kho: warn if KHO is disabled due to an error

commit 44958f2025ed3f29fc3e93bb1f6c16121d7847ad upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/kernel/kexec_handover.c b/kernel/kexec_handover.c
index e4e9a4b4062590d7d1977da1881e8e036d8d1837..e640d3eb3430985749a54d753f8bb970e5f112f2 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;
 }