Re: [PATCH] livepatch: fix race between enabled_store() and klp_unregister_patch()

Jiri Slaby
2015-12-01T08:50:29Z

On 12/01/2015, 02:11 AM, Josh Poimboeuf wrote:
> When I try to recreate something similar by putting a delay in
> enabled_store(), klp_free_patch() just sleeps on its call to
> kobject_put() until enabled_store() returns. The unregister stack looks
> like:
>
> [<ffffffff812e966b>] __kernfs_remove+0x1fb/0x380
> [<ffffffff812ea273>] kernfs_remove+0x23/0x40
> [<ffffffff812ec601>] sysfs_remove_dir+0x51/0x80
> [<ffffffff81407fb8>] kobject_del+0x18/0x50
> [<ffffffff8140804a>] kobject_release+0x5a/0x190
> [<ffffffff81407f27>] kobject_put+0x27/0x50

What about _put outside of klp_mutex in klp_unregister_patch (and maybe
the other _put's as well)? Plus Li Bin's patch.

thanks,
--
js
suse labs