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[199.255.44.250]) by smtp.gmail.com with ESMTPSA id p1-v6sm25342380pff.128.2018.10.09.04.15.15 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 09 Oct 2018 04:15:17 -0700 (PDT) From: =?UTF-8?q?Matias=20Bj=C3=B8rling?= To: axboe@fb.com Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, =?UTF-8?q?Javier=20Gonz=C3=A1lez?= , =?UTF-8?q?Javier=20Gonz=C3=A1lez?= , =?UTF-8?q?Matias=20Bj=C3=B8rling?= Subject: [GIT PULL 37/45] lightnvm: pblk: fix race on sysfs line state Date: Tue, 9 Oct 2018 13:12:07 +0200 Message-Id: <20181009111215.7653-38-mb@lightnvm.io> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20181009111215.7653-1-mb@lightnvm.io> References: <20181009111215.7653-1-mb@lightnvm.io> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Javier González pblk exposes a sysfs interface that represents its internal state. Part of this state is the map bitmap for the current open line, which should be protected by the line lock to avoid a race when freeing the line metadata. Currently, it is not. This patch makes sure that the line state is consistent and NULL bitmap pointers are not dereferenced. Signed-off-by: Javier González Signed-off-by: Matias Bjørling --- drivers/lightnvm/pblk-core.c | 5 +++-- drivers/lightnvm/pblk-sysfs.c | 8 +++++++- 2 files changed, 10 insertions(+), 3 deletions(-) diff --git a/drivers/lightnvm/pblk-core.c b/drivers/lightnvm/pblk-core.c index 4045a9b1ee74..6944aac43b01 100644 --- a/drivers/lightnvm/pblk-core.c +++ b/drivers/lightnvm/pblk-core.c @@ -1611,13 +1611,14 @@ struct pblk_line *pblk_line_replace_data(struct pblk *pblk) struct pblk_line *cur, *new = NULL; unsigned int left_seblks; - cur = l_mg->data_line; new = l_mg->data_next; if (!new) goto out; + + spin_lock(&l_mg->free_lock); + cur = l_mg->data_line; l_mg->data_line = new; - spin_lock(&l_mg->free_lock); pblk_line_setup_metadata(new, l_mg, &pblk->lm); spin_unlock(&l_mg->free_lock); diff --git a/drivers/lightnvm/pblk-sysfs.c b/drivers/lightnvm/pblk-sysfs.c index cba83ac43e62..2d2818155aa8 100644 --- a/drivers/lightnvm/pblk-sysfs.c +++ b/drivers/lightnvm/pblk-sysfs.c @@ -263,8 +263,14 @@ static ssize_t pblk_sysfs_lines(struct pblk *pblk, char *page) sec_in_line = l_mg->data_line->sec_in_line; meta_weight = bitmap_weight(&l_mg->meta_bitmap, PBLK_DATA_LINES); - map_weight = bitmap_weight(l_mg->data_line->map_bitmap, + + spin_lock(&l_mg->data_line->lock); + if (l_mg->data_line->map_bitmap) + map_weight = bitmap_weight(l_mg->data_line->map_bitmap, lm->sec_per_line); + else + map_weight = 0; + spin_unlock(&l_mg->data_line->lock); } spin_unlock(&l_mg->free_lock); -- 2.17.1