lightnvm: pblk: fix race on sysfs line state
[ Upstream commit 44cdbdc657b23f75736eca3e88b781f009104363 ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/lightnvm/pblk-core.c b/drivers/lightnvm/pblk-core.c
index 00984b4..2940cdc 100644
--- a/drivers/lightnvm/pblk-core.c
+++ b/drivers/lightnvm/pblk-core.c
@@ -1539,13 +1539,14 @@
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);