From: Greg Kroah-Hartman Date: Tue, 16 May 2023 19:20:14 +0000 (+0200) Subject: driver core: class: properly reference count class_dev_iter() X-Git-Tag: v6.6.7~2816^2 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=ddaf098ea779b3c1302c7843f6ff01e89b1fd380;p=platform%2Fkernel%2Flinux-starfive.git driver core: class: properly reference count class_dev_iter() When class_dev_iter is initialized, the reference count for the subsys private structure is incremented, but never decremented, causing a memory leak over time. To resolve this, save off a pointer to the internal structure into the class_dev_iter structure and then when the iterator is finished, drop the reference count. Reported-and-tested-by: syzbot+e7afd76ad060fa0d2605@syzkaller.appspotmail.com Fixes: 7b884b7f24b4 ("driver core: class.c: convert to only use class_to_subsys") Reported-by: Mirsad Goran Todorovac Cc: Alan Stern Acked-by: Rafael J. Wysocki Tested-by: Mirsad Goran Todorovac Link: https://lore.kernel.org/r/2023051610-stove-condense-9a77@gregkh Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/base/class.c b/drivers/base/class.c index ac1808d..05d9df9 100644 --- a/drivers/base/class.c +++ b/drivers/base/class.c @@ -320,6 +320,7 @@ void class_dev_iter_init(struct class_dev_iter *iter, const struct class *class, start_knode = &start->p->knode_class; klist_iter_init_node(&sp->klist_devices, &iter->ki, start_knode); iter->type = type; + iter->sp = sp; } EXPORT_SYMBOL_GPL(class_dev_iter_init); @@ -361,6 +362,7 @@ EXPORT_SYMBOL_GPL(class_dev_iter_next); void class_dev_iter_exit(struct class_dev_iter *iter) { klist_iter_exit(&iter->ki); + subsys_put(iter->sp); } EXPORT_SYMBOL_GPL(class_dev_iter_exit); diff --git a/include/linux/device/class.h b/include/linux/device/class.h index 9deeaeb..abf3d3b 100644 --- a/include/linux/device/class.h +++ b/include/linux/device/class.h @@ -74,6 +74,7 @@ struct class { struct class_dev_iter { struct klist_iter ki; const struct device_type *type; + struct subsys_private *sp; }; int __must_check class_register(const struct class *class);