This is a note to let you know that I've just added the patch titled
xtensa: fix high memory/reserved memory collision
to the 4.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: xtensa-fix-high-memory-reserved-memory-collision.patch and it can be found in the queue-4.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From 6ac5a11dc674bc5016ea716e8082fff61f524dc1 Mon Sep 17 00:00:00 2001
From: Max Filippov jcmvbkbc@gmail.com Date: Tue, 13 Feb 2018 15:31:05 -0800 Subject: xtensa: fix high memory/reserved memory collision
From: Max Filippov jcmvbkbc@gmail.com
commit 6ac5a11dc674bc5016ea716e8082fff61f524dc1 upstream.
Xtensa memory initialization code frees high memory pages without checking whether they are in the reserved memory regions or not. That results in invalid value of totalram_pages and duplicate page usage by CMA and highmem. It produces a bunch of BUGs at startup looking like this:
BUG: Bad page state in process swapper pfn:70800 page:be60c000 count:0 mapcount:-127 mapping: (null) index:0x1 flags: 0x80000000() raw: 80000000 00000000 00000001 ffffff80 00000000 be60c014 be60c014 0000000a page dumped because: nonzero mapcount Modules linked in: CPU: 0 PID: 1 Comm: swapper Tainted: G B 4.16.0-rc1-00015-g7928b2cbe55b-dirty #23 Stack: bd839d33 00000000 00000018 ba97b64c a106578c bd839d70 be60c000 00000000 a1378054 bd86a000 00000003 ba97b64c a1066166 bd839da0 be60c000 ffe00000 a1066b58 bd839dc0 be504000 00000000 000002f4 bd838000 00000000 0000001e Call Trace: [<a1065734>] bad_page+0xac/0xd0 [<a106578c>] free_pages_check_bad+0x34/0x4c [<a1066166>] __free_pages_ok+0xae/0x14c [<a1066b58>] __free_pages+0x30/0x64 [<a1365de5>] init_cma_reserved_pageblock+0x35/0x44 [<a13682dc>] cma_init_reserved_areas+0xf4/0x148 [<a10034b8>] do_one_initcall+0x80/0xf8 [<a1361c16>] kernel_init_freeable+0xda/0x13c [<a125b59d>] kernel_init+0x9/0xd0 [<a1004304>] ret_from_kernel_thread+0xc/0x18
Only free high memory pages that are not reserved.
Cc: stable@vger.kernel.org Signed-off-by: Max Filippov jcmvbkbc@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/xtensa/mm/init.c | 70 +++++++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 63 insertions(+), 7 deletions(-)
--- a/arch/xtensa/mm/init.c +++ b/arch/xtensa/mm/init.c @@ -79,19 +79,75 @@ void __init zones_init(void) free_area_init_node(0, zones_size, ARCH_PFN_OFFSET, NULL); }
+#ifdef CONFIG_HIGHMEM +static void __init free_area_high(unsigned long pfn, unsigned long end) +{ + for (; pfn < end; pfn++) + free_highmem_page(pfn_to_page(pfn)); +} + +static void __init free_highpages(void) +{ + unsigned long max_low = max_low_pfn; + struct memblock_region *mem, *res; + + reset_all_zones_managed_pages(); + /* set highmem page free */ + for_each_memblock(memory, mem) { + unsigned long start = memblock_region_memory_base_pfn(mem); + unsigned long end = memblock_region_memory_end_pfn(mem); + + /* Ignore complete lowmem entries */ + if (end <= max_low) + continue; + + if (memblock_is_nomap(mem)) + continue; + + /* Truncate partial highmem entries */ + if (start < max_low) + start = max_low; + + /* Find and exclude any reserved regions */ + for_each_memblock(reserved, res) { + unsigned long res_start, res_end; + + res_start = memblock_region_reserved_base_pfn(res); + res_end = memblock_region_reserved_end_pfn(res); + + if (res_end < start) + continue; + if (res_start < start) + res_start = start; + if (res_start > end) + res_start = end; + if (res_end > end) + res_end = end; + if (res_start != start) + free_area_high(start, res_start); + start = res_end; + if (start == end) + break; + } + + /* And now free anything which remains */ + if (start < end) + free_area_high(start, end); + } +} +#else +static void __init free_highpages(void) +{ +} +#endif + /* * Initialize memory pages. */
void __init mem_init(void) { -#ifdef CONFIG_HIGHMEM - unsigned long tmp; - - reset_all_zones_managed_pages(); - for (tmp = max_low_pfn; tmp < max_pfn; tmp++) - free_highmem_page(pfn_to_page(tmp)); -#endif + free_highpages();
max_mapnr = max_pfn - ARCH_PFN_OFFSET; high_memory = (void *)__va(max_low_pfn << PAGE_SHIFT);
Patches currently in stable-queue which might be from jcmvbkbc@gmail.com are
queue-4.15/xtensa-fix-high-memory-reserved-memory-collision.patch