From: Hou Tao <houtao1@xxxxxxxxxx>
Hi,
The patchset aims to fix the problem that bpf_mem_alloc() may return
NULL unexpectedly when multiple bpf_mem_alloc() are invoked concurrently
under process context and there is still free memory available. The
problem was found when doing stress test for qp-trie but the same
problem also exists for bpf_obj_new() as demonstrated in patch #3.
Patch #1 fixes the race between unit_alloc() and unit_alloc(). Patch
#2 fixes the race between unit_alloc() and unit_free(). And patch #3
adds a selftest for the problem. Please see individual patches for more
details. And comments are always welcome.
Hou Tao (3):
bpf: Enable preemption after irq_work_raise() in unit_alloc()
bpf: Enable preemption after irq_work_raise() in unit_free{_rcu}()
selftests/bpf: Test preemption between bpf_obj_new() and
bpf_obj_drop()
kernel/bpf/memalloc.c | 12 ++
.../bpf/prog_tests/preempted_bpf_ma_op.c | 89 +++++++++++++++
.../selftests/bpf/progs/preempted_bpf_ma_op.c | 106 ++++++++++++++++++
3 files changed, 207 insertions(+)
create mode 100644 tools/testing/selftests/bpf/prog_tests/preempted_bpf_ma_op.c
create mode 100644 tools/testing/selftests/bpf/progs/preempted_bpf_ma_op.c
--
2.29.2
