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[71.184.117.43]) by smtp.gmail.com with ESMTPSA id f8sm1123924qkf.96.2018.12.18.17.57.37 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 18 Dec 2018 17:57:38 -0800 (PST) From: Qian Cai To: akpm@linux-foundation.org Cc: mingo@kernel.org, mhocko@suse.com, hpa@zytor.com, mgorman@techsingularity.net, tglx@linutronix.de, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Qian Cai Subject: [PATCH] mm: skip checking poison pattern for page_to_nid() Date: Tue, 18 Dec 2018 20:57:32 -0500 Message-Id: <20181219015732.26179-1-cai@lca.pw> X-Mailer: git-send-email 2.17.2 (Apple Git-113) In-Reply-To: <1545172285.18411.26.camel@lca.pw> References: <1545172285.18411.26.camel@lca.pw> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Kernel panic with page_owner=on CONFIG_DEBUG_VM_PGFLAGS=y PAGE_OWNER=y NODE_NOT_IN_PAGE_FLAGS=n This is due to f165b378bbd (mm: uninitialized struct page poisoning sanity checking) shoots itself in the foot. [ 11.917212] page:ffffea0004200000 is uninitialized and poisoned [ 11.917220] raw: ffffffffffffffff ffffffffffffffff ffffffffffffffff ffffffffffffffff [ 11.921745] raw: ffffffffffffffff ffffffffffffffff ffffffffffffffff ffffffffffffffff [ 11.924523] page dumped because: VM_BUG_ON_PAGE(PagePoisoned(p)) [ 11.926498] page_owner info is not active (free page?) [ 12.329560] kernel BUG at include/linux/mm.h:990! [ 12.337632] RIP: 0010:init_page_owner+0x486/0x520 At first, start_kernel setup_arch pagetable_init paging_init sparse_init sparse_init_nid sparse_buffer_init memblock_virt_alloc_try_nid_raw It poisons all the allocated pages there. memset(ptr, PAGE_POISON_PATTERN, size) Later, page_ext_init invoke_init_callbacks init_section_page_ext init_page_owner init_early_allocated_pages init_zones_in_node init_pages_in_zone lookup_page_ext page_to_nid PF_POISONED_CHECK <--- panic here. This because all allocated pages are not initialized until later. init_pages_in_zone __set_page_owner_handle Fixes: f165b378bbd (mm: uninitialized struct page poisoning sanity checking) Signed-off-by: Qian Cai --- include/linux/mm.h | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 5411de93a363..f083f366ea90 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -985,9 +985,7 @@ extern int page_to_nid(const struct page *page); #else static inline int page_to_nid(const struct page *page) { - struct page *p = (struct page *)page; - - return (PF_POISONED_CHECK(p)->flags >> NODES_PGSHIFT) & NODES_MASK; + return (page->flags >> NODES_PGSHIFT) & NODES_MASK; } #endif -- 2.17.2 (Apple Git-113)