On Tue, Apr 02, 2024 at 12:34:14PM +0200, Sebastian Andrzej Siewior wrote: > > Just before the sysrq that crashes the system. > > so this is intentional. Yes. > > > > This is part of the console_blast.sh script that John Ogness sent me. > > > > Please see below: > … > > Okay. Then everything works as it should… Correct. > > > > > NMI Backtrace for 6.6.20-rt25 no forced preemption with tuned throughput-performance profile > > > > ----------------------------- > > > > > > This and the following backtrace shows the same picture: The CPU is > > > crashing due to proc/sysrq request and does CPU-backtraces via NMI and > > > polls in early_printk, waiting for the UART to become idle (probably). > > > > > > I don't see an issue here so far. > > > > Luis Goncalves discussed it with me after reading your response. Thank > > you for your help. The NMI was needed to flush the buffers upon the > > system crashing itself. Does this part about NMI watchdog need to be > > documented? > > Not sure about that one. There is an _a_ _lot_ to be printed from NMI > and the NMI watchdog might trigger if nothing is triggering the > NMI-watchdog during the print job. Also, the crash was requested. I reran the 6.6 test and no NMI was reported with fully preemptive and the realtime tuned profile. It was my error; my apologies for that. I did include more of logs if you want to see here for my 6.8 testing. https://lore.kernel.org/linux-rt-users/ZgWL2UyknaE2T70C@thinkpad2021/T/#u Sincerely, John Wyatt Software Engineer, Core Kernel Red Hat
