* [PATCH 3/3] fork: allocate vmapped kernel stacks for cache when a cpu is up
@ 2017-02-03 15:33 Hoeun Ryu
0 siblings, 0 replies; only message in thread
From: Hoeun Ryu @ 2017-02-03 15:33 UTC (permalink / raw)
To: Andrew Morton, Michal Hocko, Ingo Molnar, Andy Lutomirski,
Kees Cook, Eric W. Biederman, Mateusz Guzik
Cc: linux-kernel, kernel-hardening, Hoeun Ryu
when a cpu is up, predefined number of stacks are allocated and cached
immediately.
Signed-off-by: Hoeun Ryu <hoeun.ryu@gmail.com>
---
kernel/fork.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/kernel/fork.c b/kernel/fork.c
index 50de6cf..ee4067d 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -194,6 +194,21 @@ static int alloc_vm_stack_cache(unsigned int cpu)
vm_stack_cache->cur = 0;
vm_stack_cache->nr = 0;
+ for (i = 0; i < NR_CACHED_STACKS; i++) {
+ void *stack = __vmalloc_node_range(THREAD_SIZE, THREAD_SIZE,
+ VMALLOC_START, VMALLOC_END,
+ THREADINFO_GFP | __GFP_HIGHMEM,
+ PAGE_KERNEL,
+ 0, cpu_to_node(cpu),
+ __builtin_return_address(0));
+ if (!stack)
+ return -ENOMEM;
+
+ vm_stacks[i] = find_vm_area(stack);
+ vm_stack_cache->cur++;
+ vm_stack_cache->nr++;
+ }
+
return 0;
}
--
2.7.4
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