InScopedProtocol::drop, we currently panic ifclose_protocol returns something other thanStatus::SUCCESS.

I've observed that on some firmware, this can cause a problem if the same protocol is opened twice in non-exclusive mode viaOpenProtocolAttributes::GetProtocol. In general you shouldn't open the same protocol twice, but with a read-only protocol likeDevicePath it should be fine to do so. However, this can lead to the following situation:

fndo_something(h1:Handle,h2:Handle2){{let dp1 = boot::open_protocol::<DevicePath>(OpenProtocolParams{handle: h1,agent: boot::image_handle(),controller:None}).unwrap();let dp2 = boot::open_protocol::<DevicePath>(OpenProtocolParams{handle: h2,agent: boot::image_handle(),controller:None}).unwrap();// Do stuff with dp1/dp2...}// Now dp1 and dp2 are dropped.// If dp1 happens to be the same as dp2, the first drop will succeed,// but the second will fail (at least on some firmware), with `Status::NOT_FOUND`.}

I ran into this with real code, where I didn't expect dp1 == dp2. Fortunately I noticed the issue in testing; it would have been bad if the code started panicking in production.

Although my code is fixed, I don't think we should panic here, as it's not a particularly harmful error if close_protocol fails in this case. Some potential changes:

• Remove the panic, or change it to a verbose log (debug! or trace! perhaps)
• Keep the panic, but don't call close_protocol ifGetProtocol is used to open the protocol. Thespec says "The caller is also not required to close the protocol interface with close_protocol" when GET_PROTOCOL is used.
• Keep the panic, but allow either SUCCESS or NOT_FOUND whenGetProtocol is used to open the protocol.