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<b><a class="bz_bug_link
bz_status_NEW "
title="NEW - [CI] igt@* - Incomplete - INFO: task [gem_tiled_swapp|kms_flip] blocked for more than 60 seconds."
href="https://bugs.freedesktop.org/show_bug.cgi?id=103525#c4">Comment # 4</a>
on <a class="bz_bug_link
bz_status_NEW "
title="NEW - [CI] igt@* - Incomplete - INFO: task [gem_tiled_swapp|kms_flip] blocked for more than 60 seconds."
href="https://bugs.freedesktop.org/show_bug.cgi?id=103525">bug 103525</a>
from <span class="vcard"><a class="email" href="mailto:daniel@ffwll.ch" title="Daniel Vetter <daniel@ffwll.ch>"> <span class="fn">Daniel Vetter</span></a>
</span></b>
<pre>I looked at the 2 examples linked, and the common issue seems to be that we're
stuck somewhere in the uart transmit, within printk, which can be called from
anywhere and so block any other task.
So either the serial console can't keep up, or it's broken.
Example backtrace:
<4>[ 553.954347] Call Trace:
<4>[ 553.954348] wait_for_xmitr+0x41/0xa0
<4>[ 553.954348] serial8250_console_putchar+0x1c/0x30
<4>[ 553.954348] ? wait_for_xmitr+0xa0/0xa0
<4>[ 553.954348] uart_console_write+0x30/0x70
<4>[ 553.954348] serial8250_console_write+0xd9/0x270
<4>[ 553.954349] ? vt_console_print+0x225/0x3b0
<4>[ 553.954349] ? msg_print_text+0x9d/0x100
<4>[ 553.954349] univ8250_console_write+0x26/0x30
<4>[ 553.954349] console_unlock+0x430/0x570
<4>[ 553.954350] vprintk_emit+0x254/0x3b0
<4>[ 553.954350] ? wake_up_q+0x59/0x80
<4>[ 553.954350] vprintk_default+0x1f/0x30
<4>[ 553.954350] vprintk_func+0x2c/0x90
<4>[ 553.954351] printk+0x43/0x4b
above is the common part that would identify this bug, below can vary depending
upon who's stuck and why:
<4>[ 553.954351] ? drm_helper_hpd_irq_event+0xcc/0x110
<4>[ 553.954351] drm_printk+0x8e/0x90
<4>[ 553.954351] drm_helper_hpd_irq_event+0xcc/0x110
<4>[ 553.954352] i915_hpd_poll_init_work+0xc5/0x100 [i915]
<4>[ 553.954352] process_one_work+0x221/0x650
<4>[ 553.954352] worker_thread+0x4e/0x3c0
<4>[ 553.954352] kthread+0x114/0x150
<4>[ 553.954352] ? process_one_work+0x650/0x650
<4>[ 553.954353] ? kthread_create_on_node+0x40/0x40
<4>[ 553.954353] ret_from_fork+0x27/0x40</pre>
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