Merge branch 'bpf: refine retval for bpf_get_task_stack helper'
authorAlexei Starovoitov <ast@kernel.org>
Tue, 20 Apr 2021 01:23:34 +0000 (18:23 -0700)
committerAlexei Starovoitov <ast@kernel.org>
Tue, 20 Apr 2021 01:23:34 +0000 (18:23 -0700)
commit69443c47305e541f5bf8b5a26f442c0c7f34cafe
tree0a40b8c3beeb6f735fc54e932bdd5a85ad8ec3d8
parent137733d08f4ab14a354dacaa9a8fc35217747605
parentc77cec5c207b68a3cbc2af2f81070ec428f41145
Merge branch 'bpf: refine retval for bpf_get_task_stack helper'

Dave Marchevsky says:

====================

Similarly to the bpf_get_stack helper, bpf_get_task_stack's return value
can be more tightly bound by the verifier - it's the number of bytes
written to a user-supplied buffer, or a negative error value. Currently
the verifier believes bpf_task_get_stack's retval bounds to be unknown,
requiring extraneous bounds checking to remedy.

Adding it to do_refine_retval_range fixes the issue, as evidenced by
new selftests which fail to load if retval bounds are not refined.

v2: Addressed comment nit in patch 3
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>