Fix munmap(2) shrink from right logic.
This fixes a rather nasty issue where gcc's garbage collection triggered a munmap call with the effect that it began unmapping huge amounts of kernel data until the system triple faulted.
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4c2a93ea02
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@ -1,6 +1,6 @@
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/*******************************************************************************
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/*******************************************************************************
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Copyright(C) Jonas 'Sortie' Termansen 2011, 2012, 2013.
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Copyright(C) Jonas 'Sortie' Termansen 2011, 2012, 2013, 2015.
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This file is part of Sortix.
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This file is part of Sortix.
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@ -69,6 +69,11 @@ void UnmapMemory(Process* process, uintptr_t addr, size_t size)
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assert(Page::IsAligned(size));
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assert(Page::IsAligned(size));
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assert(process == CurrentProcess());
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assert(process == CurrentProcess());
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if ( UINTPTR_MAX - addr < size )
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size = Page::AlignDown(UINTPTR_MAX - addr);
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if ( !size )
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return;
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struct segment unmap_segment;
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struct segment unmap_segment;
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unmap_segment.addr = addr;
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unmap_segment.addr = addr;
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unmap_segment.size = size;
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unmap_segment.size = size;
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@ -77,7 +82,7 @@ void UnmapMemory(Process* process, uintptr_t addr, size_t size)
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&unmap_segment) )
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&unmap_segment) )
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{
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{
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// Delete the segment if covered entirely by our request.
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// Delete the segment if covered entirely by our request.
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if ( addr <= conflict->addr && conflict->addr + conflict->size - addr <= size )
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if ( addr <= conflict->addr && conflict->addr + conflict->size <= addr + size )
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{
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{
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uintptr_t conflict_offset = (uintptr_t) conflict - (uintptr_t) process->segments;
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uintptr_t conflict_offset = (uintptr_t) conflict - (uintptr_t) process->segments;
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size_t conflict_index = conflict_offset / sizeof(struct segment);
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size_t conflict_index = conflict_offset / sizeof(struct segment);
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@ -122,11 +127,11 @@ void UnmapMemory(Process* process, uintptr_t addr, size_t size)
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}
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}
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// Delete the part of the segment covered partially from the right.
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// Delete the part of the segment covered partially from the right.
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if ( conflict->addr + size <= addr + size )
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if ( conflict->addr <= addr + size )
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{
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{
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Memory::UnmapRange(addr, addr + conflict->size + conflict->addr, PAGE_USAGE_USER_SPACE);
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Memory::UnmapRange(addr, conflict->addr + conflict->size - addr, PAGE_USAGE_USER_SPACE);
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Memory::Flush();
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Memory::Flush();
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conflict->size -= conflict->size + conflict->addr;
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conflict->size -= conflict->addr + conflict->size - addr;
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continue;
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continue;
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}
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}
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}
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}
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