brave://adblock crashes browser after interaction from multiple tabs

[antonok-edm]

Using the following steps, I can get a 100% reproducible crash:

• Open brave://adblock in a new tab
• Open brave://adblock in a second new tab
• Enable any filter list in the first tab
• Enable the same filter list in the second tab

Ideally, toggling a filter list would update all open brave://adblock tabs, like how it works with brave://settings. At the very least, it should not crash the entire browser.

Crash occurs at:

[FATAL:ad_block_regional_service_manager.cc(181)] Check failed: it != regional_services_.end().

[iefremov]

people encounter it in the wild https://brave.sp.backtrace.io/p/brave/explore?time=month&filters=((callstack.functions%2Ccontains%2CBraveComponent)%2C_deleted%3D0%2C(ver%2Cregex%2C%2290%7C91.*%22)%2Cptype%3Dbrowser)&aggregations=((channel%2Cdistribution)%2C(ver%2Cmax)%2C(ver%2Cmin)%2C(ver%2Cdistribution%2C3)%2C(callstack%2Chead))&

[ 00 ] brave_component_updater::BraveComponent::Unregister()
[ 01 ] brave_component_updater::BraveComponent::Unregister()
[ 02 ] brave_shields::AdBlockRegionalServiceManager::EnableFilterList(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, bool)
[ 03 ] (anonymous namespace)::AdblockDOMHandler::HandleEnableFilterList(base::ListValue const*)
[ 04 ] content::mojom::WebUIHostStubDispatch::Accept(content::mojom::WebUIHost*, mojo::Message*)

[antonok-edm]

Ideally, the brave://adblock UI should use the JS prefs API to update adblock settings, and it should have an observer to listen for changes. The adblock services should also be updated through a pref observer.

[goodov]

it currently crashes in a slightly different way #31561

[kjozwiak]

The above requires 1.57.52 or higher for 1.57.x verification 👍

[Uni-verse]

Verified on Samsung Galaxy Tab S7 using the following version(s):

Brave	1.57.53 Chromium: 116.0.5845.114 (Official Build) (64-bit) 
Revision	b7a154dc9e27b02528cb2cfc8010d8edf1e35571
OS	Android 13; Build/TP1A.220624.014; 33; REL

• Verified STR in brave://adblock crashes browser after interaction from multiple tabs #14123 (comment)
• Verified that browser does not crash when applying the same filter lists in brave://adblock on multiple tabs

First Tab	Second Tab	Tab View

[Uni-verse]

Verified on Samsung Galaxy S21 5G using the following version(s):

Brave	1.57.53 Chromium: 116.0.5845.114 (Official Build) (64-bit) 
Revision	b7a154dc9e27b02528cb2cfc8010d8edf1e35571
OS	Android 13; Build/TP1A.220624.014; 33; REL

• Verified STR in brave://adblock crashes browser after interaction from multiple tabs #14123 (comment)
• Verified that browser does not crash when applying the same filter lists in brave://adblock on multiple tabs