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Kernel: Handle OOM when adding memory regions to Spaces :^)

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This commit is contained in:
Idan Horowitz 2021-07-15 01:18:00 +03:00 committed by Andreas Kling
parent e94dfb7355
commit be475cd6a8
Notes: sideshowbarker 2024-07-18 09:00:44 +09:00 
Author: https://github.com/IdanHo
Commit: https://github.com/SerenityOS/serenity/commit/be475cd6a83
Pull-request: https://github.com/SerenityOS/serenity/pull/8758
3 changed files with 30 additions and 18 deletions
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9
Kernel/Syscalls/fork.cpp
View File

@ -102,8 +102,13 @@ KResultOr<FlatPtr> Process::sys$fork(RegisterState& regs)
return ENOMEM;
}
auto& child_region = child->space().add_region(region_clone.release_nonnull());
child_region.map(child->space().page_directory(), ShouldFlushTLB::No);
auto* child_region = child->space().add_region(region_clone.release_nonnull());
if (!child_region) {
dbgln("fork: Cannot add region, insufficient memory");
// TODO: tear down new process?
return ENOMEM;
}
child_region->map(child->space().page_directory(), ShouldFlushTLB::No);
if (region == m_master_tls_region.unsafe_ptr())
child->m_master_tls_region = child_region;

37
Kernel/VM/Space.cpp
View File

@ -156,16 +156,18 @@ KResultOr<Region*> Space::try_allocate_split_region(Region const& source_region,
m_process, range, source_region.vmobject(), offset_in_vmobject, KString::try_create(source_region.name()), source_region.access(), source_region.is_cacheable() ? Region::Cacheable::Yes : Region::Cacheable::No, source_region.is_shared());
if (!new_region)
return ENOMEM;
auto& region = add_region(new_region.release_nonnull());
region.set_syscall_region(source_region.is_syscall_region());
region.set_mmap(source_region.is_mmap());
region.set_stack(source_region.is_stack());
auto* region = add_region(new_region.release_nonnull());
if (!region)
return ENOMEM;
region->set_syscall_region(source_region.is_syscall_region());
region->set_mmap(source_region.is_mmap());
region->set_stack(source_region.is_stack());
size_t page_offset_in_source_region = (offset_in_vmobject - source_region.offset_in_vmobject()) / PAGE_SIZE;
for (size_t i = 0; i < region.page_count(); ++i) {
for (size_t i = 0; i < region->page_count(); ++i) {
if (source_region.should_cow(page_offset_in_source_region + i))
region.set_should_cow(i, true);
region->set_should_cow(i, true);
}
return &region;
return region;
}
KResultOr<Region*> Space::allocate_region(Range const& range, StringView name, int prot, AllocationStrategy strategy)
@ -179,7 +181,10 @@ KResultOr<Region*> Space::allocate_region(Range const& range, StringView name, i
return ENOMEM;
if (!region->map(page_directory()))
return ENOMEM;
return &add_region(region.release_nonnull());
auto* added_region = add_region(region.release_nonnull());
if (!added_region)
return ENOMEM;
return added_region;
}
KResultOr<Region*> Space::allocate_region_with_vmobject(Range const& range, NonnullRefPtr<VMObject> vmobject, size_t offset_in_vmobject, StringView name, int prot, bool shared)
@ -202,14 +207,16 @@ KResultOr<Region*> Space::allocate_region_with_vmobject(Range const& range, Nonn
auto region = Region::try_create_user_accessible(m_process, range, move(vmobject), offset_in_vmobject, KString::try_create(name), prot_to_region_access_flags(prot), Region::Cacheable::Yes, shared);
if (!region) {
dbgln("allocate_region_with_vmobject: Unable to allocate Region");
return nullptr;
return ENOMEM;
}
auto& region_ref = add_region(region.release_nonnull());
if (!region_ref.map(page_directory())) {
auto* added_region = add_region(region.release_nonnull());
if (!added_region)
return ENOMEM;
if (!added_region->map(page_directory())) {
// FIXME: What is an appropriate error code here, really?
return ENOMEM;
}
return &region_ref;
return added_region;
}
bool Space::deallocate_region(Region& region)
@ -284,12 +291,12 @@ Vector<Region*> Space::find_regions_intersecting(const Range& range)
return regions;
}
Region& Space::add_region(NonnullOwnPtr<Region> region)
Region* Space::add_region(NonnullOwnPtr<Region> region)
{
auto* ptr = region.ptr();
ScopedSpinLock lock(m_lock);
m_regions.insert(region->vaddr().get(), move(region));
return *ptr;
auto success = m_regions.try_insert(region->vaddr().get(), move(region));
return success ? ptr : nullptr;
}
// Carve out a virtual address range from a region and return the two regions on either side

2
Kernel/VM/Space.h
View File

@ -24,7 +24,7 @@ public:
PageDirectory& page_directory() { return *m_page_directory; }
const PageDirectory& page_directory() const { return *m_page_directory; }
Region& add_region(NonnullOwnPtr<Region>);
Region* add_region(NonnullOwnPtr<Region>);
size_t region_count() const { return m_regions.size(); }