github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-07-29 02:31:27 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

arm64/mm: Check the requested PFN range during memory removal

Browse Source 
prevent_memory_remove_notifier() advances pfn while scanning the requested
range for early memory. When the loop completes, pfn is at or beyond
end_pfn. Passing it to can_unmap_without_split() therefore checks a range
after the one being offlined.

Consequently, a valid request can be rejected based on the following
range, while a request that would split a leaf mapping can be accepted if
the shifted range can be unmapped without a split. This was observed with
CXL DAX memory, where the final memory block was incorrectly allowed to
be offlined.

Pass arg->start_pfn into can_unmap_without_split() so it checks the
requested range.

Fixes: 95a58852b0 ("arm64/mm: Reject memory removal that splits a kernel leaf mapping")
Signed-off-by: Richard Cheng <icheng@nvidia.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
This commit is contained in:
Richard Cheng 2026-07-21 18:00:26 +08:00 committed by Will Deacon
parent b877075d0b
commit 285f90a4d1
1 changed files with 1 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/arm64/mm/mmu.c
View File

@ -2194,7 +2194,7 @@ static int prevent_memory_remove_notifier(struct notifier_block *nb,
}
}
if (!can_unmap_without_split(pfn, arg->nr_pages))
if (!can_unmap_without_split(arg->start_pfn, arg->nr_pages))
return NOTIFY_BAD;
return NOTIFY_OK;