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authorHuacai Chen <chenhc@lemote.com>2013-03-17 15:50:14 +0400
committerRalf Baechle <ralf@linux-mips.org>2013-05-08 03:19:06 +0400
commit224786779d04bbcd5f61eaafc86bf8fee350388a (patch)
tree3db7c2ce9fdda70337de38ab344177b199153efb /arch/mips/include/asm/mmu_context.h
parent8759934e2b6bdb3a08a81fc14a6588f3321719b1 (diff)
downloadlinux-224786779d04bbcd5f61eaafc86bf8fee350388a.tar.xz
MIPS: Init new mmu_context for each possible CPU to avoid memory corruption
Currently, init_new_context() only for each online CPU, this may cause memory corruption when CPU hotplug and fork() happens at the same time. To avoid this, we make init_new_context() cover each possible CPU. Scenario: 1, CPU#1 is being offline; 2, On CPU#0, do_fork() call dup_mm() and copy a mm_struct to the child; 3, On CPU#0, dup_mm() call init_new_context(), since CPU#1 is offline and init_new_context() only covers the online CPUs, child has the same asid as its parent on CPU#1 (however, child's asid should be 0); 4, CPU#1 is being online; 5, Now, if both parent and child run on CPU#1, memory corruption (e.g. segfault, bus error, etc.) will occur. Signed-off-by: Huacai Chen <chenhc@lemote.com> Acked-by: David Daney <david.daney@cavium.com> Patchwork: http://patchwork.linux-mips.org/patch/4995/ Acked-by: John Crispin <blogic@openwrt.org>
Diffstat (limited to 'arch/mips/include/asm/mmu_context.h')
-rw-r--r--arch/mips/include/asm/mmu_context.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/mips/include/asm/mmu_context.h b/arch/mips/include/asm/mmu_context.h
index e81d719efcd1..49d220ccc145 100644
--- a/arch/mips/include/asm/mmu_context.h
+++ b/arch/mips/include/asm/mmu_context.h
@@ -133,7 +133,7 @@ init_new_context(struct task_struct *tsk, struct mm_struct *mm)
{
int i;
- for_each_online_cpu(i)
+ for_each_possible_cpu(i)
cpu_context(i, mm) = 0;
return 0;