[Crash-utility] Problem with "timer" command on RHEL7.6

[Kazuhito Hagio]

On 8/1/2019 1:22 PM, Dave Anderson wrote:
> 
> 
> ----- Original Message -----
>> Hi Dave,
>>
>> I noticed that the "timer" command prints somewhat wrongly for RHEL7.6 or
>> later kernels (not including RHEL8 / upstream) and found that it is because
>> struct tvec and tvec_root have an array of list_head, instead of hlist_head
>> in upstream kernels.
>>
>> So the following patch looks good only for RHEL7, but I don't know how we
>> should determine the list type in order to switch the size, etc in this case.
>> What do you think?
> 
> Try using the MEMBER_TYPE_NAME() macro.  For example, adding this to cmd_test():

Nice. I'll try to rewrite the patch with it.

Thanks!
Kazu

> 
> --- a/test.c	2011-09-01 14:06:56.000000000 -0400
> +++ b/test.c	2019-08-01 13:16:13.783615151 -0400
> @@ -58,6 +58,7 @@ cmd_test(void)
>                  ;
>                  optind++;
>          }
> +fprintf(fp, "%s\n", MEMBER_TYPE_NAME("tvec_root", "vec"));
>  }
>  
> shows this on a RHEL7 kernel:
> 
>   crash> struct tvec_root
>   struct tvec_root {
>       struct list_head vec[256];
>   }
>   SIZE: 409
>   crash> test
>   list_head
>   crash> s
> 
> Dave
> 
>>
>> Thanks,
>> Kazu
>>
>> ---
>> diff --git a/kernel.c b/kernel.c
>> index a79e5a3010ea..419cca3ac7ae 100644
>> --- a/kernel.c
>> +++ b/kernel.c
>> @@ -8376,7 +8376,7 @@ dump_timer_data_tvec_bases_v3(const ulong *cpus)
>>  	char buf4[BUFSIZE];
>>  
>>  	vec_root_size = vec_size = 0;
>> -	head_size = SIZE(hlist_head);
>> +	head_size = SIZE(list_head);
>>  
>>  	if ((i = get_array_length("tvec_root.vec", NULL, head_size)))
>>  		vec_root_size = i;
>> @@ -8804,19 +8804,19 @@ do_timer_list_v3(ulong vec_kvaddr,
>>  			tdx++;
>>  	}
>>  
>> -	readmem(vec_kvaddr, KVADDR, vec, SIZE(hlist_head) * size,
>> +	readmem(vec_kvaddr, KVADDR, vec, SIZE(list_head) * size,
>>  		"timer_list vec array", FAULT_ON_ERROR);
>>  
>>  	ld = &list_data;
>>  	timer_list_buf = GETBUF(SIZE(timer_list));
>>  
>> -	for (i = count = 0; i < size; i++, vec_kvaddr += SIZE(hlist_head)) {
>> +	for (i = count = 0; i < size; i++, vec_kvaddr += SIZE(list_head)) {
>>  
>> -		if (vec[i] == 0)
>> +		if (vec[i*2] == vec_kvaddr)
>>  			continue;
>>  
>>  		BZERO(ld, sizeof(struct list_data));
>> -		ld->start = vec[i];
>> +		ld->start = vec[i*2];
>>  		ld->list_head_offset = OFFSET(timer_list_entry);
>>  		ld->end = vec_kvaddr;
>>  		ld->flags = RETURN_ON_LIST_ERROR;
>>
> 
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