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authorJavier González <javier@javigon.com>2018-10-09 13:12:07 +0200
committerJens Axboe <axboe@kernel.dk>2018-10-09 08:25:08 -0600
commit44cdbdc657b23f75736eca3e88b781f009104363 (patch)
treedb6d14e7d352ee04ff6f7ec6ea20a34fdf990d8d
parent02a1520d56d11982ccc8eab56e4c562fd05d2c86 (diff)
lightnvm: pblk: fix race on sysfs line state
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 <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <mb@lightnvm.io> Signed-off-by: Jens Axboe <axboe@kernel.dk>
-rw-r--r--drivers/lightnvm/pblk-core.c5
-rw-r--r--drivers/lightnvm/pblk-sysfs.c8
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;
- l_mg->data_line = new;
spin_lock(&l_mg->free_lock);
+ cur = l_mg->data_line;
+ l_mg->data_line = new;
+
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);