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bh=9JD/rGnP4z6sxKxaETbXjsBJM6V+qvu6dbKpCu5ZUWA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tVEge0BjP5FjjmbkU4psRvLiJd6bT9jhj1hm1Pa4vOf3rdbXx6C7YaGHpoigAPzqO vKdTkxgcIiMBdS93gKBCSr4GR2SegSbmQlxjG4YynzgaC0GjPSQiSEhJAQWBhw6M0z NnXaV/42Hn1Ubhy+dmLVElzAxQsZflcB0qbag9k0= 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, apopple@nvidia.com, rcampbell@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, ak@linux.intel.com, nao.horiguchi@gmail.com, mel@csn.ul.ie, j-nomura@ce.jp.nec.com, pfalcato@suse.de, tglx@kernel.org, dave.hansen@intel.com, jpoimboe@kernel.org, catalin.marinas@arm.com, will@kernel.org, linux-arm-kernel@lists.infradead.org, ryan.roberts@arm.com, anshuman.khandual@arm.com Subject: [PATCH v3 6/6] mm/mprotect: use huge_ptep_get() for hugetlb Date: Fri, 3 Jul 2026 11:41:59 +0000 Message-ID: <20260703114202.365553-7-dev.jain@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260703114202.365553-1-dev.jain@arm.com> References: <20260703114202.365553-1-dev.jain@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: C6A82C0011 X-Stat-Signature: kjuxdj4k34et3ztiizkzmde3ina9fsg8 X-HE-Tag: 1783079004-477458 X-HE-Meta: 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 y3+DXWgP 7ge/w6Nx3sX+PfndhkFoDNhb9bJ4cgCiaOcTsd4MDPwbNz8icsKSDXQNhqppTNpmUz9Jg+LhfuinvSPXlIvptFM322OhU7OHKAydAm3HU6tkJI5xEv5tC8xZlU52gtsVA8IcilfgFWFdPbl3/sGuL+8TZcZuwWyTVhXbp52bDQZL/cRNSrNxt/cb0qBoy/zUk/ky7EenSc+SWfJxytczcmVqordiqtwe8S1ct9mfbSJFyYeN6tr0ibvExWv0Lb4GTEquk+HCguAgZvhcidlKJ7DfCkkEmYb6z+Rq9WxaJncCkBsbSu1i8u4Ft55Fkb6ZZjPLeUFPTUSCtXOHROmRMlZ4TtzXX47tl8l1oH8RBSylRvpx1Mz4Kmw2Lzg== 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. So no need to backport - use the correct helper anyways. Fixes: 42e4089c7890 ("x86/speculation/l1tf: Disallow non privileged high MMIO PROT_NONE mappings") Reviewed-by: Muchun Song Signed-off-by: Dev Jain --- mm/mprotect.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/mm/mprotect.c b/mm/mprotect.c index 9cbf932b028cf..6360d8a378023 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)), - *(pgprot_t *)(walk->private)) ? - 0 : -EACCES; + const pte_t entry = huge_ptep_get(walk->mm, addr, pte); + + if (pfn_modify_allowed(pte_pfn(entry), *(pgprot_t *)(walk->private))) + return 0; + return -EACCESS; } +#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