[Skiboot] [RFC PATCH] core/lock: Add debug options to store backtrace of where lock was taken

[Andrew Donnellan]

On 25/2/19 5:11 pm, Stewart Smith wrote:
>> +/* Enable printing of backtraces when locks not released */
>> +#define DEBUG_LOCKS_BACKTRACE  1
> 
> this is behind a #if for DEBUG=1, right?

it is not, but I can fix that...

> 
>> +
>>   /* Enable lock dependency checker */
>>   #define DEADLOCK_CHECKER	1
>>   
>> diff --git a/include/lock.h b/include/lock.h
>> index b18757394dbb..b7d47be83ba9 100644
>> --- a/include/lock.h
>> +++ b/include/lock.h
>> @@ -23,6 +23,10 @@
>>   #include <ccan/list/list.h>
>>   #include <ccan/str/str.h>
>>   
>> +#ifdef DEBUG_LOCKS_BACKTRACE
>> +#include <stack.h>
>> +#endif
>> +
>>   struct lock {
>>   	/* Lock value has bit 63 as lock bit and the PIR of the owner
>>   	 * in the top 32-bit
>> @@ -38,6 +42,14 @@ struct lock {
>>   	/* file/line of lock owner */
>>   	const char *owner;
>>   
>> +#ifdef DEBUG_LOCKS_BACKTRACE
>> +	struct bt_entry bt_buf[60];
>> +	unsigned int bt_ents;
>> +	unsigned long bt_token;
>> +	unsigned long bt_r1_caller;
>> +	unsigned long bt_pir;
>> +#endif
> 
> almost feels like it should be a struct.

And if we made it a struct, that would make it easier to clean up the 
API and make stuff like this easier in future... hmm...

> 
>> +
>>   	/* linkage in per-cpu list of owned locks */
>>   	struct list_node list;
>>   };
>> -- 
>> 2.11.0
>>
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> 

-- 
Andrew Donnellan              OzLabs, ADL Canberra
andrew.donnellan at au1.ibm.com  IBM Australia Limited