linux-kernel - Re: [PATCH] kexec: Fix uninitialized struct kimage *image pointer

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Message-ID: <C2FBF39E1F0503D4+8030be33-fd88-4f18-b631-a4fecaf62c5a@uniontech.com>
Date: Mon, 15 Dec 2025 12:41:51 +0800
From: Qiang Ma <maqianga@...ontech.com>
To: Baoquan He <bhe@...hat.com>
Cc: akpm@...ux-foundation.org, kexec@...ts.infradead.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH] kexec: Fix uninitialized struct kimage *image pointer


在 2025/12/15 09:18, Baoquan He 写道:
> On 12/14/25 at 07:35pm, Qiang Ma wrote:
>> 在 2025/12/12 18:53, Baoquan He 写道:
>>> On 12/12/25 at 03:16pm, Qiang Ma wrote:
>>>> 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.
>>> Rechecked the code flow, in kimage_alloc_init(), if anything wrong, the
>>> allocated memory are all freed via out_free_control_pages and
>>> out_free_image accordingly, any place missed? If no, I think the current
>>> code is correctly handled.
>> I rechecked the code and found no omissions.
> Hmm, my bad, I didn't say my question clearly. I checked code, didn't
> find anything wrong in the current code. In kimage_alloc_init(), the
> allocated memory are all freed on failure, no memory leaked. Means you
> are fixing correct code.
Oh, I see. I recalled that this fix was in preparation for patch
"kexec: add kexec flag to control debug printing" for kexec_dbg_print
to be reset to false in kimage_free.

In that case, I don't think this patch should be posted separately.
>
>>>> Signed-off-by: Qiang Ma <maqianga@...ontech.com>
>>>> ---
>>>>    kernel/kexec.c | 4 +++-
>>>>    1 file changed, 3 insertions(+), 1 deletion(-)
>>> Acked-by: Baoquan He <bhe@...hat.com>
>>>
>>>> diff --git a/kernel/kexec.c b/kernel/kexec.c
>>>> index 28008e3d462e..9bb1f2b6b268 100644
>>>> --- a/kernel/kexec.c
>>>> +++ b/kernel/kexec.c
>>>> @@ -95,6 +95,8 @@ static int do_kexec_load(unsigned long entry, unsigned long nr_segments,
>>>>    	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 entry, unsigned long nr_segments,
>>>>    	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;
>>>> -- 
>>>> 2.20.1
>>>>
>