The patch titled Subject: kho: init new_physxa->phys_bits to fix lockdep has been added to the -mm mm-hotfixes-unstable branch. Its filename is kho-init-new_physxa-phys_bits-to-fix-lockdep.patch

This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches...

This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------ From: Pasha Tatashin pasha.tatashin@soleen.com Subject: kho: init new_physxa->phys_bits to fix lockdep Date: Fri, 8 Aug 2025 20:18:02 +0000

Patch series "Several KHO Hotfixes".

Three unrelated fixes for Kexec Handover.

This patch (of 3):

Lockdep shows the following warning:

INFO: trying to register non-static key. The code is fine but needs lockdep annotation, or maybe you didn't initialize this object before use? turning off the locking correctness validator.

[<ffffffff810133a6>] dump_stack_lvl+0x66/0xa0 [<ffffffff8136012c>] assign_lock_key+0x10c/0x120 [<ffffffff81358bb4>] register_lock_class+0xf4/0x2f0 [<ffffffff813597ff>] __lock_acquire+0x7f/0x2c40 [<ffffffff81360cb0>] ? __pfx_hlock_conflict+0x10/0x10 [<ffffffff811707be>] ? native_flush_tlb_global+0x8e/0xa0 [<ffffffff8117096e>] ? __flush_tlb_all+0x4e/0xa0 [<ffffffff81172fc2>] ? __kernel_map_pages+0x112/0x140 [<ffffffff813ec327>] ? xa_load_or_alloc+0x67/0xe0 [<ffffffff81359556>] lock_acquire+0xe6/0x280 [<ffffffff813ec327>] ? xa_load_or_alloc+0x67/0xe0 [<ffffffff8100b9e0>] _raw_spin_lock+0x30/0x40 [<ffffffff813ec327>] ? xa_load_or_alloc+0x67/0xe0 [<ffffffff813ec327>] xa_load_or_alloc+0x67/0xe0 [<ffffffff813eb4c0>] kho_preserve_folio+0x90/0x100 [<ffffffff813ebb7f>] __kho_finalize+0xcf/0x400 [<ffffffff813ebef4>] kho_finalize+0x34/0x70

This is becase xa has its own lock, that is not initialized in xa_load_or_alloc.

Modifiy __kho_preserve_order(), to properly call xa_init(&new_physxa->phys_bits);

Link: https://lkml.kernel.org/r/20250808201804.772010-2-pasha.tatashin@soleen.com Fixes: fc33e4b44b27 ("kexec: enable KHO support for memory preservation") Signed-off-by: Pasha Tatashin pasha.tatashin@soleen.com Acked-by: Mike Rapoport (Microsoft) rppt@kernel.org Cc: Alexander Graf graf@amazon.com Cc: Arnd Bergmann arnd@arndb.de Cc: Baoquan He bhe@redhat.com Cc: Changyuan Lyu changyuanl@google.com Cc: Coiby Xu coxu@redhat.com Cc: Dave Vasilevsky dave@vasilevsky.ca Cc: Eric Biggers ebiggers@google.com Cc: Kees Cook kees@kernel.org Cc: Pratyush Yadav pratyush@kernel.org Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

kernel/kexec_handover.c | 28 ++++++++++++++++++++++++---- 1 file changed, 24 insertions(+), 4 deletions(-)

--- a/kernel/kexec_handover.c~kho-init-new_physxa-phys_bits-to-fix-lockdep +++ a/kernel/kexec_handover.c @@ -144,14 +144,34 @@ static int __kho_preserve_order(struct k unsigned int order) { struct kho_mem_phys_bits *bits; - struct kho_mem_phys *physxa; + struct kho_mem_phys *physxa, *new_physxa; const unsigned long pfn_high = pfn >> order;

might_sleep();

- physxa = xa_load_or_alloc(&track->orders, order, sizeof(*physxa)); - if (IS_ERR(physxa)) - return PTR_ERR(physxa); + physxa = xa_load(&track->orders, order); + if (!physxa) { + int err; + + new_physxa = kzalloc(sizeof(*physxa), GFP_KERNEL); + if (!new_physxa) + return -ENOMEM; + + xa_init(&new_physxa->phys_bits); + physxa = xa_cmpxchg(&track->orders, order, NULL, new_physxa, + GFP_KERNEL); + + err = xa_err(physxa); + if (err || physxa) { + xa_destroy(&new_physxa->phys_bits); + kfree(new_physxa); + + if (err) + return err; + } else { + physxa = new_physxa; + } + }

bits = xa_load_or_alloc(&physxa->phys_bits, pfn_high / PRESERVE_BITS, sizeof(*bits)); _

Patches currently in -mm which might be from pasha.tatashin@soleen.com are

kho-init-new_physxa-phys_bits-to-fix-lockdep.patch kho-mm-dont-allow-deferred-struct-page-with-kho.patch kho-warn-if-kho-is-disabled-due-to-an-error.patch