linux-kernel - Re: [PATCH -next 1/2] kho: fix missing early_memunmap() call in kho

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Message-ID: <20260211012346.208225-1-ranxiaokai627@163.com>
Date: Wed, 11 Feb 2026 01:23:46 +0000
From: ranxiaokai627@....com
To: pratyush@...nel.org
Cc: akpm@...ux-foundation.org,
	graf@...zon.com,
	kexec@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	linux-mm@...ck.org,
	pasha.tatashin@...een.com,
	ran.xiaokai@....com.cn,
	ranxiaokai627@....com,
	rppt@...nel.org,
	stable@...r.kernel.org
Subject: Re: [PATCH -next 1/2] kho: fix missing early_memunmap() call in kho_populate()

>Hi Ran,
>
>Thanks for the fix.
>
>On Fri, Feb 06 2026, ranxiaokai627@....com wrote:
>
>> From: Ran Xiaokai <ran.xiaokai@....com.cn>
>>
>> kho_populate() returns without calling early_memunmap() on success
>> path, this will cause early ioremap virtual address space leak.
>>
>> Fixes: b50634c5e84a ("kho: cleanup error handling in kho_populate()")
>> Signed-off-by: Ran Xiaokai <ran.xiaokai@....com.cn>
>> ---
>>
>> b50634c5e84a ("kho: cleanup error handling in kho_populate()")
>> has not landed in upstream, so
>> Cc: <stable@...r.kernel.org> is unnecessary?
>>
>>  kernel/liveupdate/kexec_handover.c | 8 +++++---
>>  1 file changed, 5 insertions(+), 3 deletions(-)
>>
>> diff --git a/kernel/liveupdate/kexec_handover.c b/kernel/liveupdate/kexec_handover.c
>> index fb3a7b67676e..76b714db175d 100644
>> --- a/kernel/liveupdate/kexec_handover.c
>> +++ b/kernel/liveupdate/kexec_handover.c
>> @@ -1463,6 +1463,7 @@ void __init kho_populate(phys_addr_t fdt_phys, u64 fdt_len,
>>  	struct kho_scratch *scratch = NULL;
>>  	phys_addr_t mem_map_phys;
>>  	void *fdt = NULL;
>> +	int populated = 0;
>
>Nit: Please use a bool and true/false. I think it reads much nicer.

yes.

>>  	int err;
>>  
>>  	/* Validate the input FDT */
>> @@ -1529,16 +1530,17 @@ void __init kho_populate(phys_addr_t fdt_phys, u64 fdt_len,
>>  	kho_in.scratch_phys = scratch_phys;
>>  	kho_in.mem_map_phys = mem_map_phys;
>>  	kho_scratch_cnt = scratch_cnt;
>> -	pr_info("found kexec handover data.\n");
>>  
>> -	return;
>> +	populated = 1;
>> +	pr_info("found kexec handover data.\n");
>>  
>>  err_unmap_scratch:
>>  	early_memunmap(scratch, scratch_len);
>>  err_unmap_fdt:
>>  	early_memunmap(fdt, fdt_len);
>>  err_report:
>
>Nit: now that this code can be reached by non-error paths, we should
>re-name the labels. I think dropping the "err_" prefix should be enough.

Thanks for your review.
Very helpful suggestion. I will send a v2.

>With these fixed,
>
>Reviewed-by: Pratyush Yadav <pratyush@...nel.org>
>
>> -	pr_warn("disabling KHO revival\n");
>> +	if (!populated)
>> +		pr_warn("disabling KHO revival\n");
>>  }
>>  
>>  /* Helper functions for kexec_file_load */