1585801 - Crash in [@ core::result::unwrap_failed<T> | webrender::render_backend::RenderBackend::run]

Status: RESOLVED FIXED

(Core :: Graphics: WebRender, defect, P2)

Description

[Marcia Knous [:marcia]]

This bug is for crash report bp-fb9db9ae-c989-40dc-9759-617290190930.

Seen while looking at nightly crash stats - crashes started in 20190927215713: https://bit.ly/2nMFt8e.

Moz crash reason: called Result::unwrap() on an Err value: Os { code: 5, kind: PermissionDenied, message: "Zugriff verweigert" }

Top 10 frames of crashing thread:

0 xul.dll GeckoCrash toolkit/xre/nsAppRunner.cpp:5117
1 xul.dll static void gkrust_shared::panic_hook toolkit/library/rust/shared/lib.rs:248
2 xul.dll static void core::ops::function::Fn::call<fn src/libcore/ops/function.rs:69
3 xul.dll static void std::panicking::rust_panic_with_hook src/libstd/panicking.rs:481
4 xul.dll static void std::panicking::continue_panic_fmt src/libstd/panicking.rs:384
5 xul.dll static void std::panicking::rust_begin_panic src/libstd/panicking.rs:311
6 xul.dll static void core::panicking::panic_fmt src/libcore/panicking.rs:85
7 xul.dll static <NoType> core::result::unwrap_failed<std::io::error::Error> src/libcore/macros.rs:18
8 xul.dll static void webrender::render_backend::RenderBackend::run gfx/wr/webrender/src/render_backend.rs
9  @0x1f1fdc94c6f 

Comment 1

[Jessie [:jbonisteel] pls NI]

Jeff, could this be related to: Bug 1582645

Comment 2

[Jeff Muizelaar [:jrmuizel]]

The stacks from this crash are not really very useful because we don't know which unwrap is failing. See https://github.com/rust-lang/rust/issues/63105 for why and a possible solution.

Comment 3

[Jeff Muizelaar [:jrmuizel]]

It is notable that we're unwraping this result though:
called Result::unwrap() on an Err value: Os { code: 5, kind: PermissionDenied, message: "Access is denied." }

Perhaps that can help us narrow down where the crash is happening.

Comment 4

[Jeff Muizelaar [:jrmuizel]]

I believe this was caused by bug 1582565

Comment 5

[Kris Taeleman (:ktaeleman)]

Attachment: Bug 1585801 - Fixing crash when folder is not writable and refactored logic.

Comment 6

[BugBot [:suhaib / :marco/ :calixte]]

:kris, since this bug is a regression, could you fill (if possible) the regressed_by field?
For more information, please visit auto_nag documentation.

Comment 7

[Marcia Knous [:marcia]]

Hello Kris - if this fix is approved, can we get it checked in? Thanks.

Comment 8

[Kris Taeleman (:ktaeleman)]

d

Comment 9

[Kris Taeleman (:ktaeleman)]

Yes, @jrmuizel, could you land https://phabricator.services.mozilla.com/D48999?

Comment 10

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/5506d1803e15
Fixing crash when folder is not writable and refactored logic. r=jrmuizel

Comment 11

[Cosmin Sabou [:CosminS]]

https://hg.mozilla.org/mozilla-central/rev/5506d1803e15

Comment 12

[Anca Soncutean, Desktop QA]

Is there something here that could be covered by the manual QA, some steps maybe? Thank you!

Comment 13

[Kris Taeleman (:ktaeleman)]

This is a nightly only development feature.
Pressing ctrl + shift + 5 toggles logging of transactions sent to webrender into a file in the workspace folder of firefox. (wr-log-[date].log)

The issue here was that when this path was not writeable (ex. Installation in Program Files) the application would crash and keep crashing at startup as the preference flag enabling the feature was not cleared.

In the patch for this fix, the implementation was changed to only use the shortcut and the preference was removed. Extra safeguards were also put in place that handle not being able to write to the file.

Comment 14

[Anca Soncutean, Desktop QA]

(In reply to Kris Taeleman (:kris/kris) from comment #13)

This is a nightly only development feature.

Thank you for your time, since this is Nightly only I will not set the qe+ as part of 71 Beta bug verification!