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percpu, sparc64: fix sparse possible cpu map handling 

percpu code has been assuming num_possible_cpus() == nr_cpu_ids which
is incorrect if cpu_possible_map contains holes.  This causes percpu
code to access beyond allocated memories and vmalloc areas.  On a
sparc64 machine with cpus 0 and 2 (u60), this triggers the following
warning or fails boot.

 WARNING: at /devel/tj/os/work/mm/vmalloc.c:106 vmap_page_range_noflush+0x1f0/0x240()
 Modules linked in:
 Call Trace:
  [00000000004b17d0] vmap_page_range_noflush+0x1f0/0x240
  [00000000004b1840] map_vm_area+0x20/0x60
  [00000000004b1950] __vmalloc_area_node+0xd0/0x160
  [0000000000593434] deflate_init+0x14/0xe0
  [0000000000583b94] __crypto_alloc_tfm+0xd4/0x1e0
  [00000000005844f0] crypto_alloc_base+0x50/0xa0
  [000000000058b898] alg_test_comp+0x18/0x80
  [000000000058dad4] alg_test+0x54/0x180
  [000000000058af00] cryptomgr_test+0x40/0x60
  [0000000000473098] kthread+0x58/0x80
  [000000000042b590] kernel_thread+0x30/0x60
  [0000000000472fd0] kthreadd+0xf0/0x160
 ---[ end trace 429b268a213317ba ]---

This patch fixes generic percpu functions and sparc64
setup_per_cpu_areas() so that they handle sparse cpu_possible_map
properly.

Please note that on x86, cpu_possible_map() doesn't contain holes and
thus num_possible_cpus() == nr_cpu_ids and this patch doesn't cause
any behavior difference.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: David S. Miller <davem@davemloft.net>
Cc: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Tejun Heo 2009-07-21 17:11:50 +09:00
parent d6647bdf98
commit 74d46d6b2d
3 changed files with 27 additions and 24 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
arch/sparc/kernel/smp_64.c
View File

@ -1499,7 +1499,7 @@ void __init setup_per_cpu_areas(void)
dyn_size = pcpur_size - static_size - PERCPU_MODULE_RESERVE;
ptrs_size = PFN_ALIGN(num_possible_cpus() * sizeof(pcpur_ptrs[0]));
ptrs_size = PFN_ALIGN(nr_cpu_ids * sizeof(pcpur_ptrs[0]));
pcpur_ptrs = alloc_bootmem(ptrs_size);
for_each_possible_cpu(cpu) {
@ -1514,7 +1514,7 @@ void __init setup_per_cpu_areas(void)
/* allocate address and map */
vm.flags = VM_ALLOC;
vm.size = num_possible_cpus() * PCPU_CHUNK_SIZE;
vm.size = nr_cpu_ids * PCPU_CHUNK_SIZE;
vm_area_register_early(&vm, PCPU_CHUNK_SIZE);
for_each_possible_cpu(cpu) {

14
arch/x86/kernel/setup_percpu.c
View File

@ -165,7 +165,7 @@ static ssize_t __init setup_pcpu_lpage(size_t static_size, bool chosen)
if (!chosen) {
size_t vm_size = VMALLOC_END - VMALLOC_START;
size_t tot_size = num_possible_cpus() * PMD_SIZE;
size_t tot_size = nr_cpu_ids * PMD_SIZE;
/* on non-NUMA, embedding is better */
if (!pcpu_need_numa())
@ -199,7 +199,7 @@ static ssize_t __init setup_pcpu_lpage(size_t static_size, bool chosen)
dyn_size = pcpul_size - static_size - PERCPU_FIRST_CHUNK_RESERVE;
/* allocate pointer array and alloc large pages */
map_size = PFN_ALIGN(num_possible_cpus() * sizeof(pcpul_map[0]));
map_size = PFN_ALIGN(nr_cpu_ids * sizeof(pcpul_map[0]));
pcpul_map = alloc_bootmem(map_size);
for_each_possible_cpu(cpu) {
@ -228,7 +228,7 @@ static ssize_t __init setup_pcpu_lpage(size_t static_size, bool chosen)
/* allocate address and map */
pcpul_vm.flags = VM_ALLOC;
pcpul_vm.size = num_possible_cpus() * PMD_SIZE;
pcpul_vm.size = nr_cpu_ids * PMD_SIZE;
vm_area_register_early(&pcpul_vm, PMD_SIZE);
for_each_possible_cpu(cpu) {
@ -250,8 +250,8 @@ static ssize_t __init setup_pcpu_lpage(size_t static_size, bool chosen)
PMD_SIZE, pcpul_vm.addr, NULL);
/* sort pcpul_map array for pcpu_lpage_remapped() */
for (i = 0; i < num_possible_cpus() - 1; i++)
for (j = i + 1; j < num_possible_cpus(); j++)
for (i = 0; i < nr_cpu_ids - 1; i++)
for (j = i + 1; j < nr_cpu_ids; j++)
if (pcpul_map[i].ptr > pcpul_map[j].ptr) {
struct pcpul_ent tmp = pcpul_map[i];
pcpul_map[i] = pcpul_map[j];
@ -288,7 +288,7 @@ void *pcpu_lpage_remapped(void *kaddr)
{
void *pmd_addr = (void *)((unsigned long)kaddr & PMD_MASK);
unsigned long offset = (unsigned long)kaddr & ~PMD_MASK;
int left = 0, right = num_possible_cpus() - 1;
int left = 0, right = nr_cpu_ids - 1;
int pos;
/* pcpul in use at all? */
@ -377,7 +377,7 @@ static ssize_t __init setup_pcpu_4k(size_t static_size)
pcpu4k_nr_static_pages = PFN_UP(static_size);
/* unaligned allocations can't be freed, round up to page size */
pages_size = PFN_ALIGN(pcpu4k_nr_static_pages * num_possible_cpus()
pages_size = PFN_ALIGN(pcpu4k_nr_static_pages * nr_cpu_ids
* sizeof(pcpu4k_pages[0]));
pcpu4k_pages = alloc_bootmem(pages_size);

33
mm/percpu.c
View File

@ -8,12 +8,12 @@
*
* This is percpu allocator which can handle both static and dynamic
* areas. Percpu areas are allocated in chunks in vmalloc area. Each
* chunk is consisted of num_possible_cpus() units and the first chunk
* is used for static percpu variables in the kernel image (special
* boot time alloc/init handling necessary as these areas need to be
* brought up before allocation services are running). Unit grows as
* necessary and all units grow or shrink in unison. When a chunk is
* filled up, another chunk is allocated. ie. in vmalloc area
* chunk is consisted of nr_cpu_ids units and the first chunk is used
* for static percpu variables in the kernel image (special boot time
* alloc/init handling necessary as these areas need to be brought up
* before allocation services are running). Unit grows as necessary
* and all units grow or shrink in unison. When a chunk is filled up,
* another chunk is allocated. ie. in vmalloc area
*
* c0 c1 c2
* ------------------- ------------------- ------------
@ -558,7 +558,7 @@ static void pcpu_free_area(struct pcpu_chunk *chunk, int freeme)
static void pcpu_unmap(struct pcpu_chunk *chunk, int page_start, int page_end,
bool flush_tlb)
{
unsigned int last = num_possible_cpus() - 1;
unsigned int last = nr_cpu_ids - 1;
unsigned int cpu;
/* unmap must not be done on immutable chunk */
@ -643,7 +643,7 @@ static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk, int off, int size,
*/
static int pcpu_map(struct pcpu_chunk *chunk, int page_start, int page_end)
{
unsigned int last = num_possible_cpus() - 1;
unsigned int last = nr_cpu_ids - 1;
unsigned int cpu;
int err;
@ -1067,9 +1067,9 @@ size_t __init pcpu_setup_first_chunk(pcpu_get_page_fn_t get_page_fn,
PFN_UP(size_sum));
pcpu_unit_size = pcpu_unit_pages << PAGE_SHIFT;
pcpu_chunk_size = num_possible_cpus() * pcpu_unit_size;
pcpu_chunk_size = nr_cpu_ids * pcpu_unit_size;
pcpu_chunk_struct_size = sizeof(struct pcpu_chunk)
+ num_possible_cpus() * pcpu_unit_pages * sizeof(struct page *);
+ nr_cpu_ids * pcpu_unit_pages * sizeof(struct page *);
if (dyn_size < 0)
dyn_size = pcpu_unit_size - static_size - reserved_size;
@ -1248,7 +1248,7 @@ ssize_t __init pcpu_embed_first_chunk(size_t static_size, size_t reserved_size,
} else
pcpue_unit_size = max_t(size_t, pcpue_size, PCPU_MIN_UNIT_SIZE);
chunk_size = pcpue_unit_size * num_possible_cpus();
chunk_size = pcpue_unit_size * nr_cpu_ids;
pcpue_ptr = __alloc_bootmem_nopanic(chunk_size, PAGE_SIZE,
__pa(MAX_DMA_ADDRESS));
@ -1259,12 +1259,15 @@ ssize_t __init pcpu_embed_first_chunk(size_t static_size, size_t reserved_size,
}
/* return the leftover and copy */
for_each_possible_cpu(cpu) {
for (cpu = 0; cpu < nr_cpu_ids; cpu++) {
void *ptr = pcpue_ptr + cpu * pcpue_unit_size;
free_bootmem(__pa(ptr + pcpue_size),
pcpue_unit_size - pcpue_size);
memcpy(ptr, __per_cpu_load, static_size);
if (cpu_possible(cpu)) {
free_bootmem(__pa(ptr + pcpue_size),
pcpue_unit_size - pcpue_size);
memcpy(ptr, __per_cpu_load, static_size);
} else
free_bootmem(__pa(ptr), pcpue_unit_size);
}
/* we're ready, commit */