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[95.166.82.66]) by smtp.googlemail.com with ESMTPSA id f25-v6sm3943351ljc.97.2018.09.04.03.11.52 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 04 Sep 2018 03:11:52 -0700 (PDT) Subject: Re: [PATCH] lightnvm: pblk: Fix two sleep-in-atomic-context bugs in pblk_line_submit_smeta_io() To: baijiaju1990@gmail.com Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, javier@cnexlabs.com, hans.holmberg@cnexlabs.com References: <20180901115318.30416-1-baijiaju1990@gmail.com> From: =?UTF-8?Q?Matias_Bj=c3=b8rling?= Message-ID: Date: Tue, 4 Sep 2018 12:11:51 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.5.0 MIME-Version: 1.0 In-Reply-To: <20180901115318.30416-1-baijiaju1990@gmail.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/01/2018 01:53 PM, Jia-Ju Bai wrote: > The driver may sleep with holding a spinlock. > > The function call paths (from bottom to top) in Linux-4.16 are: > > [FUNC] nvm_dev_dma_alloc(GFP_KERNEL) > drivers/lightnvm/pblk-core.c, 754: > nvm_dev_dma_alloc in pblk_line_submit_smeta_io > drivers/lightnvm/pblk-core.c, 1048: > pblk_line_submit_smeta_io in pblk_line_init_bb > drivers/lightnvm/pblk-core.c, 1434: > pblk_line_init_bb in pblk_line_replace_data > drivers/lightnvm/pblk-recovery.c, 980: > pblk_line_replace_data in pblk_recov_l2p > drivers/lightnvm/pblk-recovery.c, 976: > spin_lock in pblk_recov_l2p > > [FUNC] bio_map_kern(GFP_KERNEL) > drivers/lightnvm/pblk-core.c, 762: > bio_map_kern in pblk_line_submit_smeta_io > drivers/lightnvm/pblk-core.c, 1048: > pblk_line_submit_smeta_io in pblk_line_init_bb > drivers/lightnvm/pblk-core.c, 1434: > pblk_line_init_bb in pblk_line_replace_data > drivers/lightnvm/pblk-recovery.c, 980: > pblk_line_replace_data in pblk_recov_l2p > drivers/lightnvm/pblk-recovery.c, 976: > spin_lock in pblk_recov_l2p > > To fix these bugs, GFP_KERNEL is replaced with GFP_ATOMIC. > > These bugs are found by my static analysis tool DSAC. > > Signed-off-by: Jia-Ju Bai > --- > drivers/lightnvm/pblk-core.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/lightnvm/pblk-core.c b/drivers/lightnvm/pblk-core.c > index ed9cc977c8b3..5d915c93b6cf 100644 > --- a/drivers/lightnvm/pblk-core.c > +++ b/drivers/lightnvm/pblk-core.c > @@ -802,7 +802,7 @@ static int pblk_line_submit_smeta_io(struct pblk *pblk, struct pblk_line *line, > > memset(&rqd, 0, sizeof(struct nvm_rq)); > > - rqd.meta_list = nvm_dev_dma_alloc(dev->parent, GFP_KERNEL, > + rqd.meta_list = nvm_dev_dma_alloc(dev->parent, GFP_ATOMIC, > &rqd.dma_meta_list); > if (!rqd.meta_list) > return -ENOMEM; > @@ -810,7 +810,7 @@ static int pblk_line_submit_smeta_io(struct pblk *pblk, struct pblk_line *line, > rqd.ppa_list = rqd.meta_list + pblk_dma_meta_size; > rqd.dma_ppa_list = rqd.dma_meta_list + pblk_dma_meta_size; > > - bio = bio_map_kern(dev->q, line->smeta, lm->smeta_len, GFP_KERNEL); > + bio = bio_map_kern(dev->q, line->smeta, lm->smeta_len, GFP_ATOMIC); > if (IS_ERR(bio)) { > ret = PTR_ERR(bio); > goto free_ppa_list; > Javier, What do you think? I'm OK with applying this, but one could also move the allocs outside the spinlocks? -Matias