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Kernel: Make sure the offset stays the same when using mremap()

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When using mmap() on a file with a non-zero offset subsequent
calls to mremap() would incorrectly reset the offset to zero.
This commit is contained in:
Gunnar Beutner 2021-04-13 19:27:49 +02:00 • committed by Andreas Kling
parent 341b44b6f7
commit 2d91761cf6
1 changed files with 2 additions and 1 deletions
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3
Kernel/Syscalls/mmap.cpp
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@ -566,6 +566,7 @@ KResultOr<FlatPtr> Process::sys$mremap(Userspace<const Syscall::SC_mremap_params
auto range = old_region->range();
auto old_name = old_region->name();
auto old_prot = region_access_flags_to_prot(old_region->access());
auto old_offset = old_region->offset_in_vmobject();
NonnullRefPtr inode = static_cast<SharedInodeVMObject&>(old_region->vmobject()).inode();
// Unmap without deallocating the VM range since we're going to reuse it.
@ -575,7 +576,7 @@ KResultOr<FlatPtr> Process::sys$mremap(Userspace<const Syscall::SC_mremap_params
auto new_vmobject = PrivateInodeVMObject::create_with_inode(inode);
auto new_region_or_error = space().allocate_region_with_vmobject(range, new_vmobject, 0, old_name, old_prot, false);
auto new_region_or_error = space().allocate_region_with_vmobject(range, new_vmobject, old_offset, old_name, old_prot, false);
if (new_region_or_error.is_error())
return new_region_or_error.error().error();
auto& new_region = *new_region_or_error.value();