kho: warn if KHO is disabled due to an error

During boot scratch area is allocated based on command line parameters or
auto calculated.  However, scratch area may fail to allocate, and in that
case KHO is disabled.  Currently, no warning is printed that KHO is
disabled, which makes it confusing for the end user to figure out why KHO
is not available.  Add the missing warning message.

Link: https://lkml.kernel.org/r/20250808201804.772010-4-pasha.tatashin@soleen.com
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Acked-by: Pratyush Yadav <pratyush@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: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/kernel/kexec_handover.c b/kernel/kexec_handover.c
index 65145972d6d6ad6f5cd7e97bb34228e7ed488a4a..ecd1ac210dbd74edc83f9cd4c5d4483e14399222 100644 (file)
--- a/kernel/kexec_handover.c
+++ b/kernel/kexec_handover.c
@@ -564,6 +564,7 @@ err_free_scratch_areas:
 err_free_scratch_desc:
        memblock_free(kho_scratch, kho_scratch_cnt * sizeof(*kho_scratch));
 err_disable_kho:
+       pr_warn("Failed to reserve scratch area, disabling kexec handover\n");
        kho_enable = false;
 }