Received-SPF: pass (google.com: domain of linux-kernel+bounces-206045-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:4601:e00::3 as permitted sender) client-ip=2604:1380:4601:e00::3;
Date: Fri, 7 Jun 2024 20:27:21 +0800
From: Coiby Xu <coxu@redhat.com>
To: Baoquan He <bhe@redhat.com>
Cc: kexec@lists.infradead.org, Ondrej Kozina <okozina@redhat.com>, 
	Milan Broz <gmazyland@gmail.com>, Thomas Staudt <tstaudt@de.ibm.com>, 
	Daniel P =?utf-8?B?LiBCZXJyYW5nw6k=?= <berrange@redhat.com>, Kairui Song <ryncsn@gmail.com>, 
	Jan Pazdziora <jpazdziora@redhat.com>, Pingfan Liu <kernelfans@gmail.com>, 
	Dave Young <dyoung@redhat.com>, linux-kernel@vger.kernel.org, x86@kernel.org, 
	Dave Hansen <dave.hansen@intel.com>, Vitaly Kuznetsov <vkuznets@redhat.com>, 
	Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>, 
	Dave Hansen <dave.hansen@linux.intel.com>, "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH v4 6/7] x86/crash: pass dm crypt keys to kdump kernel
Message-ID: <qzyj55v7umimqgq265ya4jds4kvzabeq7wg3eah6ppc3a6eygh@4fid6x2vp35d>
References: <20240523050451.788754-1-coxu@redhat.com>
 <20240523050451.788754-7-coxu@redhat.com>
 <ZmLZkvYRJvdRVqwr@MiWiFi-R3L-srv>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii; format=flowed
Content-Disposition: inline
In-Reply-To: <ZmLZkvYRJvdRVqwr@MiWiFi-R3L-srv>

On Fri, Jun 07, 2024 at 05:57:38PM +0800, Baoquan He wrote:
>On 05/23/24 at 01:04pm, Coiby Xu wrote:
>> 1st kernel will build up the kernel command parameter dmcryptkeys as
>> similar to elfcorehdr to pass the memory address of the stored info of
>> dm crypt key to kdump kernel.
>>
>> Signed-off-by: Coiby Xu <coxu@redhat.com>
>> ---
>>  arch/x86/kernel/crash.c           | 15 ++++++++++++++-
>>  arch/x86/kernel/kexec-bzimage64.c |  7 +++++++
>>  2 files changed, 21 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
>> index f06501445cd9..74b3844ae53c 100644
>> --- a/arch/x86/kernel/crash.c
>> +++ b/arch/x86/kernel/crash.c
>> @@ -266,6 +266,7 @@ static int memmap_exclude_ranges(struct kimage *image, struct crash_mem *cmem,
>>  				 unsigned long long mend)
>>  {
>>  	unsigned long start, end;
>> +	int r;
>            ~?
>
>r is only to contain the returned value? Then you can call it ret as
>many do in kernel code.

Applied to v6, thanks for the suggestion!

>
>>
>>  	cmem->ranges[0].start = mstart;
>>  	cmem->ranges[0].end = mend;
>> @@ -274,7 +275,19 @@ static int memmap_exclude_ranges(struct kimage *image, struct crash_mem *cmem,
>>  	/* Exclude elf header region */
>>  	start = image->elf_load_addr;
>>  	end = start + image->elf_headers_sz - 1;
>> -	return crash_exclude_mem_range(cmem, start, end);
>> +	r = crash_exclude_mem_range(cmem, start, end);
>> +
>> +	if (r)
>> +		return r;
>> +
>> +	/* Exclude dm crypt keys region */
>> +	if (image->dm_crypt_keys_addr) {
>> +		start = image->dm_crypt_keys_addr;
>> +		end = start + image->dm_crypt_keys_sz - 1;
>> +		return crash_exclude_mem_range(cmem, start, end);
>> +	}
>
>You need adjust the array length of cmem->ranges[], I believe you will
>cause the array overflow because the keys are randomly set and mostly
>will be in the middle of crashkernel region.

Yes, you are absolutely right. I've fixed in v6.


-- 
Best regards,
Coiby