+ kexec-fix-uninitialized-struct-kimage-image-pointer.patch added to mm-nonmm-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: kexec: fix uninitialized struct kimage *image pointer
has been added to the -mm mm-nonmm-unstable branch.  Its filename is
     kexec-fix-uninitialized-struct-kimage-image-pointer.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/kexec-fix-uninitialized-struct-kimage-image-pointer.patch

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

Before you just go and hit "reply", please:
   a) Consider who else should be cc'ed
   b) Prefer to cc a suitable mailing list as well
   c) Ideally: find the original patch on the mailing list and do a
      reply-to-all to that, adding suitable additional cc's

*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days

------------------------------------------------------
From: Qiang Ma <maqianga@uniontech.com>
Subject: kexec: fix uninitialized struct kimage *image pointer
Date: Wed, 26 Nov 2025 16:44:25 +0800

Patch series "kexec: print out debugging message if required for
kexec_load", v3.

Overview:
=========
commit a85ee18c7900 ("kexec_file: print out debugging message if
required") has added general code printing in kexec_file_load(), but not
in kexec_load().

Since kexec_load and kexec_file_load are not triggered simultaneously, we
can unify the debug flag of kexec and kexec_file as kexec_dbg_print.

Next, we need to do some things in this patchset:

1. rename kexec_file_dbg_print to kexec_dbg_print
2. Add KEXEC_DEBUG
3. Initialize kexec_dbg_print for kexec
4. Fix uninitialized struct kimage *image pointer 
5. Set the reset of kexec_dbg_print to kimage_free

Testing:
=========
I did testing on x86_64, arm64 and loongarch.  On x86_64, the printed
messages look like below:

unset CONFIG_KEXEC_FILE:
[   81.502374] kexec: kexec_load: type:0, start:0x23fff7700 head:0x10a4b9002 flags:0x3e0010

set CONFIG_KEXEC_FILE
[   36.774228] kexec_file: kernel: 0000000066c386c8 kernel_size: 0xd78400
[   36.821814] kexec-bzImage64: Loaded purgatory at 0x23fffb000
[   36.821826] kexec-bzImage64: Loaded boot_param, command line and misc at 0x23fff9000 bufsz=0x12d0 memsz=0x2000
[   36.821829] kexec-bzImage64: Loaded 64bit kernel at 0x23d400000 bufsz=0xd73400 memsz=0x2ab7000
[   36.821918] kexec-bzImage64: Loaded initrd at 0x23bd0b000 bufsz=0x16f40a8 memsz=0x16f40a8
[   36.821920] kexec-bzImage64: Final command line is: root=/dev/mapper/test-root crashkernel=auto rd.lvm.lv=test/root
[   36.821925] kexec-bzImage64: E820 memmap:
[   36.821926] kexec-bzImage64: 0000000000000000-000000000009ffff (1)
[   36.821928] kexec-bzImage64: 0000000000100000-0000000000811fff (1)
[   36.821930] kexec-bzImage64: 0000000000812000-0000000000812fff (2)
[   36.821931] kexec-bzImage64: 0000000000813000-00000000bee38fff (1)
[   36.821933] kexec-bzImage64: 00000000bee39000-00000000beec2fff (2)
[   36.821934] kexec-bzImage64: 00000000beec3000-00000000bf8ecfff (1)
[   36.821935] kexec-bzImage64: 00000000bf8ed000-00000000bfb6cfff (2)
[   36.821936] kexec-bzImage64: 00000000bfb6d000-00000000bfb7efff (3)
[   36.821937] kexec-bzImage64: 00000000bfb7f000-00000000bfbfefff (4)
[   36.821938] kexec-bzImage64: 00000000bfbff000-00000000bff7bfff (1)
[   36.821939] kexec-bzImage64: 00000000bff7c000-00000000bfffffff (2)
[   36.821940] kexec-bzImage64: 00000000feffc000-00000000feffffff (2)
[   36.821941] kexec-bzImage64: 00000000ffc00000-00000000ffffffff (2)
[   36.821942] kexec-bzImage64: 0000000100000000-000000023fffffff (1)
[   36.872348] kexec_file: nr_segments = 4
[   36.872356] kexec_file: segment[0]: buf=0x000000005314ece7 bufsz=0x4000 mem=0x23fffb000 memsz=0x5000
[   36.872370] kexec_file: segment[1]: buf=0x000000006e59b143 bufsz=0x12d0 mem=0x23fff9000 memsz=0x2000
[   36.872374] kexec_file: segment[2]: buf=0x00000000eb7b1fc3 bufsz=0xd73400 mem=0x23d400000 memsz=0x2ab7000
[   36.882172] kexec_file: segment[3]: buf=0x000000006af76441 bufsz=0x16f40a8 mem=0x23bd0b000 memsz=0x16f5000
[   36.889113] kexec_file: kexec_file_load: type:0, start:0x23fffb150 head:0x101a2e002 flags:0x8


This patch (of 3):

The image is initialized to NULL.  Then, after calling kimage_alloc_init,
we can directly goto 'out' because at this time, the kimage_free will
determine whether image is a NULL pointer.

This can also prepare for the subsequent patch's kexec_core_dbg_print to
be reset to zero in kimage_free.

Link: https://lkml.kernel.org/r/20251126084427.3222212-1-maqianga@uniontech.com
Link: https://lkml.kernel.org/r/20251126084427.3222212-2-maqianga@uniontech.com
Signed-off-by: Qiang Ma <maqianga@uniontech.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: maqiang <maqianga@uniontech.com>
Cc: kernel test robot <lkp@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 kernel/kexec.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/kernel/kexec.c~kexec-fix-uninitialized-struct-kimage-image-pointer
+++ a/kernel/kexec.c
@@ -95,6 +95,8 @@ static int do_kexec_load(unsigned long e
 	unsigned long i;
 	int ret;
 
+	image = NULL;
+
 	/*
 	 * Because we write directly to the reserved memory region when loading
 	 * crash kernels we need a serialization here to prevent multiple crash
@@ -129,7 +131,7 @@ static int do_kexec_load(unsigned long e
 
 	ret = kimage_alloc_init(&image, entry, nr_segments, segments, flags);
 	if (ret)
-		goto out_unlock;
+		goto out;
 
 	if (flags & KEXEC_PRESERVE_CONTEXT)
 		image->preserve_context = 1;
_

Patches currently in -mm which might be from maqianga@uniontech.com are

kexec-fix-uninitialized-struct-kimage-image-pointer.patch
kexec-add-kexec-flag-to-control-debug-printing.patch
kexec-print-out-debugging-message-if-required-for-kexec_load.patch