From: Hou Tao <houtao1@xxxxxxxxxx>
Hi,
The patchset aims to make the update of bpf_task_storage_busy being
preemption-safe. The problem is on same architectures (e.g. arm64),
__this_cpu_{inc|dec|inc_return} are neither preemption-safe nor
IRQ-safe, so the concurrent lookups or updates on the same task local
storage and the same CPU may make bpf_task_storage_busy be imbalanced,
and bpf_task_storage_trylock() on specific cpu will always fail.
Patch 1 fixes the problem by using preemption/IRQ-safe per-cpu helpers.
And patch 2 & patch 3 add a test case for the problem. Comments are
always welcome.
Regards,
Tao
Hou Tao (3):
bpf: Use this_cpu_{inc|dec|inc_return} for bpf_task_storage_busy
selftests/bpf: Move sys_pidfd_open() into test_progs.h
selftests/bpf: Test concurrent updates on bpf_task_storage_busy
kernel/bpf/bpf_local_storage.c | 4 +-
kernel/bpf/bpf_task_storage.c | 8 +-
.../bpf/prog_tests/task_local_storage.c | 91 +++++++++++++++++++
.../selftests/bpf/prog_tests/test_bprm_opts.c | 9 --
.../bpf/prog_tests/test_local_storage.c | 9 --
tools/testing/selftests/bpf/test_progs.h | 9 ++
6 files changed, 106 insertions(+), 24 deletions(-)
--
2.29.2
