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[70.31.27.79]) by smtp.gmail.com with ESMTPSA id u7-20020a05620a430700b006eed75805a2sm1491342qko.126.2022.11.17.17.10.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 17 Nov 2022 17:10:41 -0800 (PST) From: Peter Xu To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Rik van Riel , Muchun Song , Andrew Morton , peterx@redhat.com, James Houghton , Nadav Amit , Andrea Arcangeli , David Hildenbrand , Miaohe Lin , Mike Kravetz Subject: [PATCH RFC v2 09/12] mm/hugetlb: Use hugetlb walker lock in hugetlb_vma_maps_page() Date: Thu, 17 Nov 2022 20:10:22 -0500 Message-Id: <20221118011025.2178986-10-peterx@redhat.com> X-Mailer: git-send-email 2.37.3 In-Reply-To: <20221118011025.2178986-1-peterx@redhat.com> References: <20221118011025.2178986-1-peterx@redhat.com> MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-type: text/plain ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1668733845; a=rsa-sha256; cv=none; b=pIpm7NTjERExPH16U3/SaqPMROS/o8itCR8OXxrVLf6XOJxMMKJzzy+A+16QWkOPz9dM7Y siUa49WBHFjppD62O4cN7dK7V8/cPDP7f1IJ+C5/LuS/PU0hSWeoDW4Q8hVOwxipLCYnID QjotQplytLj0IwSo0ntYW/Mlzjp0bJY= ARC-Authentication-Results: i=1; imf06.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=P1IX7psO; dmarc=pass (policy=none) header.from=redhat.com; spf=pass (imf06.hostedemail.com: domain of peterx@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=peterx@redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1668733845; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=ap7neQhploF5O2byy6eWIJyWsli20vMRANWIX9Kzu5I=; b=TVkuGywXH1MVttN86XmsbONXzdaqIPIrqNCWKs8rQdBjajjU2SF7VTzxp4DydEb+qcok+F DQmd+NDQf1r90SV08g8aKD4v9WLKs2k4xPap0zytv72ch0h0dqehKOuNGRgHGT+3emXOEr KxEezkC8bLOKAi9aPKDveTKhhJ9zrCk= Authentication-Results: imf06.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=P1IX7psO; dmarc=pass (policy=none) header.from=redhat.com; spf=pass (imf06.hostedemail.com: domain of peterx@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=peterx@redhat.com X-Rspam-User: X-Stat-Signature: qnwb8omo3mgciu4n5oozryzh7m8mg5pd X-Rspamd-Queue-Id: E84D0180003 X-Rspamd-Server: rspam11 X-HE-Tag: 1668733844-118745 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: Hugetlb walker lock makes sure the pte_t* won't go away from under us. Signed-off-by: Peter Xu --- fs/hugetlbfs/inode.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c index fdb16246f46e..265508981ba1 100644 --- a/fs/hugetlbfs/inode.c +++ b/fs/hugetlbfs/inode.c @@ -387,21 +387,24 @@ static bool hugetlb_vma_maps_page(struct vm_area_struct *vma, unsigned long addr, struct page *page) { pte_t *ptep, pte; + bool result = false; + hugetlb_walker_lock(); ptep = huge_pte_offset(vma->vm_mm, addr, huge_page_size(hstate_vma(vma))); if (!ptep) - return false; + goto out; pte = huge_ptep_get(ptep); if (huge_pte_none(pte) || !pte_present(pte)) - return false; + goto out; if (pte_page(pte) == page) - return true; - - return false; + result = true; +out: + hugetlb_walker_unlock(); + return result; } /*