selftests/bpf: Tracing prog can still do lookup under busy lock

2022-10-26T06:11:47Z

This patch modifies the task_ls_recursion test to check that the first bpf_task_storage_get(&map_a, ...) in BPF_PROG(on_update) can still do the lockless lookup even it cannot acquire the percpu busy lock. If the lookup succeeds, it will increment the value by 1 and the value in the task storage map_a will become 200+1=201. After that, BPF_PROG(on_update) tries to delete from map_a and should get -EBUSY because it cannot acquire the percpu busy lock after finding the data. Signed-off-by: Martin KaFai Lau Link: https://lore.kernel.org/r/20221025184524.3526117-10-martin.lau@linux.dev Signed-off-by: Alexei Starovoitov

selftests/bpf: Test deadlock from recursive bpf_task_storage_[get|delete]

2021-02-26T19:51:48Z

Add a test with recursive bpf_task_storage_[get|delete] from fentry programs on bpf_local_storage_lookup and bpf_local_storage_update. Without proper deadlock prevent mechanism, this test would cause deadlock. Signed-off-by: Song Liu Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20210225234319.336131-5-songliubraving@fb.com

kernel/tools/testing/selftests/bpf/progs/task_ls_recursion.c, branch linux-6.2.y

selftests/bpf: Tracing prog can still do lookup under busy lock

selftests/bpf: Test deadlock from recursive bpf_task_storage_[get|delete]