[SMAGENT-2066] Control driver printing when in interrupt context #1522
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A customer reported an issue where the driver would deadlock the system by attempting to printk() while the schedule lock is already held due to a context switch. This occurred because the context switch triggered a deferred drop_x event, which prints a log message when it's processed. Printing the log message caused the framebuffer helper in the console print driver to attempt a context switch and hang the system on the schedule lock. This is a rare event, as it requires the kernel console log level to be set to ERROR or above and for a print to occur while processing a context switch tracepoint.
gnosek
approved these changes
Oct 22, 2019
adalton
approved these changes
Oct 22, 2019
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A customer reported an issue where the driver would deadlock the system
by attempting to printk() while the schedule lock is already held due to
a context switch. This occurred because the context switch triggered a
deferred drop_x event, which prints a log message when it's processed.
Printing the log message caused the framebuffer helper in the console
print driver to attempt a context switch and hang the system on the
schedule lock.
This is a rare event, as it requires the kernel console log level to be
set to ERROR or above and for a print to occur while processing a
context switch tracepoint.