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Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.10.1 Subject: Re: [syzbot] [damon?] divide error in damon_set_attrs Content-Language: en-US To: SeongJae Park CC: syzbot , , , , , References: <20230527014635.7380-1-sj@kernel.org> From: Kefeng Wang In-Reply-To: <20230527014635.7380-1-sj@kernel.org> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.177.243] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To dggpemm500001.china.huawei.com (7.185.36.107) X-CFilter-Loop: Reflected X-Rspamd-Queue-Id: 2FE9540006 X-Rspam-User: X-Rspamd-Server: rspam05 X-Stat-Signature: s9uwphrcotdjad7zxkhtmznf5qwt96pe X-HE-Tag: 1685152962-344775 X-HE-Meta: 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 VNoNieDm /jS6BLZszW3zEH54P5l9fFaY2udZyBh/u8tLk5kJV1B7BJN4bPDWherq5re6S2v1egMSu7XRe/u64KcGhbHfFBSy025I/qUcsqTkYqdByWInBhvcC55QWUISlf9w6t1WXAjA0Rzq9LxQ71THo4fILn4HrWMQWucGcQ+CoAPWl0ifNIMjm6C/iQH54tqhsCbJf8r2BGVtIQr/3NO03L4o5VoiLjSfSBKCmcrqQcP0DadZ3+MnlglbD8MyuUjrO1O6b7qugNbUhFE74fxhXagEjItYy5K6QIneeKnYuSmZm1Et8UT1h4uWf9b6RBE4Vu90+jFiLe/irfrbQKNrYawXguX+Cow== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000020, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 2023/5/27 9:46, SeongJae Park wrote: > Hi Kefeng, > > On Sat, 27 May 2023 09:15:01 +0800 Kefeng Wang wrote: > > [...] >>> >>> Nice and effective fix! Nevertheless, I think aggregation interval smaller >>> than sample interval is just a wrong input. How about adding the check in >>> damon_set_attrs()'s already existing attributes validation, like below? >> >> Yes, move the check into damon_set_attrs() is better > > Thank you for this kind comment! > >> , and it seems that >> we could move all the check into it, and drop the old_attrs check in >> damon_update_monitoring_results(), what's you option? >> >> >> diff --git a/mm/damon/core.c b/mm/damon/core.c >> index d9ef62047bf5..1647f7f1f708 100644 >> --- a/mm/damon/core.c >> +++ b/mm/damon/core.c >> @@ -523,12 +523,6 @@ static void damon_update_monitoring_results(struct >> damon_ctx *ctx, >> struct damon_target *t; >> struct damon_region *r; >> >> - /* if any interval is zero, simply forgive conversion */ >> - if (!old_attrs->sample_interval || !old_attrs->aggr_interval || >> - !new_attrs->sample_interval || >> - !new_attrs->aggr_interval) >> - return; >> - >> damon_for_each_target(t, ctx) >> damon_for_each_region(r, t) >> damon_update_monitoring_result( >> @@ -551,6 +545,10 @@ int damon_set_attrs(struct damon_ctx *ctx, struct >> damon_attrs *attrs) >> return -EINVAL; >> if (attrs->min_nr_regions > attrs->max_nr_regions) >> return -EINVAL; >> + if (attrs->sample_interval > attrs->aggr_interval) >> + return -EINVAL; >> + if (!attrs->sample_interval || !attrs->aggr_interval) >> + return -EINVAL; > > In my humble opinion, the validation for monitoring results and for general > monitoring could be different. For example, zero aggreation/sampling intervals > might make sense for fixed granularity working set size monitoring. Hence, I'd > prefer keeping those checks in the damon_update_monitoring_results(). ok, will keep that, I check the damon_set_attrs() called by lru_sort/reclaim monitor and sysfs/dbgfs, the above changes should be ok, maybe missing something, the working set size monitoring is not public for now? > > > Thanks, > SJ > > [...]