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Kernel: Don't CoW non-writable pages

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A page fault in a page marked for CoW should not trigger a CoW if the
page is non-writable. I think this makes sense.
This commit is contained in:
Andreas Kling 2019-12-02 19:20:09 +01:00
parent f41ae755ec
commit 05c65fb4f1
1 changed files with 1 additions and 1 deletions
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2
Kernel/VM/Region.cpp
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@ -284,7 +284,7 @@ PageFaultResponse Region::handle_fault(const PageFault& fault)
return handle_zero_fault(page_index_in_region); return handle_zero_fault(page_index_in_region);
} }
ASSERT(fault.type() == PageFault::Type::ProtectionViolation); ASSERT(fault.type() == PageFault::Type::ProtectionViolation);
if (fault.access() == PageFault::Access::Write && should_cow(page_index_in_region)) { if (fault.access() == PageFault::Access::Write && is_writable() && should_cow(page_index_in_region)) {
#ifdef PAGE_FAULT_DEBUG #ifdef PAGE_FAULT_DEBUG
dbgprintf("PV(cow) fault in Region{%p}[%u]\n", this, page_index_in_region); dbgprintf("PV(cow) fault in Region{%p}[%u]\n", this, page_index_in_region);
#endif #endif