On Wed, 23 Apr 2014, Andrew Morton wrote: > > Echoing values into /proc/sysrq-trigger seems to be a popular way to > > get information out of the kernel. However, dumping information about > > thousands of processes, or hundreds of CPUs to serial console can > > result in IRQs being blocked for minutes, resulting in various kinds > > of cascade failures. > > > > The most common failure is due to interrupts being blocked for a very > > long time. This can lead to things like failed IO requests, and other > > things the system cannot easily recover from. > > I bet nobody wants that console output anyway. You do the sysrq then > run dmesg or look in /var/log/messages to see what happened. People > who are experiencing problems such as this should run `dmesg -n 1' > before writing to sysrq-trigger.
I don't agree. I have used sysrq-t multiple times in situations where userspace was already dead, but sysrq was still able to provide valuable information about the state of the kernel. -- Jiri Kosina SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
