1543495 - Crash in [@ mozilla::ipc::IPDLParamTraits<T>::Write] when (aVar).get_PChildToParentStreamChild()) is null

Status: RESOLVED WORKSFORME

(Core :: DOM: Core & HTML, defect)

Description

[Andrew McCreight [:mccr8]]

This bug is for crash report bp-e57de2e0-70fb-4525-83d1-e65e20190306.

Top 10 frames of crashing thread:

0 xul.dll static void mozilla::ipc::IPDLParamTraits<mozilla::ipc::IPCRemoteStreamType>::Write ipc/ipdl/InputStreamParams.cpp:924
1 xul.dll static void mozilla::ipc::IPDLParamTraits<mozilla::ipc::IPCRemoteStreamParams>::Write ipc/ipdl/InputStreamParams.cpp:1135
2 xul.dll static void mozilla::ipc::IPDLParamTraits<mozilla::ipc::InputStreamParams>::Write ipc/ipdl/InputStreamParams.cpp:2069
3 xul.dll mozilla::ipc::IPDLParamTraits<mozilla::ipc::IPCStream>::Write ipc/ipdl/IPCStream.cpp:45
4 xul.dll mozilla::ipc::IPDLParamTraits<mozilla::Maybe<mozilla::ipc::IPCStream> >::Write ipc/glue/IPDLParamTraits.h:188
5 xul.dll static void mozilla::ipc::IPDLParamTraits<mozilla::dom::cache::CacheReadStream>::Write ipc/ipdl/CacheTypes.cpp:184
6 xul.dll static void mozilla::ipc::IPDLParamTraits<mozilla::dom::cache::CacheReadStreamOrVoid>::Write ipc/ipdl/CacheTypes.cpp:548
7 xul.dll static void mozilla::ipc::IPDLParamTraits<mozilla::dom::cache::CacheResponse>::Write ipc/ipdl/CacheTypes.cpp:1416
8 xul.dll static void mozilla::ipc::IPDLParamTraits<mozilla::dom::cache::CacheRequestResponse>::Write ipc/ipdl/CacheTypes.cpp:1960
9 xul.dll static void mozilla::ipc::IPDLParamTraits<nsTArray<mozilla::dom::cache::CacheRequestResponse> >::WriteInternal<const nsTArray<mozilla::dom::cache::CacheRequestResponse>&> ipc/glue/IPDLParamTraits.h:165

I'm looking over crashes with the signature [@ mozilla::ipc::IPDLParamTraits<T>::Write]. The most common one is where we're crashing on this:
MOZ_RELEASE_ASSERT((aVar).get_PChildToParentStreamChild()) (NULL actor value passed to non-nullable param)

The odd thing is that this crash only affects 66 and earlier. In fact, I went back and looked at old crash reports, and the linked report here seems to be the last build where this crash showed up on Nightly, 20190304215035. There were later builds of 67 Nightly that had crashes, but not this one. So something must have fixed it, or the crash changed somehow.

If that really is the last affected build, then something in here fixed it: https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=8602628e7edaecadea855a64179b329da6ff1f20&tochange=78601cacfe69dc8659c3fe7cd3eb94366aa3d680

Nothing jumps out at me. Anyways, it isn't like we're going to backport a fix for this to 66, so I guess there's not anything to do here, but I wanted to file this in case it helped shed light on anything.

Comment 1

[Andrew McCreight [:mccr8]]

The IPC types involved here have changed in a few ways since the crash last occurred, but none of them landed around 3-4 AFAICT.

Comment 2

[Andrew McCreight [:mccr8]]

[@ mozilla::ipc::WriteIPDLParam<T> ] is another signature for the same release assert: bp-8133f28a-67f5-4c52-bfc4-9b66f0190328