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Received: from DESKTOP-5N7EMDA(mailfrom:ying.huang@linux.alibaba.com fp:SMTPD_---0X1i.oX8_1777254163 cluster:ay36) by smtp.aliyun-inc.com; Mon, 27 Apr 2026 09:42:57 +0800 From: "Huang, Ying" To: Sunny Patel Cc: Andrew Morton , David Hildenbrand , Zi Yan , Matthew Brost , Joshua Hahn , Rakie Kim , Byungchul Park , Gregory Price , Alistair Popple , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm/migrate_device: fix pgtable leak in migrate_vma_insert_huge_pmd_page In-Reply-To: <20260425134453.23769-1-nueralspacetech@gmail.com> (Sunny Patel's message of "Sat, 25 Apr 2026 19:14:48 +0530") References: <20260425134453.23769-1-nueralspacetech@gmail.com> Date: Mon, 27 Apr 2026 09:42:42 +0800 Message-ID: <87fr4hw54d.fsf@DESKTOP-5N7EMDA> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain; charset=ascii X-Rspam-User: X-Rspamd-Queue-Id: E0D1DA0002 X-Rspamd-Server: rspam06 X-Stat-Signature: tjx1iyqgg1rytyo3wqncjz8anynoq7bc X-HE-Tag: 1777254181-964806 X-HE-Meta: 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 G0W9aXuV slur55vjfrbs0+tUen9sMaP1brSu3B6VmPAQYz2qW4pqlAIac42cJ4Pf9ys52WPWWJId4LvdVT0tWamxHTiHDznKU7og8O8DRfA+WOnbj6DDXFBqCAIgHRcuP6T+X/2XX0rsyoiCJf+npqIOv3xoH/kskCK+FYS5pLwyw2mIIxtlfdDlogbiLJNUc+mHh5QQrzrHgnMR4TvJJHTGrHIKOwD7n8RwD1e5qub8ZIY7uaoXa/vyIy1DHodxQg5Z39YXDLB+E8sbSoJIINZSD1j+BnMTmxJJHrooWYF5qzucKzMUjl/b6fOiNxJB69kxe3pmp1ASWNhWAeLiOius3A4IWCcooXrb4RfKRSnP4nzNWv9Y0dnrhjPq9dBwD847IZ0yKQFQ/nqHa6xKwoJI9d5gTHWnIev1f1mq+BDFF Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Hi, Sunny, Thanks for working on this! Sunny Patel writes: > When migrate_vma_insert_huge_pmd_page() jumps to unlock_abort due > to a PMD check failure, the pgtable allocated earlier via > pte_alloc_one() is never freed, causing a memory leak. > > Add a pte_free() call in the unlock_abort error path to release > the pgtable before returning. > > Signed-off-by: Sunny Patel > --- > mm/migrate_device.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/mm/migrate_device.c b/mm/migrate_device.c > index fbfe5715f635..457bab5c7c31 100644 > --- a/mm/migrate_device.c > +++ b/mm/migrate_device.c > @@ -893,6 +893,7 @@ static int migrate_vma_insert_huge_pmd_page(struct migrate_vma *migrate, > > unlock_abort: > spin_unlock(ptl); > + pte_free(vma->vm_mm, pgtable); > abort: > for (i = 0; i < HPAGE_PMD_NR; i++) > src[i] &= ~MIGRATE_PFN_MIGRATE; Is it better to use guard based automatic memory freeing? And check whether guard can help unlock case too? --- Best Regards, Huang, Ying