From 0e5596c54aa2fbfd22842096d3ebb6753b2a220a Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Sun, 24 May 2020 17:30:41 +0200 Subject: kobject: send KOBJ_REMOVE uevent when the object is removed from sysfs It is possible for a KOBJ_REMOVE uevent to be sent to userspace way after the files are actually gone from sysfs, due to how reference counting for kobjects work. This should not be a problem, but it would be good to properly send the information when things are going away, not at some later point in time in the future. Before this move, if a kobject's parent was torn down before the child, when the call to kobject_uevent() happened, the parent walk to try to reconstruct the full path of the kobject could be a total mess and cause crashes. It's not good to try to tear down a kobject tree from top down, but let's at least try to not to crash if a user does so. Reviewed-by: Rafael J. Wysocki Link: https://lore.kernel.org/r/20200524153041.2361-2-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman --- lib/kobject.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) (limited to 'lib/kobject.c') diff --git a/lib/kobject.c b/lib/kobject.c index 83198cb37d8d..2509e22ad74a 100644 --- a/lib/kobject.c +++ b/lib/kobject.c @@ -620,6 +620,13 @@ void kobject_del(struct kobject *kobj) if (ktype) sysfs_remove_groups(kobj, ktype->default_groups); + /* send "remove" if the caller did not do it but sent "add" */ + if (kobj->state_add_uevent_sent && !kobj->state_remove_uevent_sent) { + pr_debug("kobject: '%s' (%p): auto cleanup 'remove' event\n", + kobject_name(kobj), kobj); + kobject_uevent(kobj, KOBJ_REMOVE); + } + sysfs_remove_dir(kobj); sysfs_put(sd); @@ -673,13 +680,6 @@ static void kobject_cleanup(struct kobject *kobj) pr_debug("kobject: '%s' (%p): does not have a release() function, it is broken and must be fixed. See Documentation/kobject.txt.\n", kobject_name(kobj), kobj); - /* send "remove" if the caller did not do it but sent "add" */ - if (kobj->state_add_uevent_sent && !kobj->state_remove_uevent_sent) { - pr_debug("kobject: '%s' (%p): auto cleanup 'remove' event\n", - kobject_name(kobj), kobj); - kobject_uevent(kobj, KOBJ_REMOVE); - } - /* remove from sysfs if the caller did not do it */ if (kobj->state_in_sysfs) { pr_debug("kobject: '%s' (%p): auto cleanup kobject_del\n", -- cgit v1.2.3-70-g09d2