[Desktop] Crashes in Adblock Engine

[iefremov]

There is a bunch of similar-looking crashes inside Rust adblocker:

https://brave.sp.backtrace.io/p/brave/triage?time=all&filters=((callstack%2Ccontains%2Crust_panic))&aggregations=((guid%2Cunique)%2C(classifiers%2Chead))

specific example: https://brave.sp.backtrace.io/p/brave/debug?time=all&filters=(_deleted%3D0%2C(callstack%2Ccontains%2Crust_panic))&fingerprint=ca5e3359838d432fd81d41947ce39fed2d38e0a5e560813ad76677b66cfb01f4

...
[ 08 ] _ZN3std7process5abort17h7b0a42a60331a01bE
[ 09 ] rust_panic
[ 10 ] _ZN3std9panicking20rust_panic_with_hook17h1f2449d529a25f22E
[ 11 ] _$LT$adblock..filters..network..NetworkFilter$u20$as$u20$adblock..filters..network..NetworkMatchable$GT$::matches::h57c0d8ed2cbb9c7b
[ 12 ] rust_begin_unwind
[ 13 ] _ZN4core9panicking9panic_fmt17h2c05f81b567d1861E
[ 14 ] _ZN4core6option18expect_none_failed17ha9782a6ef355446fE
[ 15 ] 0x55acbf91fbf0
[ 16 ] 0x55acbf91f9a0
[ 17 ] core::ptr::drop_in_place::ha5bb1979d4cf57bf (.llvm.9443824853129752194)
[ 18 ] adblock::blocker::Blocker::check_parameterised::h0aa7d32f5744fd3c
[ 19 ] adblock::request::Request::from_urls_with_hostname::h7771614cc26ca997
[ 20 ] adblock::request::Request::from_urls_with_hostname::h7771614cc26ca997
[ 21 ] adblock::engine::Engine::check_network_urls_with_hostnames::h7ff76945452fc905
[ 22 ] engine_match
[ 23 ] engine_match
[ 24 ] url::SchemeHostPort::SchemeHostPort(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, unsigned short, url::SchemeHostPort::ConstructPolicy)
[ 25 ] std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >::basic_string(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, unsigned long, unsigned long, std::__1::allocator<char> const&)
[ 26 ] adblock::Engine::matches(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, bool, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, bool*, bool*, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >*)
[ 27 ] std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >::basic_string(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, unsigned long, unsigned long, std::__1::allocator<char> const&)
[ 28 ] brave_shields::AdBlockBaseService::ShouldStartRequest(GURL const&, blink::mojom::ResourceType, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, bool*, bool*, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >*)
[ 29 ] brave_shields::AdBlockBaseService::ShouldStartRequest(GURL const&, blink::mojom::ResourceType, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, bool*, bool*, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >*)
[ 30 ] base::sequence_manager::internal::TaskQueueImpl::TaskRunner::PostDelayedTask(base::Location const&, base::OnceCallback<void ()>, base::TimeDelta)
[ 31 ] brave::OnBeforeURLRequestAdBlockTP(base::RepeatingCallback<void ()> const&, std::__1::shared_ptr<brave::BraveRequestInfo>)
[ 32 ] std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >::basic_string(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, unsigned long, unsigned long, std::__1::allocator<char> const&)
[ 33 ] brave::ShouldBlockAdOnTaskRunner(std::__1::shared_ptr<brave::BraveRequestInfo>)
[ 34 ] base::internal::Invoker<base::internal::BindState<void (*)(std::__1::shared_ptr<brave::BraveRequestInfo>), std::__1::shared_ptr<brave::BraveRequestInfo> >, void ()>::RunOnce(base::internal::BindStateBase*)
[ 35 ] base::(anonymous namespace)::PostTaskAndReplyRelay::RunTaskAndPostReply(base::(anonymous namespace)::PostTaskAndReplyRelay)
[ 36 ] 0x55acc2d0a9d0
[ 37 ] base::internal::Invoker<base::internal::BindState<void (*)(base::(anonymous namespace)::PostTaskAndReplyRelay), base::(anonymous namespace)::PostTaskAndReplyRelay>, void ()>::RunOnce(base::internal::BindStateBase*)
[ 38 ] brave::OnBeforeURLRequestAdBlockTP(base::RepeatingCallback<void ()> const&, std::__1::shared_ptr<brave::BraveRequestInfo>)
[ 39 ] base::TaskAnnotator::RunTask(char const*, base::PendingTask*)
[ 40 ] brave::OnBeforeURLRequestAdBlockTP(base::RepeatingCallback<void ()> const&, std::__1::shared_ptr<brave::BraveRequestInfo>)
[ 41 ] mojo::Connector::PostDispatchNextMessageFromPipe()
[ 42 ] mojo::SimpleWatcher::Context::CallNotify(MojoTrapEvent const*)
[ 43 ] base::internal::TaskTracker::RunSkipOnShutdown(base::internal::Task*)
[ 44 ] base::internal::TaskTracker::RunTask(base::internal::Task, base::internal::TaskSource*, base::TaskTraits const&)
[ 45 ] 0x7ffcf1f85cb8
[ 46 ] 0x7fe5757f9ea6
[ 47 ] brave::OnBeforeURLRequestAdBlockTP(base::RepeatingCallback<void ()> const&, std::__1::shared_ptr<brave::BraveRequestInfo>)
[ 48 ] base::internal::TaskTrackerPosix::RunTask(base::internal::Task, base::internal::TaskSource*, base::TaskTraits const&)

...

This may be related to #10765

[iefremov]

cc @bsclifton to triage
cc @antonok-edm @AndriusA

[iefremov]

Actually it seems that it is only in Nightly and Beta for now, so I think we don't want it to hit Stable
This signature slowly crawled to top20 for browser process https://brave.sp.backtrace.io/p/brave/debug?filters=(_deleted%3D0%2Cptype%3Dbrowser%2C(ver%2Cregex%2C%228%5B1%7C2%7C3%7C4%5D.*%22))&fingerprint=370b9aea74f715763d1dbeea3409d560b13694882456aa0d331935c0e1bfabe5&debug=(%224be05%22,0,0)

[iefremov]

Ok, I think I've found the cause: apparently, AdBlockBaseService::UrlCosmeticResources and AdBlockBaseService::HiddenClassIdSelectors should not be called from UI thread, since ad_block_client_ lives on the custom taskrunner