From mboxrd@z Thu Jan 1 00:00:00 1970 From: lauraa@codeaurora.org (Laura Abbott) Date: Thu, 22 Jan 2015 16:33:20 -0800 Subject: [PATCHv2] mm: Don't offset memmap for flatmem In-Reply-To: <20150122162021.aa861aeb53c22206a19ebbcb@linux-foundation.org> References: <1421804273-29947-1-git-send-email-lauraa@codeaurora.org> <1421888500-24364-1-git-send-email-lauraa@codeaurora.org> <20150122162021.aa861aeb53c22206a19ebbcb@linux-foundation.org> Message-ID: <54C196D0.6040900@codeaurora.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 1/22/2015 4:20 PM, Andrew Morton wrote: > On Wed, 21 Jan 2015 17:01:40 -0800 Laura Abbott wrote: > >> Srinivas Kandagatla reported bad page messages when trying to >> remove the bottom 2MB on an ARM based IFC6410 board >> >> BUG: Bad page state in process swapper pfn:fffa8 >> page:ef7fb500 count:0 mapcount:0 mapping: (null) index:0x0 >> flags: 0x96640253(locked|error|dirty|active|arch_1|reclaim|mlocked) >> page dumped because: PAGE_FLAGS_CHECK_AT_FREE flag(s) set >> bad because of flags: >> flags: 0x200041(locked|active|mlocked) >> Modules linked in: >> CPU: 0 PID: 0 Comm: swapper Not tainted 3.19.0-rc3-00007-g412f9ba-dirty #816 >> Hardware name: Qualcomm (Flattened Device Tree) >> [] (unwind_backtrace) from [] (show_stack+0x20/0x24) >> [] (show_stack) from [] (dump_stack+0x80/0x9c) >> [] (dump_stack) from [] (bad_page+0xc8/0x128) >> [] (bad_page) from [] (free_pages_prepare+0x168/0x1e0) >> [] (free_pages_prepare) from [] (free_hot_cold_page+0x3c/0x174) >> [] (free_hot_cold_page) from [] (__free_pages+0x54/0x58) >> [] (__free_pages) from [] (free_highmem_page+0x38/0x88) >> [] (free_highmem_page) from [] (mem_init+0x240/0x430) >> [] (mem_init) from [] (start_kernel+0x1e4/0x3c8) >> [] (start_kernel) from [<80208074>] (0x80208074) >> Disabling lock debugging due to kernel taint >> >> Removing the lower 2MB made the start of the lowmem zone to no longer >> be page block aligned. IFC6410 uses CONFIG_FLATMEM where >> alloc_node_mem_map allocates memory for the mem_map. alloc_node_mem_map >> will offset for unaligned nodes with the assumption the pfn/page >> translation functions will account for the offset. The functions for >> CONFIG_FLATMEM do not offset however, resulting in overrunning >> the memmap array. Just use the allocated memmap without any offset >> when running with CONFIG_FLATMEM to avoid the overrun. >> > > I don't think v2 addressed Vlastimil's review comment? > We're still adding the offset to node_mem_map and then subtracting it from just mem_map. Did I miss another comment somewhere? -- Qualcomm Innovation Center, Inc. Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project