KHO allows clients to preserve memory regions at any point before the
KHO state is finalized. The finalization process itself involves KHO
performing its own actions, such as serializing the overall
preserved memory map.

If this finalization process is aborted, the current implementation
destroys KHO's internal memory tracking structures
(`kho_out.ser.track.orders`). This behavior effectively unpreserves
all memory from KHO's perspective, regardless of whether those
preservations were made by clients before the finalization attempt
or by KHO itself during finalization.

This premature unpreservation is incorrect. An abort of the
finalization process should only undo actions taken by KHO as part of
that specific finalization attempt. Individual memory regions
preserved by clients prior to finalization should remain preserved,
as their lifecycle is managed by the clients themselves. These
clients might still need to call kho_unpreserve_folio() or
kho_unpreserve_phys() based on their own logic, even after a KHO
finalization attempt is aborted.

Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
---
 kernel/kexec_handover.c | 21 +--------------------
 1 file changed, 1 insertion(+), 20 deletions(-)

diff --git a/kernel/kexec_handover.c b/kernel/kexec_handover.c
index c514b300ebe6..3adf86c7c2db 100644
--- a/kernel/kexec_handover.c
+++ b/kernel/kexec_handover.c
@@ -1118,31 +1118,12 @@ EXPORT_SYMBOL_GPL(kho_restore_vmalloc);
 
 static int __kho_abort(void)
 {
-	int err = 0;
-	unsigned long order;
-	struct kho_mem_phys *physxa;
-
-	xa_for_each(&kho_out.track.orders, order, physxa) {
-		struct kho_mem_phys_bits *bits;
-		unsigned long phys;
-
-		xa_for_each(&physxa->phys_bits, phys, bits)
-			kfree(bits);
-
-		xa_destroy(&physxa->phys_bits);
-		kfree(physxa);
-	}
-	xa_destroy(&kho_out.track.orders);
-
 	if (kho_out.preserved_mem_map) {
 		kho_mem_ser_free(kho_out.preserved_mem_map);
 		kho_out.preserved_mem_map = NULL;
 	}
 
-	if (err)
-		pr_err("Failed to abort KHO finalization: %d\n", err);
-
-	return err;
+	return 0;
 }
 
 int kho_abort(void)
-- 
2.51.1.930.gacf6e81ea2-goog

On Sat, Nov 01 2025, Pasha Tatashin wrote:

> KHO allows clients to preserve memory regions at any point before the
> KHO state is finalized. The finalization process itself involves KHO
> performing its own actions, such as serializing the overall
> preserved memory map.
>
> If this finalization process is aborted, the current implementation
> destroys KHO's internal memory tracking structures
> (`kho_out.ser.track.orders`). This behavior effectively unpreserves
> all memory from KHO's perspective, regardless of whether those
> preservations were made by clients before the finalization attempt
> or by KHO itself during finalization.
>
> This premature unpreservation is incorrect. An abort of the
> finalization process should only undo actions taken by KHO as part of
> that specific finalization attempt. Individual memory regions
> preserved by clients prior to finalization should remain preserved,
> as their lifecycle is managed by the clients themselves. These
> clients might still need to call kho_unpreserve_folio() or
> kho_unpreserve_phys() based on their own logic, even after a KHO
> finalization attempt is aborted.
>
> Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>

Reviewed-by: Pratyush Yadav <pratyush@kernel.org>

[...]

-- 
Regards,
Pratyush Yadav