[PATCH v4 06/10] staging: next: configfs: fix release link
Christian Gromm
christian.gromm at microchip.com
Thu Jan 23 15:38:22 UTC 2020
The functions link_destroy and link_release are both deleting list items.
link_release, however, does not check whether a certain link has already
been deleted from the list by function link_destroy. By fixing this
this patch prevents a kernel crash when removing the configuration
directory of a link that already has been destroyed.
Signed-off-by: Christian Gromm <christian.gromm at microchip.com>
---
v4:
This patch has been added to the series
drivers/staging/most/configfs.c | 26 +++++++++++++++++++-------
1 file changed, 19 insertions(+), 7 deletions(-)
diff --git a/drivers/staging/most/configfs.c b/drivers/staging/most/configfs.c
index 9818f6c..982d1a1 100644
--- a/drivers/staging/most/configfs.c
+++ b/drivers/staging/most/configfs.c
@@ -127,6 +127,8 @@ static ssize_t mdev_link_create_link_store(struct config_item *item,
return ret;
list_add_tail(&mdev_link->list, &mdev_link_list);
mdev_link->create_link = tmp;
+ mdev_link->destroy_link = false;
+
return count;
}
@@ -142,13 +144,16 @@ static ssize_t mdev_link_destroy_link_store(struct config_item *item,
return ret;
if (!tmp)
return count;
- mdev_link->destroy_link = tmp;
+
ret = most_remove_link(mdev_link->device, mdev_link->channel,
mdev_link->comp);
if (ret)
return ret;
if (!list_empty(&mdev_link_list))
list_del(&mdev_link->list);
+
+ mdev_link->destroy_link = tmp;
+
return count;
}
@@ -377,13 +382,20 @@ static void mdev_link_release(struct config_item *item)
struct mdev_link *mdev_link = to_mdev_link(item);
int ret;
- if (!list_empty(&mdev_link_list)) {
- ret = most_remove_link(mdev_link->device, mdev_link->channel,
- mdev_link->comp);
- if (ret && (ret != -ENODEV))
- pr_err("Removing link failed.\n");
- list_del(&mdev_link->list);
+ if (mdev_link->destroy_link)
+ goto free_item;
+
+ ret = most_remove_link(mdev_link->device, mdev_link->channel,
+ mdev_link->comp);
+ if (ret) {
+ pr_err("Removing link failed.\n");
+ goto free_item;
}
+
+ if (!list_empty(&mdev_link_list))
+ list_del(&mdev_link->list);
+
+free_item:
kfree(to_mdev_link(item));
}
--
2.7.4
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