Re: [linux-next:master 4972/5926] kernel/kexec_handover_debug.c:16:18: error: use of undeclared identifier 'kho_scratch_cnt'

[Pasha Tatashin <pasha.tatashin@soleen.com>]

The fix looks like this:
diff --git a/kernel/kexec_handover.c b/kernel/kexec_handover.c
index de4466b47455..2a8c20c238a8 100644
--- a/kernel/kexec_handover.c
+++ b/kernel/kexec_handover.c
@@ -477,8 +477,8 @@ static void __init kho_mem_deserialize(const void *fdt)
  * area for early allocations that happen before page allocator is
  * initialized.
  */
-static struct kho_scratch *kho_scratch;
-static unsigned int kho_scratch_cnt;
+struct kho_scratch *kho_scratch;
+unsigned int kho_scratch_cnt;

 /*
  * The scratch areas are scaled by default as percent of memory allocated from
diff --git a/kernel/kexec_handover_internal.h b/kernel/kexec_handover_internal.h
index 05e9720ba7b9..3c3c7148ceed 100644
--- a/kernel/kexec_handover_internal.h
+++ b/kernel/kexec_handover_internal.h
@@ -2,8 +2,12 @@
 #ifndef LINUX_KEXEC_HANDOVER_INTERNAL_H
 #define LINUX_KEXEC_HANDOVER_INTERNAL_H

+#include <linux/kexec_handover.h>
 #include <linux/types.h>

+extern struct kho_scratch *kho_scratch;
+extern unsigned int kho_scratch_cnt;
+
 #ifdef CONFIG_KEXEC_HANDOVER_DEBUG
 bool kho_scratch_overlap(phys_addr_t phys, size_t size);
 #else

Andrew, Mike, do you want me to resend the "[PATCH v3 0/3] KHO: kfence
+ KHO memory corruption fix" series with the fix included?

On Tue, Nov 4, 2025 at 12:32 PM Pasha Tatashin
<pasha.tatashin@soleen.com> wrote:
>
> Eh, "kho: make debugfs interface optional" makes this variable external.
>
> Let me see how to fix this quickly.
>
> On Tue, Nov 4, 2025 at 10:38 AM Mike Rapoport <rppt@kernel.org> wrote:
> >
> > (adding Pasha)
> >
> > On Tue, Nov 04, 2025 at 10:48:31PM +0800, kernel test robot wrote:
> > > Hi Mike,
> > >
> > > First bad commit (maybe != root cause):
> > >
> > > tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
> > > head:   17490bd0527f59d841168457b245581f314b5fa0
> > > commit: 8c211175c3abcebb8bffce8095d78d193e482105 [4972/5926] liveupdate-kho-warn-and-fail-on-metadata-or-preserved-memory-in-scratch-area-fix
> > > config: x86_64-randconfig-071-20251104 (https://download.01.org/0day-ci/archive/20251104/202511042251.paO6f5BZ-lkp@intel.com/config)
> > > compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261)
> > > reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251104/202511042251.paO6f5BZ-lkp@intel.com/reproduce)
> > >
> > > If you fix the issue in a separate patch/commit (i.e. not just a new version of
> > > the same patch/commit), kindly add following tags
> > > | Reported-by: kernel test robot <lkp@intel.com>
> > > | Closes: https://lore.kernel.org/oe-kbuild-all/202511042251.paO6f5BZ-lkp@intel.com/
> > >
> > > All errors (new ones prefixed by >>):
> > >
> > > >> kernel/kexec_handover_debug.c:16:18: error: use of undeclared identifier 'kho_scratch_cnt'
> > >       16 |         for (i = 0; i < kho_scratch_cnt; i++) {
> > >          |                         ^
> > > >> kernel/kexec_handover_debug.c:17:19: error: use of undeclared identifier 'kho_scratch'
> > >       17 |                 scratch_start = kho_scratch[i].addr;
> > >          |                                 ^
> > >    kernel/kexec_handover_debug.c:18:17: error: use of undeclared identifier 'kho_scratch'
> > >       18 |                 scratch_end = kho_scratch[i].addr + kho_scratch[i].size;
> > >          |                               ^
> > >    kernel/kexec_handover_debug.c:18:39: error: use of undeclared identifier 'kho_scratch'
> > >       18 |                 scratch_end = kho_scratch[i].addr + kho_scratch[i].size;
> > >          |                                                     ^
> > >    4 errors generated.
> > >
> > >
> > > vim +/kho_scratch_cnt +16 kernel/kexec_handover_debug.c
> > >
> > > 4039a00022d42a Pasha Tatashin 2025-10-20  10
> > > 4039a00022d42a Pasha Tatashin 2025-10-20  11  bool kho_scratch_overlap(phys_addr_t phys, size_t size)
> > > 4039a00022d42a Pasha Tatashin 2025-10-20  12  {
> > > 4039a00022d42a Pasha Tatashin 2025-10-20  13          phys_addr_t scratch_start, scratch_end;
> > > 4039a00022d42a Pasha Tatashin 2025-10-20  14          unsigned int i;
> > > 4039a00022d42a Pasha Tatashin 2025-10-20  15
> > > 4039a00022d42a Pasha Tatashin 2025-10-20 @16          for (i = 0; i < kho_scratch_cnt; i++) {
> > > 4039a00022d42a Pasha Tatashin 2025-10-20 @17                  scratch_start = kho_scratch[i].addr;
> > >
> > > :::::: The code at line 16 was first introduced by commit
> > > :::::: 4039a00022d42ac3d68b2eea63066bc9f7ef89ce kho: warn and fail on metadata or preserved memory in scratch area
> > >
> > > :::::: TO: Pasha Tatashin <pasha.tatashin@soleen.com>
> > > :::::: CC: Andrew Morton <akpm@linux-foundation.org>
> > >
> > > --
> > > 0-DAY CI Kernel Test Service
> > > https://github.com/intel/lkp-tests/wiki
> >
> > --
> > Sincerely yours,
> > Mike.