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;
 
 	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);
+	}
+
+	return r;
 }
 
 /* Prepare memory map for crash dump kernel */
diff --git a/arch/x86/kernel/kexec-bzimage64.c b/arch/x86/kernel/kexec-bzimage64.c
index 68530fad05f7..9c94428927bd 100644
--- a/arch/x86/kernel/kexec-bzimage64.c
+++ b/arch/x86/kernel/kexec-bzimage64.c
@@ -76,6 +76,10 @@ static int setup_cmdline(struct kimage *image, struct boot_params *params,
 	if (image->type == KEXEC_TYPE_CRASH) {
 		len = sprintf(cmdline_ptr,
 			"elfcorehdr=0x%lx ", image->elf_load_addr);
+
+		if (image->dm_crypt_keys_addr != 0)
+			len += sprintf(cmdline_ptr + len,
+					"dmcryptkeys=0x%lx ", image->dm_crypt_keys_addr);
 	}
 	memcpy(cmdline_ptr + len, cmdline, cmdline_len);
 	cmdline_len += len;
@@ -441,6 +445,9 @@ static void *bzImage64_load(struct kimage *image, char *kernel,
 		ret = crash_load_segments(image);
 		if (ret)
 			return ERR_PTR(ret);
+		ret = crash_load_dm_crypt_keys(image);
+		if (ret)
+			pr_debug("Either no dm crypt key or error to retrieve the dm crypt key\n");
 	}
 #endif
 
-- 
2.45.0

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.

>  
>  	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.

> +
> +	return r;
>  }
>  
>  /* Prepare memory map for crash dump kernel */

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