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Fri, 11 Jul 2025 09:25:48 -0700 (PDT) Received: from [192.168.86.142] ([90.253.47.31]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-3b5e8e26c8bsm4822114f8f.88.2025.07.11.09.25.47 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 11 Jul 2025 09:25:48 -0700 (PDT) Message-ID: <136b4999-1c05-4d30-9521-d621196e6ba7@neon.tech> Date: Fri, 11 Jul 2025 17:25:47 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: [PATCH v5 3/4] x86/mm: Handle alloc failure in phys_*_init() From: Em Sharnoff To: linux-kernel@vger.kernel.org, x86@kernel.org, linux-mm@kvack.org Cc: Dave Hansen , Andy Lutomirski , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , "Edgecombe, Rick P" , Oleg Vasilev , Arthur Petukhovsky , Stefan Radig , Misha Sakhnov References: <4fe0984f-74dc-45fe-b2b6-bdd81ec15bac@neon.tech> Content-Language: en-US In-Reply-To: <4fe0984f-74dc-45fe-b2b6-bdd81ec15bac@neon.tech> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 220CEA0013 X-Stat-Signature: egxgckt6f4tc5jmtzun9mk74uetzr8zf X-Rspam-User: X-HE-Tag: 1752251149-127964 X-HE-Meta: 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 4xvCGjm1 gm4XZy7rw8Cv1mZ5QK5bxBE+lPU7DYZnjal/kwsEcSSWNvh63xUuWFZlYRzDT2kbum20rfdhmfw4qKfrsEKSm1+X40/jEqg/2eDBnDkVKO3TTjHC/n2Dtbtkdm2IvB1wDJy/i9P5gadIvxDVDBBDfO+BUh9OBaIAmMQ0eDkaXw30UxxqGAiSCin6ePGMIAAtnSgRvu/xxCrQMss+CLxvkbFJDe7FXnKxHg4jLndlsWj8VD7wXKuqp4YF0C72SlTOnL0Rn7FAVSiKV11pgkOoj0qwsvjyyvO4CzhZwjxL2EEc7fiKUCxSeKkrEu14ypjgZP55alayTepYFoSH8L3HjT8LXjenu33pciW1Ygm0Tz8CXRcKH7JhNK3wEP7KB0oQnP0bkwNErGKFtuX4kjjOZ6wYcHr5187xM8Yp4OHujkPqL2lC5Pbx7dtZbswLBM6vcH019 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: List-Subscribe: List-Unsubscribe: During memory hotplug, allocation failures in phys_*_init() aren't handled, which results in a null pointer dereference if they occur. This patch depends on the previous patch ("x86/mm: Allow error returns from phys_*_init()"). Signed-off-by: Em Sharnoff --- Changelog: - v4: Split this patch out from the error handling changes --- arch/x86/mm/init_64.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index ca71eaec1db5..eced309a4015 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -573,6 +573,8 @@ phys_pmd_init(pmd_t *pmd_page, unsigned long paddr, unsigned long paddr_end, } pte = alloc_low_page(); + if (!pte) + return -ENOMEM; paddr_last = phys_pte_init(pte, paddr, paddr_end, new_prot, init); spin_lock(&init_mm.page_table_lock); @@ -665,6 +667,8 @@ phys_pud_init(pud_t *pud_page, unsigned long paddr, unsigned long paddr_end, } pmd = alloc_low_page(); + if (!pmd) + return -ENOMEM; ret = phys_pmd_init(pmd, paddr, paddr_end, page_size_mask, prot, init); @@ -727,6 +731,8 @@ phys_p4d_init(p4d_t *p4d_page, unsigned long paddr, unsigned long paddr_end, } pud = alloc_low_page(); + if (!pud) + return -ENOMEM; ret = phys_pud_init(pud, paddr, __pa(vaddr_end), page_size_mask, prot, init); @@ -775,6 +781,8 @@ __kernel_physical_mapping_init(unsigned long paddr_start, } p4d = alloc_low_page(); + if (!p4d) + return -ENOMEM; ret = phys_p4d_init(p4d, __pa(vaddr), __pa(vaddr_end), page_size_mask, prot, init); -- 2.39.5