[webkit-changes] [WebKit/WebKit] 413b2a: [GTK] Race condition when reading the display numb...

[Carlos Alberto Lopez Perez]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: 413b2a19f079979ab5a0842b86f7e82ae3cb508f
      https://github.com/WebKit/WebKit/commit/413b2a19f079979ab5a0842b86f7e82ae3cb508f
  Author: Carlos Alberto Lopez Perez <clopez at igalia.com>
  Date:   2023-09-20 (Wed, 20 Sep 2023)

  Changed paths:
    M Tools/Scripts/webkitpy/port/xvfbdriver.py

  Log Message:
  -----------
  [GTK] Race condition when reading the display number from Xvfb
https://bugs.webkit.org/show_bug.cgi?id=261093

Reviewed by Carlos Garcia Campos.

When we read the display number from Xvfb with the `-displayfd`
parameter via a shared pipe we need to wait until Xvfb writes
the EOL before closing the pipe or we may end in a race condition
where we close this pipe and then later Xvfb crashes when trying
to write the EOL to a file descriptor that is not longer valid.

This was causing random crashes on the layout tests related with
Xvfb exiting with error.

* Tools/Scripts/webkitpy/port/xvfbdriver.py:
(XvfbDriver._xvfb_pipe):
(XvfbDriver._xvfb_read_display_id):
(XvfbDriver._xvfb_run):
(XvfbDriver._xvfb_stop):
(XvfbDriver._xvfb_check_if_ready):
(XvfbDriver._start_and_check_xvfb):
(XvfbDriver.has_crashed):

Canonical link: https://commits.webkit.org/268189@main