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linux/debian/patches/patchset-pf/steady/0077-kho-init-new_physxa-phys_bits-to-fix-lockdep.patch

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From cb937c419cee16eb53a09e3c8cc16b675db0214f Mon Sep 17 00:00:00 2001
From: Pasha Tatashin <pasha.tatashin@soleen.com>
Date: Fri, 8 Aug 2025 20:18:02 +0000
Subject: kho: init new_physxa->phys_bits to fix lockdep
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
+++ b/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));