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| author | Pratyush Yadav (Google) <pratyush@kernel.org> | 2026-07-27 17:02:39 +0200 |
|---|---|---|
| committer | Mike Rapoport (Microsoft) <rppt@kernel.org> | 2026-07-29 09:11:15 +0300 |
| commit | 3a0b8fa2eb36afc88b62a95f33f0c77c71fa5ded (patch) | |
| tree | 0d365b8437bcfe321ecd2722743e5ac1912da8a9 | |
| parent | 5c4a03afcb21783987ffc64562b76ddd5a21b12b (diff) | |
| download | linux-next-3a0b8fa2eb36afc88b62a95f33f0c77c71fa5ded.tar.gz linux-next-3a0b8fa2eb36afc88b62a95f33f0c77c71fa5ded.zip | |
kho: fix size calculation in kho_preserved_memory_reserve()
kho_preserved_memory_reserve() calculates the size of a preservation by
doing 1 << (order + PAGE_SHIFT). Since the '1' is a 32-bit integer, it
can only be shifted by 31. That is, it will only work for preservations
up to 2 GiB. Larger preservations will trigger undefined behaviour.
While preservations larger than 2 GiB can't be obtained via folios
currently, they can be obtained via kho_preserve_pages().
For example, memblock reserve_mem uses kho_preserve_pages().
Reservations larger than 2 GiB are valid and will trigger this bug if
properly aligned.
Fix it by using 1UL for shifting.
Fixes: fc33e4b44b27 ("kexec: enable KHO support for memory preservation")
Reported-by: Sashiko <sashiko-bot@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: Pratyush Yadav (Google) <pratyush@kernel.org>
Link: https://patch.msgid.link/20260727150240.889555-1-pratyush@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
| -rw-r--r-- | kernel/liveupdate/kexec_handover.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/liveupdate/kexec_handover.c b/kernel/liveupdate/kexec_handover.c index 175c08a6e41e..6fad9152387a 100644 --- a/kernel/liveupdate/kexec_handover.c +++ b/kernel/liveupdate/kexec_handover.c @@ -501,7 +501,7 @@ static int __init kho_preserved_memory_reserve(phys_addr_t phys, struct page *page; u64 sz; - sz = 1 << (order + PAGE_SHIFT); + sz = 1UL << (order + PAGE_SHIFT); page = kho_get_preserved_page(phys, order); /* Reserve the memory preserved in KHO in memblock */ |