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mprotect: do not set page table writable for cow pages

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Change-Id: If8b0bb56e7dae59aa9dc3d745a4cc4e43bf4bf9a
This commit is contained in:
Dominique MARTINET
2018-05-25 03:10:10 +02:00
committed by Dominique Martinet
parent 130751ff66
commit 81699345cc
1 changed files with 14 additions and 0 deletions
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14
kernel/process.c
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@ -1438,6 +1438,20 @@ int change_prot_process_memory_range(struct process_vm *vm,
clrattr = oldattr & ~newattr;
setattr = newattr & ~oldattr;
/*
* If this is a file mapping don't set any new prot write.
* We need to keep the page table read-only to trigger a page
* fault for copy-on-write later on
*/
if (range->memobj && (range->flag & VR_PRIVATE)) {
setattr &= ~PTATTR_WRITABLE;
if (clrattr == setattr == 0) {
range->flag = newflag;
error = 0;
goto out;
}
}
ihk_mc_spinlock_lock_noirq(&vm->page_table_lock);
error = ihk_mc_pt_change_attr_range(vm->address_space->page_table,
(void *)range->start, (void *)range->end,