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>
diff --git a/arch/x86/kernel/setup_percpu.c b/arch/x86/kernel/setup_percpu.c
index 29a3eef..07d8191 100644
--- a/arch/x86/kernel/setup_percpu.c
+++ b/arch/x86/kernel/setup_percpu.c
@@ -165,7 +165,7 @@
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 @@
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 @@
/* 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 @@
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 *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 @@
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);