On 22 December 2017 at 19:48, Dan Rue <dan.rue@xxxxxxxxxx> 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@xxxxxxxxxxxxxxx> >> >> 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@xxxxxxxxxxxxxxx> >> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> >> Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx> >> Cc: Borislav Petkov <bp@xxxxxxx> >> Cc: Cyrill Gorcunov <gorcunov@xxxxxxxxxx> >> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> >> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> >> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> >> Cc: linux-mm@xxxxxxxxx >> Link: http://lkml.kernel.org/r/20170929140821.37654-2-kirill.shutemov@xxxxxxxxxxxxxxx >> Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> >> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> > > 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@xxxxxxxxxxxxxxx> > Date: Tue Nov 7 11:33:37 2017 +0300 > > mm/sparsemem: Fix ARM64 boot crash when CONFIG_SPARSEMEM_EXTREME=y > > See https://www.mail-archive.com/linux-kernel@xxxxxxxxxxxxxxx/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 @@ >> * 1) 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) >> >> -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. 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