Mibbit IRC doesn't work

[leoschwarz]

1. Launch servo ./mach run "https://chat.mibbit.com/?server=irc.mozilla.org&channel=%23rust"
2. Click the "go" button and wait. (<10s in release mode, <2min in dev mode)

Leads to Servo freezing/crashing and output similar to: Release • Debug

[jdm]

I haven't even seen anything besides a gray screen rendered in a debug build. Very peculiar.

[jdm]

The grey screen is caused by #15017 and the fact that Servo (and presumably the version of openSSL that I'm using) can't connect to mibbit's HTTPS server - it claims an unexpected EOF occurs during the handshake.

[jdm]

On a different machine I can reproduce this problem. A backtrace from a debug build shows me:

ERROR:servo: called `Result::unwrap()` on an `Err` value: Error { repr: Os { code: 24, message: "Too many open files" } }
Pipeline layout content shutdown chan: Error { repr: Os { code: 24, message: "Too many open files" } } (thread Constellation, at /buildslave/rust-buildbot/slave/nightly-dist-rustc-linux/build/src/libcore/result.rs:845)
[Switching to Thread 0x7fffe75ff700 (LWP 12209)]

Thread 25 "ScriptThread Pi" hit Breakpoint 1, std::panicking::rust_panic () at /buildslave/rust-buildbot/slave/nightly-dist-rustc-linux/build/src/libstd/panicking.rs:586
586	/buildslave/rust-buildbot/slave/nightly-dist-rustc-linux/build/src/libstd/panicking.rs: No such file or directory.
(gdb) bt
#0  std::panicking::rust_panic () at /buildslave/rust-buildbot/slave/nightly-dist-rustc-linux/build/src/libstd/panicking.rs:586
#1  0x000055555afb71cd in std::panicking::rust_panic_with_hook () at /buildslave/rust-buildbot/slave/nightly-dist-rustc-linux/build/src/libstd/panicking.rs:571
#2  0x000055555afb6fa5 in std::panicking::begin_panic<collections::string::String> () at /buildslave/rust-buildbot/slave/nightly-dist-rustc-linux/build/src/libstd/panicking.rs:517
#3  0x000055555afb6f1a in std::panicking::begin_panic_fmt () at /buildslave/rust-buildbot/slave/nightly-dist-rustc-linux/build/src/libstd/panicking.rs:501
#4  0x000055555afb6ea8 in std::panicking::rust_begin_panic () at /buildslave/rust-buildbot/slave/nightly-dist-rustc-linux/build/src/libstd/panicking.rs:477
#5  0x000055555afe43be in core::panicking::panic_fmt () at /buildslave/rust-buildbot/slave/nightly-dist-rustc-linux/build/src/libcore/panicking.rs:69
#6  0x000055555996f9ff in core::result::unwrap_failed<std::io::error::Error> (msg="called `Result::unwrap()` on an `Err` value", error=Error = {...})
    at /buildslave/rust-buildbot/slave/nightly-dist-rustc-linux/build/src/libcore/macros.rs:29
#7  0x0000555559961011 in core::result::{{impl}}::unwrap<(ipc_channel::ipc::IpcSender<core::result::Result<net_traits::image_cache_thread::ImageOrMetadataAvailable, net_traits::image_cache_thread::ImageState>>, ipc_channel::ipc::IpcReceiver<core::result::Result<net_traits::image_cache_thread::ImageOrMetadataAvailable, net_traits::image_cache_thread::ImageState>>),std::io::error::Error> (self=Err = {...})
    at /buildslave/rust-buildbot/slave/nightly-dist-rustc-linux/build/src/libcore/result.rs:745
#8  0x00005555599a7b70 in net_traits::image_cache_thread::{{impl}}::find_image_or_metadata (self=0x7fffe5630dc0, url=ServoUrl = {...}, use_placeholder=Yes, can_request=Yes)
    at /home/jdm/master-servo/components/net_traits/image_cache_thread.rs:132
Python Exception <class 'ValueError'> invalid literal for int() with base 0: '0x7fffd05f6b30 "https://s3.amazonaws.com/mibbit/gfx/user.png"': 
#9  0x0000555558a724b9 in script::dom::htmlimageelement::{{impl}}::update_image (self=0x7fffd05baf00, value=...) at /home/jdm/master-servo/components/script/dom/htmlimageelement.rs:285
#10 0x0000555558a75362 in script::dom::htmlimageelement::{{impl}}::attribute_mutated (self=0x7fffd05baf00, attr=0x7fffd020df80, mutation=Set = {...})
    at /home/jdm/master-servo/components/script/dom/htmlimageelement.rs:581
#11 0x00005555589fb530 in script::dom::element::{{impl}}::push_attribute (self=0x7fffd05baf00, attr=0x7fffd020df80) at /home/jdm/master-servo/components/script/dom/element.rs:961
#12 0x00005555589fb1da in script::dom::element::{{impl}}::push_new_attribute (self=0x7fffd05baf00, local_name=Atom<html5ever_atoms::LocalNameStaticSet> = {...}, value=String = {...}, 
    name=Atom<html5ever_atoms::LocalNameStaticSet> = {...}, namespace=Atom<html5ever_atoms::NamespaceStaticSet> = {...}, prefix=None) at /home/jdm/master-servo/components/script/dom/element.rs:953
#13 0x00005555589fdc71 in script::dom::element::{{impl}}::set_first_matching_attribute<closure> (self=0x7fffd05baf00, local_name=Atom<html5ever_atoms::LocalNameStaticSet> = {...}, value=String = {...}, 
    name=Atom<html5ever_atoms::LocalNameStaticSet> = {...}, namespace=Atom<html5ever_atoms::NamespaceStaticSet> = {...}, prefix=None, find=closure = {...})
    at /home/jdm/master-servo/components/script/dom/element.rs:1052
#14 0x00005555589fc7d5 in script::dom::element::{{impl}}::set_attribute (self=0x7fffd05baf00, name=0x7fffe75f5790, value=String = {...}) at /home/jdm/master-servo/components/script/dom/element.rs:1006
#15 0x0000555558a01767 in script::dom::element::{{impl}}::set_string_attribute (self=0x7fffd05baf00, local_name=0x7fffe75f5790, value=DOMString = {...})
    at /home/jdm/master-servo/components/script/dom/element.rs:1159
#16 0x0000555559301a0a in script::dom::htmlimageelement::{{impl}}::SetSrc (self=0x7fffd05baf00, value=DOMString = {...}) at /home/jdm/master-servo/components/script/dom/htmlimageelement.rs:459
#17 0x0000555558f68151 in script::dom::bindings::codegen::Bindings::HTMLImageElementBinding::HTMLImageElementBinding::set_src::{{closure}} () at /home/jdm/master-servo/components/script/dom/bindings/mod.rs:164
#18 0x000055555932edf9 in core::ops::FnOnce::call_once::h21e82ffe8bd419f8 ()
#19 0x00005555587c2beb in std::panic::{{impl}}::call_once<bool,closure> (self=AssertUnwindSafe<closure> = {...}, _args=0) at /buildslave/rust-buildbot/slave/nightly-dist-rustc-linux/build/src/libstd/panic.rs:296
#20 0x0000555557e82a4d in std::panicking::try::do_call<std::panic::AssertUnwindSafe<closure>,bool> (data=0x7fffe75f5ca0 "\310^_\347\377\177")
    at /buildslave/rust-buildbot/slave/nightly-dist-rustc-linux/build/src/libstd/panicking.rs:460
#21 0x000055555afbe09b in panic_unwind::__rust_maybe_catch_panic () at /buildslave/rust-buildbot/slave/nightly-dist-rustc-linux/build/src/libpanic_unwind/lib.rs:98
#22 0x0000555557d380d5 in std::panicking::try<bool,std::panic::AssertUnwindSafe<closure>> (f=AssertUnwindSafe<closure> = {...})
    at /buildslave/rust-buildbot/slave/nightly-dist-rustc-linux/build/src/libstd/panicking.rs:436
#23 0x0000555557b65c2a in std::panic::catch_unwind<std::panic::AssertUnwindSafe<closure>,bool> (f=AssertUnwindSafe<closure> = {...})
    at /buildslave/rust-buildbot/slave/nightly-dist-rustc-linux/build/src/libstd/panic.rs:361
#24 0x000055555758da5e in js::panic::wrap_panic<std::panic::AssertUnwindSafe<closure>,bool> (function=AssertUnwindSafe<closure> = {...}, generic_return_type=false)
    at /home/jdm/master-servo/.cargo/git/checkouts/rust-mozjs-8611526964119dd6/15ff1e8/src/panic.rs:22
#25 0x0000555558f67e72 in script::dom::bindings::codegen::Bindings::HTMLImageElementBinding::HTMLImageElementBinding::set_src (cx=0x7fffeb4c8c40, obj=Handle<*mut js::jsapi::JSObject> = {...}, 
    this=0x7fffd05baf00, args=JSJitSetterCallArgs = {...}) at /home/jdm/master-servo/components/script/dom/bindings/mod.rs:164
#26 0x00007fffedd28494 in ?? ()
#27 0x000055555d445100 in ?? ()
#28 0x00007fffe75f5f30 in ?? ()
#29 0x0000000000000000 in ?? ()
(gdb) 

[jdm]

The reason that the backtrace always shows a "Too many files" error under HTMLImageElement::SetSrc is that the page ends up creating image elements and loading https://s3.amazonaws.com/mibbit/gfx/mode_none.png and https://s3.amazonaws.com/mibbit/gfx/user.png until the end of time. Each time we set the source of an image we create a new IPC channel in order to communicate with the image cache thread, which consumes a file descriptor.

[ferjm]

This seems to be fixed after #15701 was fixed