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Commit bd206a06 authored by Javier González's avatar Javier González Committed by Greg Kroah-Hartman
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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: default avatarJavier González <javier@cnexlabs.com>
Signed-off-by: default avatarMatias Bjørling <mb@lightnvm.io>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 5764ffc8

drivers/lightnvm/pblk-core.c

+3 −2
Original line number Diff line number Diff line
@@ -1539,13 +1539,14 @@ 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);

drivers/lightnvm/pblk-sysfs.c

+7 −1
Original line number Diff line number Diff line
@@ -262,8 +262,14 @@ 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);



		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);