4.18-stable review patch. If anyone has any objections, please let me know.
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From: Javier González javier@cnexlabs.com
[ 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 --- drivers/lightnvm/pblk-core.c | 5 +++-- drivers/lightnvm/pblk-sysfs.c | 8 +++++++- 2 files changed, 10 insertions(+), 3 deletions(-)
--- a/drivers/lightnvm/pblk-core.c +++ b/drivers/lightnvm/pblk-core.c @@ -1538,13 +1538,14 @@ struct pblk_line *pblk_line_replace_data 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);
--- a/drivers/lightnvm/pblk-sysfs.c +++ b/drivers/lightnvm/pblk-sysfs.c @@ -262,8 +262,14 @@ static ssize_t pblk_sysfs_lines(struct p 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);