[PATCH 5.14 691/849] mtd: core: dont remove debugfs directory if device is in use

Greg Kroah-Hartman
2021-11-16T01:17:17Z

From: Zev Weiss <zev@bewilderbeest.net>

[ Upstream commit c13de2386c78e890d4ae6f01a85eefd0b293fb08 ]

Previously, if del_mtd_device() failed with -EBUSY due to a non-zero
usecount, a subsequent call to attempt the deletion again would try to
remove a debugfs directory that had already been removed and panic.
With this change the second call can instead proceed safely.

Fixes: e8e3edb95ce6 ("mtd: create per-device and module-scope debugfs entries")
Signed-off-by: Zev Weiss <zev@bewilderbeest.net>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20211014203953.5424-1-zev@bewilderbeest.net
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/mtd/mtdcore.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
index c8fd7f758938b..1532291989471 100644
--- a/drivers/mtd/mtdcore.c
+++ b/drivers/mtd/mtdcore.c
@@ -724,8 +724,6 @@ int del_mtd_device(struct mtd_info *mtd)

mutex_lock(&mtd_table_mutex);

- debugfs_remove_recursive(mtd->dbg.dfs_dir);
-
if (idr_find(&mtd_idr, mtd->index) != mtd) {
ret = -ENODEV;
goto out_error;
@@ -741,6 +739,8 @@ int del_mtd_device(struct mtd_info *mtd)
mtd->index, mtd->name, mtd->usecount);
ret = -EBUSY;
} else {
+ debugfs_remove_recursive(mtd->dbg.dfs_dir);
+
/* Try to remove the NVMEM provider */
if (mtd->nvmem)
nvmem_unregister(mtd->nvmem);
--
2.33.0