Re: [PATCH] kmemleak: record accurate early log buffer count and report when exceeded

Wang Kai
2015-04-15T23:23:33Z

Thanks a lot for the correction.

On 2015/4/15 23:13, Catalin Marinas wrote:
> (I see you corrected the LKML address; I replied to your early patch)
>
> On Wed, Apr 15, 2015 at 12:49:23PM +0100, Wang Kai wrote:
>> In log_early function, crt_early_log should also count once when
>> 'crt_early_log >= ARRAY_SIZE(early_log)'. Otherwise the reported
>> count from kmemleak_init is one less than 'actual number'.
>>
>> Then, in kmemleak_init, if early_log buffer size equal actual
>> number, kmemleak will init sucessful, so change warning condition
>> to 'crt_early_log > ARRAY_SIZE(early_log)'.
>>
>> Signed-off-by: Wang Kai <morgan.wang@huawei.com>
>> ---
>> mm/kmemleak.c | 5 ++++-
>> 1 file changed, 4 insertions(+), 1 deletion(-)
>>
>> diff --git a/mm/kmemleak.c b/mm/kmemleak.c
>> index 5405aff..49956cf 100644
>> --- a/mm/kmemleak.c
>> +++ b/mm/kmemleak.c
>> @@ -814,6 +814,8 @@ static void __init log_early(int op_type, const void *ptr, size_t size,
>> }
>>
>> if (crt_early_log >= ARRAY_SIZE(early_log)) {
>> + /* kmemleak will stop recording, just count the requests */
>
> You could say "just count the last request" since kmemleak_disable()
> would set kmemleak_error to 1 and you never get to this block again.
>
>> + crt_early_log++;
>> kmemleak_disable();
>> return;
>> }
>> @@ -1829,7 +1831,8 @@ void __init kmemleak_init(void)
>> object_cache = KMEM_CACHE(kmemleak_object, SLAB_NOLEAKTRACE);
>> scan_area_cache = KMEM_CACHE(kmemleak_scan_area, SLAB_NOLEAKTRACE);
>>
>> - if (crt_early_log >= ARRAY_SIZE(early_log))
>> + /* Don't warning when crt_early_log == ARRAY_SIZE(early_log) */
>
> s/warning/warn/
>
> But I don't think this comment is needed, just add it to the commit log.
>
>> + if (crt_early_log > ARRAY_SIZE(early_log))
>> pr_warning("Early log buffer exceeded (%d), please increase "
>> "DEBUG_KMEMLEAK_EARLY_LOG_SIZE\n", crt_early_log);
>
> Otherwise, my ack still stands:
>
> Acked-by: Catalin Marinas <catalin.marinas@arm.com>
>
> .
>