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From: SeongJae Park <sj@kernel.org>
To: Dan Carpenter <dan.carpenter@linaro.org>
Cc: oe-kbuild@lists.linux.dev,
	SeongJae Park <sj@kernel.org>,
	lkp@intel.com,
	oe-kbuild-all@lists.linux.dev,
	damon@lists.linux.dev
Subject: Re: [sj:damon/next 32/42] mm/damon/core.c:1150 damos_set_effective_quota() error: uninitialized symbol 'esz'.
Date: Tue, 21 Nov 2023 17:36:02 +0000
Message-Id: <20231121173602.62313-1-sj@kernel.org>
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Hi Dan,

On Tue, 21 Nov 2023 02:37:12 -0500 Dan Carpenter <dan.carpenter@linaro.org> wrote:

> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/sj/linux.git damon/next
> head:   54ffd8ae08121d8cbce1874fe46970cce643a2c7
> commit: 28cef0e565adbb4175f12ffffce9d0680979de60 [32/42] mm/damon/core: implement goal-oriented feedback-driven quota auto-tuning
> config: x86_64-randconfig-161-20231121 (https://download.01.org/0day-ci/archive/20231121/202311210420.URG3QSAS-lkp@intel.com/config)
> compiler: gcc-11 (Debian 11.3.0-12) 11.3.0
> reproduce: (https://download.01.org/0day-ci/archive/20231121/202311210420.URG3QSAS-lkp@intel.com/reproduce)
> 
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@intel.com>
> | Reported-by: Dan Carpenter <error27@gmail.com>
> | Closes: https://lore.kernel.org/r/202311210420.URG3QSAS-lkp@intel.com/
> 
> smatch warnings:
> mm/damon/core.c:1150 damos_set_effective_quota() error: uninitialized symbol 'esz'.

Thank you for this nice report!

However, damos_set_effective_quota() is called from damos_adjust_quota(), which
ensures at least one among quota->{ms,sz,get_score} is nonzero.  And
damos_set_effective_quota() ensures quota->{ms,get_score} is non-zero at the
beginning of the function.  Then the function sets esz anyway, for non-zero
quota->ms and quota->get_score.  Hence the uninitialized variable usage cannot
happen, if I understand correctly.  Please let me know if I'm missing
something.


Thanks,
SJ