On 22 December 2017 at 19:48, Dan Rue dan.rue@linaro.org wrote:
On Fri, Dec 22, 2017 at 09:45:08AM +0100, Greg Kroah-Hartman wrote:
4.14-stable review patch. If anyone has any objections, please let me know.
From: Kirill A. Shutemov kirill.shutemov@linux.intel.com
commit 83e3c48729d9ebb7af5a31a504f3fd6aff0348c4 upstream.
Size of the mem_section[] array depends on the size of the physical address space.
In preparation for boot-time switching between paging modes on x86-64 we need to make the allocation of mem_section[] dynamic, because otherwise we waste a lot of RAM: with CONFIG_NODE_SHIFT=10, mem_section[] size is 32kB for 4-level paging and 2MB for 5-level paging mode.
The patch allocates the array on the first call to sparse_memory_present_with_active_regions().
Signed-off-by: Kirill A. Shutemov kirill.shutemov@linux.intel.com Cc: Andrew Morton akpm@linux-foundation.org Cc: Andy Lutomirski luto@amacapital.net Cc: Borislav Petkov bp@suse.de Cc: Cyrill Gorcunov gorcunov@openvz.org Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Peter Zijlstra peterz@infradead.org Cc: Thomas Gleixner tglx@linutronix.de Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/20170929140821.37654-2-kirill.shutemov@linux.intel.... Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
This patch causes a boot failure on arm64.
Please drop this patch, or pick up the fix in:
commit 629a359bdb0e0652a8227b4ff3125431995fec6e Author: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Date: Tue Nov 7 11:33:37 2017 +0300 mm/sparsemem: Fix ARM64 boot crash when CONFIG_SPARSEMEM_EXTREME=ySee https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1527427.html
+1. Boot failed on arm64 without 629a359b mm/sparsemem: Fix ARM64 boot crash when CONFIG_SPARSEMEM_EXTREME=y
Boot Error log: -------------------- [ 0.000000] Unable to handle kernel NULL pointer dereference at virtual address 00000000 [ 0.000000] Mem abort info: [ 0.000000] Exception class = DABT (current EL), IL = 32 bits [ 0.000000] SET = 0, FnV = 0 [ 0.000000] EA = 0, S1PTW = 0 [ 0.000000] Data abort info: [ 0.000000] ISV = 0, ISS = 0x00000004 [ 0.000000] CM = 0, WnR = 0 [ 0.000000] [0000000000000000] user address but active_mm is swapper [ 0.000000] Internal error: Oops: 96000004 [#1] PREEMPT SMP [ 0.000000] Modules linked in: [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 4.14.9-rc1 #1 [ 0.000000] Hardware name: ARM Juno development board (r2) (DT) [ 0.000000] task: ffff0000091d9380 task.stack: ffff0000091c0000 [ 0.000000] PC is at memory_present+0x64/0xf4 [ 0.000000] LR is at memory_present+0x38/0xf4 [ 0.000000] pc : [<ffff0000090a1f54>] lr : [<ffff0000090a1f28>] pstate: 800000c5 [ 0.000000] sp : ffff0000091c3e80
More information, https://pastebin.com/KambxUwb
- Naresh
include/linux/mmzone.h | 6 +++++- mm/page_alloc.c | 10 ++++++++++ mm/sparse.c | 17 +++++++++++------ 3 files changed, 26 insertions(+), 7 deletions(-)
--- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -1152,13 +1152,17 @@ struct mem_section { #define SECTION_ROOT_MASK (SECTIONS_PER_ROOT - 1)
#ifdef CONFIG_SPARSEMEM_EXTREME -extern struct mem_section *mem_section[NR_SECTION_ROOTS]; +extern struct mem_section **mem_section; #else extern struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT]; #endif
static inline struct mem_section *__nr_to_section(unsigned long nr) { +#ifdef CONFIG_SPARSEMEM_EXTREME
if (!mem_section)return NULL;+#endif if (!mem_section[SECTION_NR_TO_ROOT(nr)]) return NULL; return &mem_section[SECTION_NR_TO_ROOT(nr)][nr & SECTION_ROOT_MASK]; --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -5651,6 +5651,16 @@ void __init sparse_memory_present_with_a unsigned long start_pfn, end_pfn; int i, this_nid;
+#ifdef CONFIG_SPARSEMEM_EXTREME
if (!mem_section) {unsigned long size, align;size = sizeof(struct mem_section) * NR_SECTION_ROOTS;align = 1 << (INTERNODE_CACHE_SHIFT);mem_section = memblock_virt_alloc(size, align);}+#endif
for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, &this_nid) memory_present(this_nid, start_pfn, end_pfn);} --- a/mm/sparse.c +++ b/mm/sparse.c @@ -23,8 +23,7 @@
- mem_section - memory sections, mem_map's for valid memory
*/ #ifdef CONFIG_SPARSEMEM_EXTREME -struct mem_section *mem_section[NR_SECTION_ROOTS]
____cacheline_internodealigned_in_smp;+struct mem_section **mem_section; #else struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT] ____cacheline_internodealigned_in_smp; @@ -101,7 +100,7 @@ static inline int sparse_index_init(unsi int __section_nr(struct mem_section* ms) { unsigned long root_nr;
struct mem_section* root;
struct mem_section *root = NULL; for (root_nr = 0; root_nr < NR_SECTION_ROOTS; root_nr++) { root = __nr_to_section(root_nr * SECTIONS_PER_ROOT);@@ -112,7 +111,7 @@ int __section_nr(struct mem_section* ms) break; }
VM_BUG_ON(root_nr == NR_SECTION_ROOTS);
VM_BUG_ON(!root); return (root_nr * SECTIONS_PER_ROOT) + (ms - root);} @@ -330,11 +329,17 @@ again: static void __init check_usemap_section_nr(int nid, unsigned long *usemap) { unsigned long usemap_snr, pgdat_snr;
static unsigned long old_usemap_snr = NR_MEM_SECTIONS;static unsigned long old_pgdat_snr = NR_MEM_SECTIONS;
static unsigned long old_usemap_snr;static unsigned long old_pgdat_snr; struct pglist_data *pgdat = NODE_DATA(nid); int usemap_nid;/* First call */if (!old_usemap_snr) {old_usemap_snr = NR_MEM_SECTIONS;old_pgdat_snr = NR_MEM_SECTIONS;}usemap_snr = pfn_to_section_nr(__pa(usemap) >> PAGE_SHIFT); pgdat_snr = pfn_to_section_nr(__pa(pgdat) >> PAGE_SHIFT); if (usemap_snr == pgdat_snr)