[PATCH AUTOSEL 5.4 323/330] ubi: fastmap: Free unused fastmap anchor peb during detach

Sasha Levin
2020-09-18T02:53:21Z

From: Hou Tao <houtao1@huawei.com>

[ Upstream commit c16f39d14a7e0ec59881fbdb22ae494907534384 ]

When CONFIG_MTD_UBI_FASTMAP is enabled, fm_anchor will be assigned
a free PEB during ubi_wl_init() or ubi_update_fastmap(). However
if fastmap is not used or disabled on the MTD device, ubi_wl_entry
related with the PEB will not be freed during detach.

So Fix it by freeing the unused fastmap anchor during detach.

Fixes: f9c34bb52997 ("ubi: Fix producing anchor PEBs")
Reported-by: syzbot+f317896aae32eb281a58@syzkaller.appspotmail.com
Reviewed-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/mtd/ubi/fastmap-wl.c | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/ubi/fastmap-wl.c b/drivers/mtd/ubi/fastmap-wl.c
index 426820ab9afe1..b486250923c5a 100644
--- a/drivers/mtd/ubi/fastmap-wl.c
+++ b/drivers/mtd/ubi/fastmap-wl.c
@@ -39,6 +39,13 @@ static struct ubi_wl_entry *find_anchor_wl_entry(struct rb_root *root)
return victim;
}

+static inline void return_unused_peb(struct ubi_device *ubi,
+ struct ubi_wl_entry *e)
+{
+ wl_tree_add(e, &ubi->free);
+ ubi->free_count++;
+}
+
/**
* return_unused_pool_pebs - returns unused PEB to the free tree.
* @ubi: UBI device description object
@@ -52,8 +59,7 @@ static void return_unused_pool_pebs(struct ubi_device *ubi,

for (i = pool->used; i < pool->size; i++) {
e = ubi->lookuptbl[pool->pebs[i]];
- wl_tree_add(e, &ubi->free);
- ubi->free_count++;
+ return_unused_peb(ubi, e);
}
}

@@ -361,6 +367,11 @@ static void ubi_fastmap_close(struct ubi_device *ubi)
return_unused_pool_pebs(ubi, &ubi->fm_pool);
return_unused_pool_pebs(ubi, &ubi->fm_wl_pool);

+ if (ubi->fm_anchor) {
+ return_unused_peb(ubi, ubi->fm_anchor);
+ ubi->fm_anchor = NULL;
+ }
+
if (ubi->fm) {
for (i = 0; i < ubi->fm->used_blocks; i++)
kfree(ubi->fm->e[i]);
--
2.25.1