Re: [PATCH v3] time/timgr: Fix wrong reference when level 0 group allocation failed

[Anna-Maria Behnsen <anna-maria@linutronix.de>]

Frederic Weisbecker <frederic@kernel.org> writes:

> Le Mon, May 06, 2024 at 05:10:59AM +0100, Levi Yun a écrit :
>> When tmigr_setup_groups() failed level 0 group allocation,
>> wrong reference happens on local stack array while intializing timer hierarchy.
>> 
>> To prevent this, Check loop condition first before initializing timer hierarchy.
>> 
>> Fixes: 7ee988770326 ("timers: Implement the hierarchical pull model")
>> Signed-off-by: Levi Yun <ppbuk5246@gmail.com>
>> ---
>> v3:
>>     - Fix typo.
>> 
>> v2:
>> 	- Modify commit message.
>> 
>>  kernel/time/timer_migration.c | 4 ++--
>>  1 file changed, 2 insertions(+), 2 deletions(-)
>> 
>> diff --git a/kernel/time/timer_migration.c b/kernel/time/timer_migration.c
>> index ccba875d2234..84413114db5c 100644
>> --- a/kernel/time/timer_migration.c
>> +++ b/kernel/time/timer_migration.c
>> @@ -1596,7 +1596,7 @@ static int tmigr_setup_groups(unsigned int cpu, unsigned int node)
>> 
>>  	} while (i < tmigr_hierarchy_levels);
>> 
>> -	do {
>> +	while (i > 0) {
>>  		group = stack[--i];
>> 
>>  		if (err < 0) {
>> @@ -1645,7 +1645,7 @@ static int tmigr_setup_groups(unsigned int cpu, unsigned int node)
>>  				tmigr_connect_child_parent(child, group);
>>  			}
>>  		}
>> -	} while (i > 0);
>> +	}
>
> Looks good to me. But let's wait for Anna-Maria's second look. The group setup
> is not my favourite area...
>

Thanks for the fix!

Reviewed-by: Anna-Maria Behnsen <anna-maria@linutronix.de>