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bh=qIVB6gHmZfbfjR8XMIsltlHaNah8ksCbKAdOfhqwEPs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fGeVw/tcCrootoIsfVQzEyvJihR1IT/gQKpPyfG2UPZ+f0p9YMIzfqbw+2XT0/O5R Tt48hVLDtCPKYUVM/fRRxpw6BRd4F3rXcYBux3do3SWHc4YwixZR6yH7j3YvnU9M35 bFbNTR4pdD5V3Wp8+6DBI1DZiSbicU9RrdLW0E3Q= From: Dev Jain To: muchun.song@linux.dev, osalvador@suse.de, akpm@linux-foundation.org, ljs@kernel.org, david@kernel.org, liam@infradead.org Cc: Dev Jain , riel@surriel.com, vbabka@kernel.org, harry@kernel.org, jannh@google.com, lance.yang@linux.dev, kas@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, rcampbell@nvidia.com, apopple@nvidia.com, ziy@nvidia.com, matthew.brost@intel.com, joshua.hahnjy@gmail.com, rakie.kim@sk.com, byungchul@sk.com, gourry@gourry.net, ying.huang@linux.alibaba.com, mel@csn.ul.ie, nao.horiguchi@gmail.com, ak@linux.intel.com, j-nomura@ce.jp.nec.com, pfalcato@suse.de, dave.hansen@intel.com, tglx@kernel.org, jpoimboe@kernel.org, ryan.roberts@arm.com, anshuman.khandual@arm.com Subject: [PATCH 5/5] mm/mprotect: use huge_ptep_get() for hugetlb Date: Thu, 25 Jun 2026 11:29:54 +0000 Message-ID: <20260625112955.3254283-6-dev.jain@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260625112955.3254283-1-dev.jain@arm.com> References: <20260625112955.3254283-1-dev.jain@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Stat-Signature: qb9gh7qqpbbr591bm57w69whkm1haxfa X-Rspam-User: X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 7FAA4C000C X-HE-Tag: 1782387058-588497 X-HE-Meta: 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 fhVU6yIZ ++eBOJsGBNJmI1BowfLGS8GRA53EBLQKIyVhNrI8mYE+Om8QL/xuEmV0DFTj0oGthKjYGth3p7f/NtJ59+amo59XVMjyknfMPGqhpVbPQKr90OnG7m7A93NFJMNo0Y9K4pbwQSsk+dLM82m8qmyv54wVf9dWXHs9NtAJvRvF2O/mgPJGdXYQvU1pwk/wfFjXzi86k5JLpyppvbdaJLFadjG6kPPHRBsI0nEDKsJ/o+1qtIWKW+EE3aONtWX8r0cQZAs3NOVycTor6tRGRUVNjkB1YZyaD43ZL/MLEt6kQyjIFA3OuAQ0eAKL69uk18NbCBkHRcU/qWKEdS32zAqyRyEZNOZyNXtBgMWae0uw6CVs2dIEqpuhkAmYF7g== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: prot_none_hugetlb_entry() is the hugetlb callback for the early mprotect(PROT_NONE) PFN permission walk on x86. The callback passes the decoded PFN to pfn_modify_allowed(). For a hugetlb callback, the pte pointer refers to a hugetlb entry. On architectures where hugetlb entries need huge_ptep_get(), reading that entry with ptep_get() can make the permission check use the wrong PFN. Use huge_ptep_get() before decoding the hugetlb PFN. Currently there is no path which can trigger a bug: huge_ptep_get() is a simple ptep_get() for x86, and the prot_none walk occurs only for x86. But use the correct helper anyways. Fixes: 42e4089c7890 ("x86/speculation/l1tf: Disallow non privileged high MMIO PROT_NONE mappings") Signed-off-by: Dev Jain --- mm/mprotect.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/mm/mprotect.c b/mm/mprotect.c index 9cbf932b028cf..23779632d18bf 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -699,14 +699,20 @@ static int prot_none_pte_entry(pte_t *pte, unsigned long addr, 0 : -EACCES; } +#ifdef CONFIG_HUGETLB_PAGE static int prot_none_hugetlb_entry(pte_t *pte, unsigned long hmask, unsigned long addr, unsigned long next, struct mm_walk *walk) { - return pfn_modify_allowed(pte_pfn(ptep_get(pte)), + pte_t entry = huge_ptep_get(walk->mm, addr, pte); + + return pfn_modify_allowed(pte_pfn(entry), *(pgprot_t *)(walk->private)) ? 0 : -EACCES; } +#else +#define prot_none_hugetlb_entry NULL +#endif static int prot_none_test(unsigned long addr, unsigned long next, struct mm_walk *walk) -- 2.43.0