Direct leak of 784 byte(s) in 25 object(s) allocated from:
    #0 __interceptor_realloc /builds/worker/workspace/moz-toolchain/src/llvm/projects/compiler-rt/lib/asan/asan_malloc_linux.cc:165:3
    #1 std::sys::unix::alloc::_$LT$impl$u20$core..alloc..GlobalAlloc$u20$for$u20$std..alloc..System$GT$::realloc::h8df3ca51ecd89c35 /rustc/a53f9df32fbb0b5f4382caaad8f1a46f36ea887c/src/libstd/sys/unix/alloc.rs:43:12
    #2 __rdl_realloc /rustc/a53f9df32fbb0b5f4382caaad8f1a46f36ea887c/src/libstd/alloc.rs:255
    #3 alloc::alloc::realloc::h4bc5231c2b89109d /rustc/a53f9df32fbb0b5f4382caaad8f1a46f36ea887c/src/liballoc/alloc.rs:125
    #4 _$LT$alloc..alloc..Global$u20$as$u20$core..alloc..Alloc$GT$::realloc::hc52e0fe907a4f7ff /rustc/a53f9df32fbb0b5f4382caaad8f1a46f36ea887c/src/liballoc/alloc.rs:184
    #5 alloc::raw_vec::RawVec$LT$T$C$A$GT$::reserve_internal::h0f60d175b1d96be6 /rustc/a53f9df32fbb0b5f4382caaad8f1a46f36ea887c/src/liballoc/raw_vec.rs:666
    #6 alloc::raw_vec::RawVec$LT$T$C$A$GT$::reserve::h462d547446b8d0da /rustc/a53f9df32fbb0b5f4382caaad8f1a46f36ea887c/src/liballoc/raw_vec.rs:491
    #7 alloc::vec::Vec$LT$T$GT$::reserve::h80908fd58db99fb4 /rustc/a53f9df32fbb0b5f4382caaad8f1a46f36ea887c/src/liballoc/vec.rs:457
    #8 alloc::vec::Vec$LT$T$GT$::push::h1831bb6d57a6f575 /rustc/a53f9df32fbb0b5f4382caaad8f1a46f36ea887c/src/liballoc/vec.rs:1033
    #9 cssparser::parser::Parser::parse_comma_separated::h123ca9da6d07dde9 src/third_party/rust/cssparser/src/parser.rs:664
    #10 selectors::parser::parse_compound_selector_list::h5fff3e15153e4b80 src/servo/components/selectors/parser.rs:366
    #11 style::gecko::selector_parser::_$LT$impl$u20$selectors..parser..Parser$u20$for$u20$style..selector_parser..SelectorParser$GT$::parse_non_ts_functional_pseudo_class::h4032fb7efce96897 src/servo/components/style/gecko/selector_parser.rs:396
    #12 selectors::parser::parse_functional_pseudo_class::h271a74eaea99b1b2 src/servo/components/selectors/parser.rs:2091:4
    #13 selectors::parser::parse_one_simple_selector::_$u7b$$u7b$closure$u7d$$u7d$::h2cd9602cee317f5a src/servo/components/selectors/parser.rs:2228:24
    #14 cssparser::parser::Parser::parse_entirely::hbade9ccddc7f31ef src/third_party/rust/cssparser/src/parser.rs:634
    #15 cssparser::parser::parse_nested_block::hfeb631773c0028b3 src/third_party/rust/cssparser/src/parser.rs:1048
    #16 cssparser::parser::Parser::parse_nested_block::h3171e60ec05e3e6d src/third_party/rust/cssparser/src/parser.rs:689
    #17 selectors::parser::parse_one_simple_selector::hf0e18ae21c362c82 src/servo/components/selectors/parser.rs:2227
    #18 selectors::parser::parse_compound_selector::h5959fb63c55dd863 src/servo/components/selectors/parser.rs:2021:33
    #19 selectors::parser::parse_selector::hdab9a42487b8346a src/servo/components/selectors/parser.rs:1486
    #20 selectors::parser::SelectorList$LT$Impl$GT$::parse::_$u7b$$u7b$closure$u7d$$u7d$::h5add13127df4660d src/servo/components/selectors/parser.rs:315:66
    #21 cssparser::parser::Parser::parse_entirely::h99dfa992a56d6aac src/third_party/rust/cssparser/src/parser.rs:634
    #22 cssparser::parser::parse_until_before::hc2d3b2fcb1835f65 src/third_party/rust/cssparser/src/parser.rs:975
    #23 cssparser::parser::Parser::parse_until_before::hc08548621fa4cee4 src/third_party/rust/cssparser/src/parser.rs:709
    #24 selectors::parser::SelectorList$LT$Impl$GT$::parse::hef6b1101bc1aff45 src/servo/components/selectors/parser.rs:314
    #25 _$LT$style..stylesheets..rule_parser..NestedRuleParser$u20$as$u20$cssparser..rules_and_declarations..QualifiedRuleParser$GT$::parse_prelude::h5f7c7a911c36232f src/servo/components/style/stylesheets/rule_parser.rs:587:8
    #26 _$LT$style..stylesheets..rule_parser..TopLevelRuleParser$u20$as$u20$cssparser..rules_and_declarations..QualifiedRuleParser$GT$::parse_prelude::ha81f857b5a875c4f src/servo/components/style/stylesheets/rule_parser.rs:312
    #27 cssparser::rules_and_declarations::parse_qualified_rule::_$u7b$$u7b$closure$u7d$$u7d$::hedb1684a268a69d2 src/third_party/rust/cssparser/src/rules_and_declarations.rs:538
    #28 cssparser::parser::Parser::parse_entirely::hac4daaa128929e27 src/third_party/rust/cssparser/src/parser.rs:634
    #29 cssparser::parser::parse_until_before::h8508aec81e8b7511 src/third_party/rust/cssparser/src/parser.rs:975
    #30 cssparser::rules_and_declarations::parse_qualified_rule::h122ac9b536d572ca src/third_party/rust/cssparser/src/rules_and_declarations.rs:537
    #31 _$LT$cssparser..rules_and_declarations..RuleListParser$LT$P$GT$$u20$as$u20$core..iter..traits..iterator..Iterator$GT$::next::h3a22d692d353bd85 src/third_party/rust/cssparser/src/rules_and_declarations.rs:415:29
    #32 style::stylesheets::stylesheet::Stylesheet::parse_rules::h30786c53c660c954 src/servo/components/style/stylesheets/stylesheet.rs:418
    #33 style::stylesheets::stylesheet::StylesheetContents::from_str::hd9f0aeea75b2558a src/servo/components/style/stylesheets/stylesheet.rs:86
    #34 Servo_StyleSheet_FromUTF8Bytes src/servo/ports/geckolib/glue.rs:1391:13
    #35 mozilla::StyleSheet::ParseSheetSync(mozilla::css::Loader*, nsTSubstring<char> const&, mozilla::css::SheetLoadData*, unsigned int, mozilla::css::LoaderReusableStyleSheets*) src/layout/style/StyleSheet.cpp:1004:7
    #36 mozilla::css::Loader::ParseSheet(nsTSubstring<char> const&, mozilla::css::SheetLoadData*, mozilla::css::Loader::AllowAsyncParse) src/layout/style/Loader.cpp:1549:12
    #37 mozilla::css::StreamLoader::OnStopRequest(nsIRequest*, nsresult) src/layout/style/StreamLoader.cpp:109:28
    #38 nsSyncLoadService::PushSyncStreamToListener(already_AddRefed<nsIInputStream>, nsIStreamListener*, nsIChannel*) src/dom/base/nsSyncLoadService.cpp:362:14
    #39 mozilla::css::Loader::LoadSheet(mozilla::css::SheetLoadData*, mozilla::css::StyleSheetState, bool) src/layout/style/Loader.cpp:1303:12
    #40 mozilla::css::Loader::InternalLoadNonDocumentSheet(nsIURI*, bool, mozilla::css::SheetParsingMode, bool, nsIPrincipal*, mozilla::Encoding const*, RefPtr<mozilla::StyleSheet>*, nsIReferrerInfo*, nsICSSLoaderObserver*, mozilla::CORSMode, nsTSubstring<char16_t> const&) src/layout/style/Loader.cpp:2200:8
    #41 mozilla::css::Loader::LoadSheetSync(nsIURI*, mozilla::css::SheetParsingMode, bool, RefPtr<mozilla::StyleSheet>*) src/layout/style/Loader.cpp:2112:10
    #42 nsLayoutStylesheetCache::LoadSheet(nsIURI*, RefPtr<mozilla::StyleSheet>*, mozilla::css::SheetParsingMode, mozilla::css::FailureAction) src/layout/style/nsLayoutStylesheetCache.cpp:519:29
    #43 LoadSheetURL src/layout/style/nsLayoutStylesheetCache.cpp:460:3
    #44 nsLayoutStylesheetCache::HTMLSheet() src/obj-firefox/dist/include/mozilla/UserAgentStyleSheetList.h:27
    #45 mozilla::dom::Document::FillStyleSetUserAndUASheets() src/dom/base/Document.cpp:2644:62
    #46 FillStyleSet src/dom/base/Document.cpp:2684:3
    #47 mozilla::dom::Document::CreatePresShell(nsPresContext*, nsViewManager*) src/dom/base/Document.cpp:5921

User-agent stylesheets are static, so they should go away as soon as nsLayoutStyleSheetCache::ShutDown() is called, and other documents don't reference them.

Maybe in this case we're keeping the stylesheets in the document for too long and are leaking the document somehow?

BloatView log

This is leaking a window.

The priority flag is not set for this bug.
:hiro, could you have a look please?

For more information, please visit auto_nag documentation.

Moving to DOM:Core & HTML as per comment 3.