RGBCube/serenity
1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-05-31 18:28:12 +00:00
Code Issues Activity Actions

Kernel: Make Region splitting OOM-safe

Browse source 
Region allocation failures during splitting are now propagated all the
way out to where we can return ENOMEM for them.
This commit is contained in:
Andreas Kling 2021-07-11 18:51:54 +02:00
parent cac557eee0
commit cd7a49b90d
3 changed files with 40 additions and 16 deletions
Download patch file Download diff file Expand all files Collapse all files

22
Kernel/Syscalls/mmap.cpp
View file

@ -341,10 +341,16 @@ KResultOr<FlatPtr> Process::sys$mprotect(Userspace<void*> addr, size_t size, int
// This vector is the region(s) adjacent to our range.
// We need to allocate a new region for the range we wanted to change permission bits on.
auto adjacent_regions = space().split_region_around_range(*region, range_to_mprotect);
auto adjacent_regions_or_error = space().try_split_region_around_range(*region, range_to_mprotect);
if (adjacent_regions_or_error.is_error())
return adjacent_regions_or_error.error();
auto& adjacent_regions = adjacent_regions_or_error.value();
size_t new_range_offset_in_vmobject = region->offset_in_vmobject() + (range_to_mprotect.base().get() - region->range().base().get());
auto& new_region = space().allocate_split_region(*region, range_to_mprotect, new_range_offset_in_vmobject);
auto new_region_or_error = space().try_allocate_split_region(*region, range_to_mprotect, new_range_offset_in_vmobject);
if (new_region_or_error.is_error())
return new_region_or_error.error();
auto& new_region = *new_region_or_error.value();
new_region.set_readable(prot & PROT_READ);
new_region.set_writable(prot & PROT_WRITE);
new_region.set_executable(prot & PROT_EXEC);
@ -399,12 +405,20 @@ KResultOr<FlatPtr> Process::sys$mprotect(Userspace<void*> addr, size_t size, int
// This vector is the region(s) adjacent to our range.
// We need to allocate a new region for the range we wanted to change permission bits on.
auto adjacent_regions = space().split_region_around_range(*old_region, intersection_to_mprotect);
auto adjacent_regions_or_error = space().try_split_region_around_range(*old_region, intersection_to_mprotect);
if (adjacent_regions_or_error.is_error())
return adjacent_regions_or_error.error();
auto& adjacent_regions = adjacent_regions_or_error.value();
// there should only be one
VERIFY(adjacent_regions.size() == 1);
size_t new_range_offset_in_vmobject = old_region->offset_in_vmobject() + (intersection_to_mprotect.base().get() - old_region->range().base().get());
auto& new_region = space().allocate_split_region(*region, intersection_to_mprotect, new_range_offset_in_vmobject);
auto new_region_or_error = space().try_allocate_split_region(*region, intersection_to_mprotect, new_range_offset_in_vmobject);
if (new_region_or_error.is_error())
return new_region_or_error.error();
auto& new_region = *new_region_or_error.value();
new_region.set_readable(prot & PROT_READ);
new_region.set_writable(prot & PROT_WRITE);
new_region.set_executable(prot & PROT_EXEC);