hi Kirill,
As Mike reported it below, your 5-level paging related upstream commit 83e3c48729d9 and all its followup fixes:
83e3c48729d9: mm/sparsemem: Allocate mem_section at runtime for CONFIG_SPARSEMEM_EXTREME=y 629a359bdb0e: mm/sparsemem: Fix ARM64 boot crash when CONFIG_SPARSEMEM_EXTREME=y d09cfbbfa0f7: mm/sparse.c: wrong allocation for mem_section
... still breaks kexec - and that now regresses -stable as well.
Given that 5-level paging now syntactically depends on having this commit, if we fully revert this then we'll have to disable 5-level paging as well.
Thanks,
Ingo
* Mike Galbraith efault@gmx.de wrote:
On Fri, 2017-12-22 at 09:45 +0100, Greg Kroah-Hartman wrote:
4.14-stable review patch. If anyone has any objections, please let me know.
FYI, this broke kdump, or rather the makedumpfile part thereof. Forward looking wreckage is par for the kdump course, but...
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
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)