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authorKP Singh <kpsingh@google.com>2020-11-06 10:37:39 +0000
committerAlexei Starovoitov <ast@kernel.org>2020-11-06 08:08:37 -0800
commit9e7a4d9831e836eb03dedab89902277ee94eb7a6 (patch)
tree03732b15f5f401f21a500303b7441b11d927dfd0 /kernel/bpf/bpf_lsm.c
parentc6bde958a62b8ca5ee8d2c1fe429aec4ad54efad (diff)
bpf: Allow LSM programs to use bpf spin locks
Usage of spin locks was not allowed for tracing programs due to insufficient preemption checks. The verifier does not currently prevent LSM programs from using spin locks, but the helpers are not exposed via bpf_lsm_func_proto. Based on the discussion in [1], non-sleepable LSM programs should be able to use bpf_spin_{lock, unlock}. Sleepable LSM programs can be preempted which means that allowng spin locks will need more work (disabling preemption and the verifier ensuring that no sleepable helpers are called when a spin lock is held). [1]: https://lore.kernel.org/bpf/20201103153132.2717326-1-kpsingh@chromium.org/T/#md601a053229287659071600d3483523f752cd2fb Signed-off-by: KP Singh <kpsingh@google.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Song Liu <songliubraving@fb.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20201106103747.2780972-2-kpsingh@chromium.org
Diffstat (limited to 'kernel/bpf/bpf_lsm.c')
-rw-r--r--kernel/bpf/bpf_lsm.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/kernel/bpf/bpf_lsm.c b/kernel/bpf/bpf_lsm.c
index 78ea8a7bd27f..cd8a617f2109 100644
--- a/kernel/bpf/bpf_lsm.c
+++ b/kernel/bpf/bpf_lsm.c
@@ -59,6 +59,10 @@ bpf_lsm_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
return &bpf_sk_storage_get_proto;
case BPF_FUNC_sk_storage_delete:
return &bpf_sk_storage_delete_proto;
+ case BPF_FUNC_spin_lock:
+ return &bpf_spin_lock_proto;
+ case BPF_FUNC_spin_unlock:
+ return &bpf_spin_unlock_proto;
default:
return tracing_prog_func_proto(func_id, prog);
}