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From: Pasha Tatashin <pasha.tatashin@soleen.com>
To: pratyush@kernel.org, jasonmiu@google.com, graf@amazon.com,
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Subject: [PATCH v1 08/32] kho: don't unpreserve memory during abort
Date: Wed, 25 Jun 2025 23:17:55 +0000	[thread overview]
Message-ID: <20250625231838.1897085-9-pasha.tatashin@soleen.com> (raw)
In-Reply-To: <20250625231838.1897085-1-pasha.tatashin@soleen.com>

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 d9e947eac041..7ec9b0826a6e 100644
--- a/kernel/kexec_handover.c
+++ b/kernel/kexec_handover.c
@@ -778,31 +778,12 @@ EXPORT_SYMBOL_GPL(kho_unpreserve_phys);
 
 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)
-- 
2.50.0.727.gbf7dc18ff4-goog



  parent reply	other threads:[~2025-06-25 23:19 UTC|newest]

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-06-25 23:17 [PATCH v1 00/32] Live Update Orchestrator Pasha Tatashin
2025-06-25 23:17 ` [PATCH v1 01/32] kho: init new_physxa->phys_bits to fix lockdep Pasha Tatashin
2025-06-25 23:17 ` [PATCH v1 02/32] kho: mm: Don't allow deferred struct page with KHO Pasha Tatashin
2025-06-25 23:17 ` [PATCH v1 03/32] kho: warn if KHO is disabled due to an error Pasha Tatashin
2025-06-25 23:56   ` Randy Dunlap
2025-07-23 14:39     ` Pasha Tatashin
2025-06-25 23:17 ` [PATCH v1 04/32] kho: allow to drive kho from within kernel Pasha Tatashin
2025-06-25 23:17 ` [PATCH v1 05/32] kho: make debugfs interface optional Pasha Tatashin
2025-06-25 23:17 ` [PATCH v1 06/32] kho: drop notifiers Pasha Tatashin
2025-06-25 23:17 ` [PATCH v1 07/32] kho: add interfaces to unpreserve folios and physical memory ranges Pasha Tatashin
2025-06-25 23:17 ` Pasha Tatashin [this message]
2025-06-25 23:17 ` [PATCH v1 09/32] liveupdate: kho: move to kernel/liveupdate Pasha Tatashin
2025-06-25 23:17 ` [PATCH v1 10/32] liveupdate: luo_core: Live Update Orchestrator Pasha Tatashin
2025-06-25 23:17 ` [PATCH v1 11/32] liveupdate: luo_core: integrate with KHO Pasha Tatashin
2025-06-25 23:17 ` [PATCH v1 12/32] liveupdate: luo_subsystems: add subsystem registration Pasha Tatashin
2025-06-25 23:18 ` [PATCH v1 13/32] liveupdate: luo_subsystems: implement subsystem callbacks Pasha Tatashin
2025-06-25 23:18 ` [PATCH v1 14/32] liveupdate: luo_files: add infrastructure for FDs Pasha Tatashin
2025-06-25 23:18 ` [PATCH v1 15/32] liveupdate: luo_files: implement file systems callbacks Pasha Tatashin
2025-06-25 23:18 ` [PATCH v1 16/32] liveupdate: luo_ioctl: add ioctl interface Pasha Tatashin
2025-06-25 23:18 ` [PATCH v1 17/32] liveupdate: luo_sysfs: add sysfs state monitoring Pasha Tatashin
2025-06-26  0:29   ` Randy Dunlap
2025-07-23 13:53     ` Pasha Tatashin
2025-06-25 23:18 ` [PATCH v1 18/32] reboot: call liveupdate_reboot() before kexec Pasha Tatashin
2025-06-25 23:18 ` [PATCH v1 19/32] liveupdate: luo_files: luo_ioctl: session-based file descriptor tracking Pasha Tatashin
2025-06-25 23:18 ` [PATCH v1 20/32] kho: move kho debugfs directory to liveupdate Pasha Tatashin
2025-06-25 23:18 ` [PATCH v1 21/32] liveupdate: add selftests for subsystems un/registration Pasha Tatashin
2025-06-26  0:06   ` Randy Dunlap
2025-07-23 13:55     ` Pasha Tatashin
2025-06-25 23:18 ` [PATCH v1 22/32] selftests/liveupdate: add subsystem/state tests Pasha Tatashin
2025-06-25 23:18 ` [PATCH v1 23/32] docs: add luo documentation Pasha Tatashin
2025-06-25 23:18 ` [PATCH v1 24/32] MAINTAINERS: add liveupdate entry Pasha Tatashin
2025-06-25 23:18 ` [PATCH v1 25/32] mm: shmem: use SHMEM_F_* flags instead of VM_* flags Pasha Tatashin
2025-06-26 13:00   ` Pratyush Yadav
2025-07-23 14:08     ` Pasha Tatashin
2025-06-25 23:18 ` [PATCH v1 26/32] mm: shmem: allow freezing inode mapping Pasha Tatashin
2025-06-25 23:18 ` [PATCH v1 27/32] mm: shmem: export some functions to internal.h Pasha Tatashin
2025-06-25 23:18 ` [PATCH v1 28/32] luo: allow preserving memfd Pasha Tatashin
2025-06-25 23:18 ` [PATCH v1 29/32] docs: add documentation for memfd preservation via LUO Pasha Tatashin
2025-06-26  2:42   ` Randy Dunlap
2025-06-25 23:18 ` [RFC v1 30/32] tools: introduce libluo Pasha Tatashin
2025-06-25 23:18 ` [RFC v1 31/32] libluo: introduce luoctl Pasha Tatashin
2025-06-25 23:18 ` [RFC v1 32/32] libluo: add tests Pasha Tatashin
2025-06-25 23:26 ` [PATCH v1 00/32] Live Update Orchestrator Benjamin LaHaise
2025-06-25 23:44   ` pasha.tatashin
2025-06-25 23:56     ` Benjamin LaHaise
2025-07-04 17:33     ` Jason Gunthorpe
2025-07-04 21:27       ` Pasha Tatashin

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