Re: KASAN: use-after-free Read in percpu_ref_switch_to_atomic_rcu

Dan Carpenter
2020-03-06T14:36:39Z

There a bunch of similar bugs. It's seems a common anti-pattern.

block/blk-cgroup.c:85 blkg_free() warn: freeing 'blkg' which has percpu_ref_exit()
block/blk-core.c:558 blk_alloc_queue_node() warn: freeing 'q' which has percpu_ref_exit()
drivers/md/md.c:5528 md_free() warn: freeing 'mddev' which has percpu_ref_exit()
drivers/target/target_core_transport.c:583 transport_free_session() warn: freeing 'se_sess' which has percpu_ref_exit()
fs/aio.c:592 free_ioctx() warn: freeing 'ctx' which has percpu_ref_exit()
fs/aio.c:806 ioctx_alloc() warn: freeing 'ctx' which has percpu_ref_exit()
fs/io_uring.c:6115 io_sqe_files_unregister() warn: freeing 'data' which has percpu_ref_exit()
fs/io_uring.c:6431 io_sqe_files_register() warn: freeing 'ctx->file_data' which has percpu_ref_exit()
fs/io_uring.c:7134 io_ring_ctx_free() warn: freeing 'ctx' which has percpu_ref_exit()
kernel/cgroup/cgroup.c:4948 css_free_rwork_fn() warn: freeing 'css' which has percpu_ref_exit()
mm/backing-dev.c:615 cgwb_create() warn: freeing 'wb' which has percpu_ref_exit()

regards,
dan carpenter