.de, James.Bottomley@HansenPartnership.com, deller@gmx.de, mpe@ellerman.id.au, benh@kernel.crashing.org, paulus@samba.org, hca@linux.ibm.com, gor@linux.ibm.com, agordeev@linux.ibm.com, borntraeger@linux.ibm.com, svens@linux.ibm.com, ysato@users.osdn.me, dalias@libc.org, davem@davemloft.net, arnd@arndb.de, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org On 5/10/2022 12:04 PM, Andrew Morton wrote: > On Tue, 10 May 2022 11:45:57 +0800 Baolin Wang wrote: > >> Hi, >> >> Now migrating a hugetlb page or unmapping a poisoned hugetlb page, we'll >> use ptep_clear_flush() and set_pte_at() to nuke the page table entry >> and remap it, and this is incorrect for CONT-PTE or CONT-PMD size hugetlb >> page, > > It would be helpful to describe why it's wrong. Something like "should > use huge_ptep_clear_flush() and huge_ptep_clear_flush() for this > purpose"? Sorry for the confusing description. I described the problem explicitly in each patch's commit message. https://lore.kernel.org/all/ea5abf529f0997b5430961012bfda6166c1efc8c.1652147571.git.baolin.wang@linux.alibaba.com/ https://lore.kernel.org/all/730ea4b6d292f32fb10b7a4e87dad49b0eb30474.1652147571.git.baolin.wang@linux.alibaba.com/ > >> which will cause potential data consistent issue. This patch set >> will change to use hugetlb related APIs to fix this issue, please find >> details in each patch. Thanks. > > Is a cc:stable needed here? And are we able to identify a target for a > Fixes: tag? I think need a cc:stable tag, however I am not sure the target fixes tag, since we should trace back to the introduction of CONT-PTE/PMD hugetlb? 66b3923a1a0f ("arm64: hugetlb: add support for PTE contiguous bit")