<div style="font-family: Arial, sans-serif; font-size: 14px;"><span>Hello,</span><div><br></div><div><span>I can reproduce this issue on Linux Mint 22.3 (Ubuntu 24.04 Noble base)</span></div><div><span>with LightDM and Cinnamon on X11.</span></div><div><br></div><div><span>The symptom was a black screen with a movable mouse cursor after entering</span></div><div><span>the password in LightDM. The Cinnamon desktop appeared only after</span></div><div><span>approximately 2-3 minutes.</span></div><div><br></div><div><span>The issue was reproducible with a newly-created user account, so it was</span></div><div><span>not caused by per-user Cinnamon configuration.</span></div><div><br></div><div><span>I also tested different kernels and graphics configurations. These did</span></div><div><span>not affect the delay.</span></div><div><br></div><div><span>I instrumented the LightDM session startup and found that the session was</span></div><div><span>blocked waiting for xbrlapi.</span></div><div><br></div><div><span>During the delay the process tree remained:</span></div><div><br></div><div><span> /bin/bash /usr/sbin/lightdm-session cinnamon-session-cinnamon</span></div><div><span> `- /bin/xbrlapi</span></div><div><br></div><div><span>For example, after 132 seconds:</span></div><div><br></div><div><span> USER PID PPID ELAPSED STAT WCHAN CMD</span></div><div><span> bobsyan 1407 1207 132 Ss do_wait /bin/bash /usr/sbin/lightdm-session cinnamon-session-cinnamon</span></div><div><span> bobsyan 1479 1407 132 S wait_woken /bin/xbrlapi</span></div><div><br></div><div><span>At approximately 134 seconds the same state was still present.</span></div><div><br></div><div><span>Immediately afterwards xbrlapi disappeared and PID 1407 exec'd:</span></div><div><br></div><div><span> /usr/lib/x86_64-linux-gnu/cinnamon-session-binary --session cinnamon</span></div><div><br></div><div><span>Cinnamon startup then continued.</span></div><div><br></div><div><span>Disabling the xbrlapi Xsession hook:</span></div><div><br></div><div><span> sudo mv /etc/X11/Xsession.d/90xbrlapi \</span></div><div><span> /etc/X11/Xsession.d/90xbrlapi.disabled</span></div><div><br></div><div><span>completely removed the long login delay.</span></div><div><br></div><div><span>Relevant BRLTTY packages on the system:</span></div><div><br></div><div><span> brltty 6.6-4ubuntu5</span></div><div><span> libbrlapi0.8 6.6-4ubuntu5</span></div><div><br></div><div><span>Another potentially important observation is the behaviour of TCP</span></div><div><span>connections to the BRLAPI port on loopback.</span></div><div><br></div><div><span>IPv4 fails immediately, as expected when nothing is listening:</span></div><div><br></div><div><span> 127.0.0.1: ConnectionRefusedError: [Errno 111] Connection refused, 0.000 s</span></div><div><br></div><div><span>IPv6, however, does not return ECONNREFUSED and instead times out:</span></div><div><br></div><div><span> ::1: TimeoutError: timed out, 5.004 s</span></div><div><br></div><div><span>IPv6 itself is enabled:</span></div><div><br></div><div><span> net.ipv6.conf.all.disable_ipv6 = 0</span></div><div><span> net.ipv6.conf.default.disable_ipv6 = 0</span></div><div><span> net.ipv6.conf.lo.disable_ipv6 = 0</span></div><div><br></div><div><span>There is no ipv6.disable kernel parameter:</span></div><div><br></div><div><span> BOOT_IMAGE=/boot/vmlinuz-7.0.0-31-generic</span></div><div><span> root=UUID=...</span></div><div><span> ro quiet splash</span></div><div><br></div><div><span>This suggests that xbrlapi may attempt the IPv6 loopback connection first</span></div><div><span>and remain blocked by the TCP connect timeout instead of failing quickly.</span></div><div><br></div><div><span>In this case, xbrlapi being started synchronously from the Xsession hook</span></div><div><span>causes the entire graphical desktop session to be delayed for roughly</span></div><div><span>two minutes.</span></div><div><br></div><div><span>Environment:</span></div><div><br></div><div><span> Distribution: Linux Mint 22.3 "Zena"</span></div><div><span> Ubuntu base: 24.04 Noble</span></div><div><span> Desktop: Cinnamon 6.6.9</span></div><div><span> Display manager: LightDM</span></div><div><span> Session type: X11</span></div><div><span> Kernel: 7.0.0-31-generic</span></div><div><span> BRLTTY: 6.6-4ubuntu5</span></div><div><span> libbrlapi0.8: 6.6-4ubuntu5</span></div><div><br></div><div><span>The issue was confirmed by monitoring the LightDM process tree once per</span></div><div><span>second. I have attached the complete monitoring log.</span></div><div><br></div><div><span>The workaround of disabling /etc/X11/Xsession.d/90xbrlapi has been</span></div><div><span>retested and the login delay disappears.</span></div><div><br></div><div><span>Please let me know if additional traces (strace of xbrlapi, nftables</span></div><div><span>rules, LightDM logs, etc.) would be useful.</span></div><div><br></div><div><span>Regards,</span></div><span>Andre</span></div><div style="font-family: Arial, sans-serif; font-size: 14px;"><br></div>
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