linux-kernel - Re: [PATCH v2 1/2] kho: fix missing early_memunmap() call in kho

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Message-ID: <2vxzy0kzr5ha.fsf@kernel.org>
Date: Wed, 11 Feb 2026 10:31:45 +0100
From: Pratyush Yadav <pratyush@...nel.org>
To: ranxiaokai627@....com
Cc: graf@...zon.com,  rppt@...nel.org,  pasha.tatashin@...een.com,
  pratyush@...nel.org,  akpm@...ux-foundation.org,
  kexec@...ts.infradead.org,  linux-mm@...ck.org,
  linux-kernel@...r.kernel.org,  ran.xiaokai@....com.cn
Subject: Re: [PATCH v2 1/2] kho: fix missing early_memunmap() call in
 kho_populate()

Hi Ran,

On Wed, Feb 11 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()")
> Reviewed-by: Pratyush Yadav <pratyush@...nel.org>
> Signed-off-by: Ran Xiaokai <ran.xiaokai@....com.cn>
> ---
>  kernel/liveupdate/kexec_handover.c | 12 +++++++-----
>  1 file changed, 7 insertions(+), 5 deletions(-)
>
> diff --git a/kernel/liveupdate/kexec_handover.c b/kernel/liveupdate/kexec_handover.c
> index fb3a7b67676e..3c705b08a489 100644
> --- a/kernel/liveupdate/kexec_handover.c
> +++ b/kernel/liveupdate/kexec_handover.c
> @@ -1463,13 +1463,14 @@ 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;
> +	bool populated = false;
>  	int err;
>  
>  	/* Validate the input FDT */
>  	fdt = early_memremap(fdt_phys, fdt_len);
>  	if (!fdt) {
>  		pr_warn("setup: failed to memremap FDT (0x%llx)\n", fdt_phys);
> -		goto err_report;
> +		goto report;
>  	}
>  	err = fdt_check_header(fdt);
>  	if (err) {
> @@ -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 = true;
> +	pr_info("found kexec handover data.\n");
>  
>  err_unmap_scratch:
>  	early_memunmap(scratch, scratch_len);
>  err_unmap_fdt:
>  	early_memunmap(fdt, fdt_len);

I meant to say all these labels should be renamed, not just err_report.
So "err_unmap_scratch" should be "unmap_scratch", and "err_unmap_fdt"
should be "unmap_fdt".

> -err_report:
> -	pr_warn("disabling KHO revival\n");
> +report:
> +	if (!populated)
> +		pr_warn("disabling KHO revival\n");
>  }
>  
>  /* Helper functions for kexec_file_load */

-- 
Regards,
Pratyush Yadav