Re: Debugging system freezes on filesystem writes

From: Marcus Sundman
Date: Wed Feb 20 2013 - 06:40:34 EST

On 20.02.2013 10:42, Marcus Sundman wrote:
On 05.12.2012 17:32, Jan Kara wrote:
I see. Maybe you could have something like
while true; do echo w >/proc/sysrq-trigger; sleep 10; done
running in the background?

Sure, but I suspect it'll take until the worst is over before it manages to load and execute that "echo w".

Here is a big run of sysrq-triggering, all while I was uncompressing a big rar file causing the whole system to be utterly unusable.
NB: Even with realtime I/O-priority the sysrq couldn't be triggered between 12:41:54 and 12:42:49, as you can see from the dmesg-3.txt file.

$ sudo ionice -c 1 su
# ionice
realtime: prio 4
# while true; do sleep 10; echo w >/proc/sysrq-trigger; done
# tail -n +1700 /var/log/syslog >dmesg-3.txt

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