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Wed, 19 Feb 2025 02:18:17 +0000 (UTC) Received: from fedora.redhat.com (unknown [10.22.65.50]) by mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 59B1D19560B9; Wed, 19 Feb 2025 02:18:15 +0000 (UTC) From: Luiz Capitulino To: linux-kernel@vger.kernel.org, linux-mm@kvack.org, david@redhat.com, yuzhao@google.com, pasha.tatashin@soleen.com Cc: akpm@linux-foundation.org, hannes@cmpxchg.org, muchun.song@linux.dev, luizcap@redhat.com Subject: [PATCH 2/4] mm: page_table_check: use new iteration API Date: Tue, 18 Feb 2025 21:17:48 -0500 Message-ID: <85f11743d259d5e4a1f47456fbcda82ff6db9ab3.1739931468.git.luizcap@redhat.com> In-Reply-To: References: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.0 on 10.30.177.15 X-Stat-Signature: jrcy9dbicw76915okcbrowuqh1kb3y9a X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 64E1440002 X-Rspam-User: X-HE-Tag: 1739931504-51527 X-HE-Meta: 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 vBE+hSYm mO5JnWx0UaTEdChav1+7V7OJ0Zsa+MhjzkXLYmjM1Y0l+XX7OZY8DfFiNwvPxB0i8AaN5x8MA2IwsOM8vwXhLWePMg7inhFLEPi5N4sIIJkGuJ/8Z230g35C77PhlxUm0pCE9JFPTuqP8iyEoUweNhMBrn2gJDEnGIMevSmOm9r/gEBAU78ApVKHKKdop8p0i7fI8e3UWTsTP4FNOqw5Ik/GeEjiQW+3Gq2Kn4t4XaSsHSscV0dAK4TXAo9wSu4fEN2hN+dFS+X2CcnZg1QOSIdpT73Zz1wUbgf0bSDYdVfg8S9vDlK2HnCL3zEDr8nue6bI1gg7zoUrxC+jTprSZvXY/Y9b57FNwGwy0+zNPIK82B1PAj9UBkxh9qQ== 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: The page_ext_next() function assumes that page extension objects for a page order allocation always reside in the same memory section, which may not be true and could lead to crashes. Use the new page_ext iteration API instead. Fixes: cf54f310d0d3 ("mm/hugetlb: use __GFP_COMP for gigantic folios") Signed-off-by: Luiz Capitulino Acked-by: David Hildenbrand --- mm/page_table_check.c | 39 ++++++++++++--------------------------- 1 file changed, 12 insertions(+), 27 deletions(-) diff --git a/mm/page_table_check.c b/mm/page_table_check.c index 509c6ef8de400..b52e04d31c809 100644 --- a/mm/page_table_check.c +++ b/mm/page_table_check.c @@ -62,24 +62,20 @@ static struct page_table_check *get_page_table_check(struct page_ext *page_ext) */ static void page_table_check_clear(unsigned long pfn, unsigned long pgcnt) { + struct page_ext_iter iter; struct page_ext *page_ext; struct page *page; - unsigned long i; bool anon; if (!pfn_valid(pfn)) return; page = pfn_to_page(pfn); - page_ext = page_ext_get(page); - - if (!page_ext) - return; - BUG_ON(PageSlab(page)); anon = PageAnon(page); - for (i = 0; i < pgcnt; i++) { + rcu_read_lock(); + for_each_page_ext(page, pgcnt, page_ext, iter) { struct page_table_check *ptc = get_page_table_check(page_ext); if (anon) { @@ -89,9 +85,8 @@ static void page_table_check_clear(unsigned long pfn, unsigned long pgcnt) BUG_ON(atomic_read(&ptc->anon_map_count)); BUG_ON(atomic_dec_return(&ptc->file_map_count) < 0); } - page_ext = page_ext_next(page_ext); } - page_ext_put(page_ext); + rcu_read_unlock(); } /* @@ -102,24 +97,20 @@ static void page_table_check_clear(unsigned long pfn, unsigned long pgcnt) static void page_table_check_set(unsigned long pfn, unsigned long pgcnt, bool rw) { + struct page_ext_iter iter; struct page_ext *page_ext; struct page *page; - unsigned long i; bool anon; if (!pfn_valid(pfn)) return; page = pfn_to_page(pfn); - page_ext = page_ext_get(page); - - if (!page_ext) - return; - BUG_ON(PageSlab(page)); anon = PageAnon(page); - for (i = 0; i < pgcnt; i++) { + rcu_read_lock(); + for_each_page_ext(page, pgcnt, page_ext, iter) { struct page_table_check *ptc = get_page_table_check(page_ext); if (anon) { @@ -129,9 +120,8 @@ static void page_table_check_set(unsigned long pfn, unsigned long pgcnt, BUG_ON(atomic_read(&ptc->anon_map_count)); BUG_ON(atomic_inc_return(&ptc->file_map_count) < 0); } - page_ext = page_ext_next(page_ext); } - page_ext_put(page_ext); + rcu_read_unlock(); } /* @@ -140,24 +130,19 @@ static void page_table_check_set(unsigned long pfn, unsigned long pgcnt, */ void __page_table_check_zero(struct page *page, unsigned int order) { + struct page_ext_iter iter; struct page_ext *page_ext; - unsigned long i; BUG_ON(PageSlab(page)); - page_ext = page_ext_get(page); - - if (!page_ext) - return; - - for (i = 0; i < (1ul << order); i++) { + rcu_read_lock(); + for_each_page_ext_order(page, order, page_ext, iter) { struct page_table_check *ptc = get_page_table_check(page_ext); BUG_ON(atomic_read(&ptc->anon_map_count)); BUG_ON(atomic_read(&ptc->file_map_count)); - page_ext = page_ext_next(page_ext); } - page_ext_put(page_ext); + rcu_read_unlock(); } void __page_table_check_pte_clear(struct mm_struct *mm, pte_t pte)