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Thu, 6 Mar 2025 22:45:06 +0000 (UTC) Received: from fedora.redhat.com (unknown [10.22.88.191]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id E540B18001D3; Thu, 6 Mar 2025 22:45:04 +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 v3 2/3] mm: page_table_check: use new iteration API Date: Thu, 6 Mar 2025 17:44:51 -0500 Message-ID: In-Reply-To: References: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 X-Rspam-User: X-Rspamd-Queue-Id: 9034D40007 X-Rspamd-Server: rspam09 X-Stat-Signature: 3xre4y1onuiaoinj3trcj934u6876q6f X-HE-Tag: 1741301122-505153 X-HE-Meta: U2FsdGVkX1+a/Ps5vVemgjd5gWvyruJz8xpFVfj9uxLuZUYLFzj0UlX35zaID2imdwGs9RwCZb9tfvt/74BTtewEPGUdy/umNNUipGsNlrcAz5NDPjdCy9QDy0eIrOnXHG59s4wquDEWsTalObtZ4hPUbiMSqZpE06gGk6CQzHqRS1Ml7F9oXC0p4QyXZ1JnP6m0XOm1WNSTKbULGeBGIJbW0Ksp1Ld3TUZGUfoKEtiTOMQZ0GC1RLMv6Jim0VcXpWBo388+jO18rpomfNMBCVOKX4WMMR969Z958KlXuxEHsNl1+H4Qx2WkVd+pEJa32Wy8DibnRZz1la/BvK1KsG8W086J/6F5J7svkLflN08wMgK5iHttTUFINlkKH9CFOQevqOlu3j8elAoT/nTbIinDPZn5lTSsOM2c0aJ31WLZy69UBqDIQU3gqm9Zl20qa+XvRvUnxlVSjQUuNT6uO1U2qem22STzEWaeffqTuX8Ge6iblbF1pbhqbYRo5tIiIOJyMStlZo4t4EFsc6KFqoJFqLk5qxwYsLRyvVru2wkDyRMaPYLLoavUIgHn1NSXl/DtoTMk0Toa4Xc/pPP8XQGGWMfcTfBCVOlBLyYJvkKPvl8+5icziuM/QYML/19LbP4b5b4Kt4H5efO7UWtz88u8BV/0k25LHEA5KPXVpGBVEEHzJ2H7LKrBGMnPhWjhSs/QtpJ/l9Uax7JQevLaEnGmFkGw3zKMqay7dE9rIgGwyTTziRlfWchyLCp50hhLO/USixCxeiMrK5/2mZxNWX9hFjk63G9fn8G253ylWiQsZ1YyS7RiSacSj/YMvoo6KjLDykiUlFyPlS6G5xu1GNwmLKvI/dZc7dkztRZn4voNRP+BtwuUUTBiNZqY3yEM8shavU0d6D0ja7B/Rh0MQ6E2V1t6zI267lG1PksRyzg9oFjc0ODrrYHBdbP0kfOwlkTmG2/N/3urYlSuLNA 3gm+HP/x 8ekIMH8W6JZbicP0zcF8k53004p6XRevadqK+fXjS/ruwPu6ToKKRAvtwyw6AMmz3womzKj5EbIc3h5kgyfG8XDlRcLz5e+qT3LcYZsuTaMKnxLdkpeZSK37Kfdfb8n4kRDjfrSjVhE2wLzwdzPstZ4h3wC5F/vHvTVyCloYSQqbiqEqCBGp8to2qJU0klVnnVyuAdlj0jmac6+Ekp8+LGcEcxf0sBODfIAnSoP9hiZ7v4T4BbDiUJHz6fhhPOWfVfyV1Qvjq5ayNjym0lDLqpjiD5WSc4r5miJrGWq9Nfk/GlBfMOPmkNcX8kzpI/weVL5iZl/87G9xyFrRgcXTYFiVb/aYgKnDSzmOIJ0SkVhbWtLDIOpkV7KAiGEhjxoOD0nGwnQ2B2xP+psEofvrgykGBWw== 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") Acked-by: David Hildenbrand Signed-off-by: Luiz Capitulino --- 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..e11bebf23e36f 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(page, 1 << 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)