From 0a34891443e6c7936776e983bac92af07c13b183 Mon Sep 17 00:00:00 2001 From: Yasuaki Ishimatsu Date: Thu, 26 Jun 2014 10:42:18 +1000 Subject: [PATCH] x86,mem-hotplug: pass sync_global_pgds() a correct argument in remove_pagetable() When hot-adding memory after hot-removing memory, following call traces are shown: kernel BUG at arch/x86/mm/init_64.c:206! ... [] kernel_physical_mapping_init+0x1b2/0x1d2 [] init_memory_mapping+0x1d4/0x380 [] arch_add_memory+0x3d/0xd0 [] add_memory+0xb9/0x1b0 [] acpi_memory_device_add+0x1af/0x28e [] acpi_bus_device_attach+0x8c/0xf0 [] acpi_ns_walk_namespace+0xc8/0x17f [] ? acpi_bus_type_and_status+0xb7/0xb7 [] ? acpi_bus_type_and_status+0xb7/0xb7 [] acpi_walk_namespace+0x95/0xc5 [] acpi_bus_scan+0x9a/0xc2 [] acpi_scan_bus_device_check+0x8b/0x12e [] acpi_scan_device_check+0x13/0x15 [] acpi_os_execute_deferred+0x25/0x32 [] process_one_work+0x17b/0x460 [] worker_thread+0x11b/0x400 [] ? rescuer_thread+0x400/0x400 [] kthread+0xcf/0xe0 [] ? kthread_create_on_node+0x140/0x140 [] ret_from_fork+0x7c/0xb0 [] ? kthread_create_on_node+0x140/0x140 The patch-sets fix the issue. This patch (of 2): remove_pagetable() gets start argument and passes the argument to sync_global_pgds(). In this case, the argument must not be modified. If the argument is modified and passed to sync_global_pgds(), sync_global_pgds() does not correctly synchronize PGD to PGD entries of all processes MM since synchronized range of memory [start, end] is wrong. Unfortunately the start argument is modified in remove_pagetable(). So this patch fixes the issue. Signed-off-by: Yasuaki Ishimatsu Cc: Thomas Gleixner Cc: Ingo Molnar Cc: H. Peter Anvin Cc: Tang Chen Acked-by: Toshi Kani Cc: Gu Zheng Cc: Zhang Yanfei Signed-off-by: Andrew Morton --- arch/x86/mm/init_64.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index df1a9927ad29..a5b245d3f0cd 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -975,19 +975,20 @@ static void __meminit remove_pagetable(unsigned long start, unsigned long end, bool direct) { unsigned long next; + unsigned long addr; pgd_t *pgd; pud_t *pud; bool pgd_changed = false; - for (; start < end; start = next) { - next = pgd_addr_end(start, end); + for (addr = start; addr < end; addr = next) { + next = pgd_addr_end(addr, end); - pgd = pgd_offset_k(start); + pgd = pgd_offset_k(addr); if (!pgd_present(*pgd)) continue; pud = (pud_t *)pgd_page_vaddr(*pgd); - remove_pud_table(pud, start, next, direct); + remove_pud_table(pud, addr, next, direct); if (free_pud_table(pud, pgd)) pgd_changed = true; } -- 2.39.5