Re: [PATCH v4 6/7] x86/crash: pass dm crypt keys to kdump kernel

Coiby Xu
2024-06-07T12:28:36Z

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