In the Linux kernel, the following vulnerability has been resolved:
RDMA/rtrs: Fix use-after-free in path file creation cleanup
In the error path of rtrs_srv_create_path_files(), the sysfs root folders
may already have been created and srv_path->kobj may already have been
initialized. If a later step fails, the cleanup currently calls
kobject_put(&srv_path->kobj) before
rtrs_srv_destroy_once_sysfs_root_folders(srv_path).
kobject_put() may drop the last reference to srv_path->kobj and invoke the
release callback, rtrs_srv_release(), which frees srv_path. The following
call to rtrs_srv_destroy_once_sysfs_root_folders(srv_path) then
dereferences srv_path internally to access srv_path->srv, resulting in a
use-after-free.
This failure path is reached before rtrs_srv_create_path_files() returns
success, so the successful-path lifetime handling is not involved.
Fix this by destroying the sysfs root folders before calling
kobject_put(&srv_path->kobj), so srv_path is still valid while the helper
accesses it.
This issue was found by a static analysis tool I am developing.