This is a note to let you know that I've just added the patch titled
driver core: Don't ignore class_dir_create_and_add() failure.
to my driver-core git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core.git
in the driver-core-testing branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will be merged to the driver-core-next branch sometime soon,
after it passes testing, and the merge window is open.
If you have any questions about this process, please let me know.
>From 84d0c27d6233a9ba0578b20f5a09701eb66cee42 Mon Sep 17 00:00:00 2001
From: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Date: Mon, 7 May 2018 19:10:31 +0900
Subject: driver core: Don't ignore class_dir_create_and_add() failure.
syzbot is hitting WARN() at kernfs_add_one() [1].
This is because kernfs_create_link() is confused by previous device_add()
call which continued without setting dev->kobj.parent field when
get_device_parent() failed by memory allocation fault injection.
Fix this by propagating the error from class_dir_create_and_add() to
the calllers of get_device_parent().
[1] https://syzkaller.appspot.com/bug?id=fae0fb607989ea744526d1c082a5b8de6529116f
Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Reported-by: syzbot <syzbot+df47f81c226b31d89fb1@xxxxxxxxxxxxxxxxxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: stable <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/base/core.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
diff --git a/drivers/base/core.c b/drivers/base/core.c
index b610816eb887..d680fd030316 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -1467,7 +1467,7 @@ class_dir_create_and_add(struct class *class, struct kobject *parent_kobj)
dir = kzalloc(sizeof(*dir), GFP_KERNEL);
if (!dir)
- return NULL;
+ return ERR_PTR(-ENOMEM);
dir->class = class;
kobject_init(&dir->kobj, &class_dir_ktype);
@@ -1477,7 +1477,7 @@ class_dir_create_and_add(struct class *class, struct kobject *parent_kobj)
retval = kobject_add(&dir->kobj, parent_kobj, "%s", class->name);
if (retval < 0) {
kobject_put(&dir->kobj);
- return NULL;
+ return ERR_PTR(retval);
}
return &dir->kobj;
}
@@ -1784,6 +1784,10 @@ int device_add(struct device *dev)
parent = get_device(dev->parent);
kobj = get_device_parent(dev, parent);
+ if (IS_ERR(kobj)) {
+ error = PTR_ERR(kobj);
+ goto parent_error;
+ }
if (kobj)
dev->kobj.parent = kobj;
@@ -1882,6 +1886,7 @@ int device_add(struct device *dev)
kobject_del(&dev->kobj);
Error:
cleanup_glue_dir(dev, glue_dir);
+parent_error:
put_device(parent);
name_error:
kfree(dev->p);
@@ -2701,6 +2706,11 @@ int device_move(struct device *dev, struct device *new_parent,
device_pm_lock();
new_parent = get_device(new_parent);
new_parent_kobj = get_device_parent(dev, new_parent);
+ if (IS_ERR(new_parent_kobj)) {
+ error = PTR_ERR(new_parent_kobj);
+ put_device(new_parent);
+ goto out;
+ }
pr_debug("device: '%s': %s: moving to '%s'\n", dev_name(dev),
__func__, new_parent ? dev_name(new_parent) : "<NULL>");
--
2.17.0
