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GET /api/patches/2216639/?format=api
{ "id": 2216639, "url": "http://patchwork.ozlabs.org/api/patches/2216639/?format=api", "web_url": "http://patchwork.ozlabs.org/project/linuxppc-dev/patch/20260327021403.214713-7-usama.arif@linux.dev/", "project": { "id": 2, "url": "http://patchwork.ozlabs.org/api/projects/2/?format=api", "name": "Linux PPC development", "link_name": "linuxppc-dev", "list_id": "linuxppc-dev.lists.ozlabs.org", "list_email": "linuxppc-dev@lists.ozlabs.org", "web_url": "https://github.com/linuxppc/wiki/wiki", "scm_url": "https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git", "webscm_url": "https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/", "list_archive_url": "https://lore.kernel.org/linuxppc-dev/", "list_archive_url_format": "https://lore.kernel.org/linuxppc-dev/{}/", "commit_url_format": "https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/commit/?id={}" }, "msgid": "<20260327021403.214713-7-usama.arif@linux.dev>", "list_archive_url": "https://lore.kernel.org/linuxppc-dev/20260327021403.214713-7-usama.arif@linux.dev/", "date": "2026-03-27T02:08:48", "name": "[v3,06/24] mm: thp: handle split failure in wp_huge_pmd()", "commit_ref": null, "pull_url": null, "state": "handled-elsewhere", "archived": false, "hash": "55f3f700fdcf0db454292a5ce345c0246f3bbbcb", "submitter": { "id": 92719, "url": "http://patchwork.ozlabs.org/api/people/92719/?format=api", "name": "Usama Arif", "email": "usama.arif@linux.dev" }, "delegate": null, "mbox": "http://patchwork.ozlabs.org/project/linuxppc-dev/patch/20260327021403.214713-7-usama.arif@linux.dev/mbox/", "series": [ { "id": 497678, "url": "http://patchwork.ozlabs.org/api/series/497678/?format=api", "web_url": "http://patchwork.ozlabs.org/project/linuxppc-dev/list/?series=497678", "date": "2026-03-27T02:08:43", "name": "[v3,01/24] mm: thp: make split_huge_pmd functions return int for error propagation", "version": 3, "mbox": "http://patchwork.ozlabs.org/series/497678/mbox/" } ], "comments": "http://patchwork.ozlabs.org/api/patches/2216639/comments/", "check": "pending", "checks": "http://patchwork.ozlabs.org/api/patches/2216639/checks/", "tags": {}, "related": [], "headers": { "Return-Path": "\n <linuxppc-dev+bounces-18849-incoming=patchwork.ozlabs.org@lists.ozlabs.org>", "X-Original-To": [ "incoming@patchwork.ozlabs.org", "linuxppc-dev@lists.ozlabs.org" ], "Delivered-To": "patchwork-incoming@legolas.ozlabs.org", "Authentication-Results": [ "legolas.ozlabs.org;\n\tdkim=pass (1024-bit key;\n unprotected) header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256\n header.s=key1 header.b=qCDvFHls;\n\tdkim-atps=neutral", "legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=lists.ozlabs.org\n (client-ip=2404:9400:21b9:f100::1; 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Fri, 27 Mar 2026 13:15:07 +1100 (AEDT)" ], "ARC-Seal": "i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1774577708;\n\tcv=none;\n b=d9mm4lvjPTercly7TPrwtOH+IGUJWTueYIg6oF8ZIUNwZdAZqtFc4nzBFOi2LS3lqXTHDimjz+DpTBBk+wbqg51QlT7IYx1mzvGB/ekHcWxIZm1IvLOhU6+wVly/GRWdFlJTlpx0vx/3RvyBJkBaXMI9xtelhrrXG0BinMsnIER9kEpOWtXRQ34Nb20mHld7+hj4DJSUztbYuLwNw/ju3nkR+Y+NgIKNqctDD7URkh1i9AE8zAxCYEe+XN9pneNNCoIabcnqmMCVAZJ+pJvZEXbt1+yqC+chgqw0BWEiPzGRrq1D9hyv+j1V59Bue9DoQJxAxYAOTBUn7BFqXYgcnw==", "ARC-Message-Signature": "i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707;\n\tt=1774577708; c=relaxed/relaxed;\n\tbh=aCI7ssiILkMHWnNEWRqeaTC8kADA5FVp8TNFAvIRw20=;\n\th=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References:\n\t MIME-Version;\n b=Og7GPQb2SB/NsZyR6y/NVESx8St+D23rAmkYUEfHnEzQLuiOoYubX5GGfvEwiFZTF8PAoAZdgbakUMkOZ/gNIc6Liaj3y3ZgcrhuHGXYwpXD7bFxeTwdDFA8MbzJbQpvGiACSTnSQAr84gnHLRcww/RNlMm9BNpGWGGhJIjTvoUxWa56vxFgOUZFoA6Z9vyGg4ud8se67bSqRuw2GXkv48uCwtmToM2Temm7ql4m+/AB+OuaRlYsYqX+PSIF/6o+dCOmK5N/hBWfUBjy1x5DOONkV3zEl8fvewPALMLMDkkaF2MNvmT7OC6/5g90Dwt5aTplRGcK0hx+AwkLl6+xbw==", "ARC-Authentication-Results": "i=1; lists.ozlabs.org;\n dmarc=pass (p=none dis=none) header.from=linux.dev; dkim=pass (1024-bit key;\n unprotected) header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256\n header.s=key1 header.b=qCDvFHls; dkim-atps=neutral;\n spf=pass (client-ip=95.215.58.181; helo=out-181.mta1.migadu.com;\n envelope-from=usama.arif@linux.dev;\n receiver=lists.ozlabs.org) smtp.mailfrom=linux.dev", "X-Report-Abuse": "Please report any abuse attempt to abuse@migadu.com and\n include these headers.", "DKIM-Signature": "v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1;\n\tt=1774577688;\n\th=from:from:reply-to:subject:subject:date:date:message-id:message-id:\n\t to:to:cc:cc:mime-version:mime-version:\n\t content-transfer-encoding:content-transfer-encoding:\n\t in-reply-to:in-reply-to:references:references;\n\tbh=aCI7ssiILkMHWnNEWRqeaTC8kADA5FVp8TNFAvIRw20=;\n\tb=qCDvFHlsrwn4BvHyl/OogfK+SU4PjAk/orshzs5oMnmbbYqMdO8VxcJG7SBrE5JnvZqhvW\n\tkHDxMSY4i21WqlUHUenbjsbHJeQSPwrgThPtMRU39TVbMcqqZ2CIv39avji+vUki/1rSj8\n\tMrVPi7UsYpHW/i7zFvcn0mt99gsGNQA=", "From": "Usama Arif <usama.arif@linux.dev>", "To": "Andrew Morton <akpm@linux-foundation.org>,\n\tdavid@kernel.org,\n\tLorenzo Stoakes <ljs@kernel.org>,\n\twilly@infradead.org,\n\tlinux-mm@kvack.org", "Cc": "fvdl@google.com,\n\thannes@cmpxchg.org,\n\triel@surriel.com,\n\tshakeel.butt@linux.dev,\n\tkas@kernel.org,\n\tbaohua@kernel.org,\n\tdev.jain@arm.com,\n\tbaolin.wang@linux.alibaba.com,\n\tnpache@redhat.com,\n\tLiam.Howlett@oracle.com,\n\tryan.roberts@arm.com,\n\tVlastimil Babka <vbabka@kernel.org>,\n\tlance.yang@linux.dev,\n\tlinux-kernel@vger.kernel.org,\n\tkernel-team@meta.com,\n\tmaddy@linux.ibm.com,\n\tmpe@ellerman.id.au,\n\tlinuxppc-dev@lists.ozlabs.org,\n\thca@linux.ibm.com,\n\tgor@linux.ibm.com,\n\tagordeev@linux.ibm.com,\n\tborntraeger@linux.ibm.com,\n\tsvens@linux.ibm.com,\n\tlinux-s390@vger.kernel.org,\n\tUsama Arif <usama.arif@linux.dev>", "Subject": "[v3 06/24] mm: thp: handle split failure in wp_huge_pmd()", "Date": "Thu, 26 Mar 2026 19:08:48 -0700", "Message-ID": "<20260327021403.214713-7-usama.arif@linux.dev>", "In-Reply-To": "<20260327021403.214713-1-usama.arif@linux.dev>", "References": "<20260327021403.214713-1-usama.arif@linux.dev>", "X-Mailing-List": "linuxppc-dev@lists.ozlabs.org", "List-Id": "<linuxppc-dev.lists.ozlabs.org>", "List-Help": "<mailto:linuxppc-dev+help@lists.ozlabs.org>", "List-Owner": "<mailto:linuxppc-dev+owner@lists.ozlabs.org>", "List-Post": "<mailto:linuxppc-dev@lists.ozlabs.org>", "List-Archive": "<https://lore.kernel.org/linuxppc-dev/>,\n <https://lists.ozlabs.org/pipermail/linuxppc-dev/>", "List-Subscribe": "<mailto:linuxppc-dev+subscribe@lists.ozlabs.org>,\n <mailto:linuxppc-dev+subscribe-digest@lists.ozlabs.org>,\n <mailto:linuxppc-dev+subscribe-nomail@lists.ozlabs.org>", "List-Unsubscribe": "<mailto:linuxppc-dev+unsubscribe@lists.ozlabs.org>", "Precedence": "list", "MIME-Version": "1.0", "Content-Transfer-Encoding": "8bit", "X-Migadu-Flow": "FLOW_OUT", "X-Spam-Status": "No, score=-0.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID,\n\tDKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_LOW,SPF_HELO_PASS,SPF_PASS\n\tautolearn=disabled version=4.0.1 OzLabs 8", "X-Spam-Checker-Version": "SpamAssassin 4.0.1 (2024-03-25) on lists.ozlabs.org" }, "content": "wp_huge_pmd() splits the PMD when COW or write-notify must be handled at\nPTE level (e.g., shared/file VMAs, userfaultfd). It then returns\nVM_FAULT_FALLBACK so the fault handler retries at PTE granularity.\nIf the split fails, the PMD is still huge. The PTE fault path cannot\nhandle a huge PMD entry.\nReturn VM_FAULT_OOM on split failure, which signals the fault handler to\ninvoke the OOM killer or return -ENOMEM to userspace. This is similar to\nwhat __handle_mm_fault would do if p4d_alloc or pud_alloc fails.\n\nSigned-off-by: Usama Arif <usama.arif@linux.dev>\n---\n mm/memory.c | 9 +++++++--\n 1 file changed, 7 insertions(+), 2 deletions(-)", "diff": "diff --git a/mm/memory.c b/mm/memory.c\nindex caf97c48cb166..b99ec3ffc18d1 100644\n--- a/mm/memory.c\n+++ b/mm/memory.c\n@@ -6328,8 +6328,13 @@ static inline vm_fault_t wp_huge_pmd(struct vm_fault *vmf)\n \t}\n \n split:\n-\t/* COW or write-notify handled on pte level: split pmd. */\n-\t__split_huge_pmd(vma, vmf->pmd, vmf->address, false);\n+\t/*\n+\t * COW or write-notify handled on pte level: split pmd.\n+\t * If split fails, the PMD is still huge so falling back\n+\t * to PTE handling would be incorrect.\n+\t */\n+\tif (__split_huge_pmd(vma, vmf->pmd, vmf->address, false))\n+\t\treturn VM_FAULT_OOM;\n \n \treturn VM_FAULT_FALLBACK;\n }\n", "prefixes": [ "v3", "06/24" ] }