Re: [PATCH bpf-next v4 1/9] bpf: Allow LSM programs to use bpf spin locks

[Song Liu]

> On Nov 5, 2020, at 6:47 AM, KP Singh <kpsingh@xxxxxxxxxxxx> wrote:
> 
> From: KP Singh <kpsingh@xxxxxxxxxx>
> 
> 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@xxxxxxxxxxxx/T/#md601a053229287659071600d3483523f752cd2fb
> 
> Signed-off-by: KP Singh <kpsingh@xxxxxxxxxx>

Acked-by: Song Liu <songliubraving@xxxxxx>

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