On Mon, May 11, 2020 at 06:21:13PM +0200, Greg Kroah-Hartman wrote: > On Mon, May 11, 2020 at 03:59:18PM +0200, Andrzej Pietrasiewicz wrote: > > Some userland might want to execute e.g. 'w' (show blocked tasks), followed > > by 's' (sync), followed by 1000 ms delay and then followed by 'c' (crash) > > upon a single magic SysRq. Or one might want to execute the famous "Raising > > Elephants Is So Utterly Boring" action. This patch adds a configurable > > handler, triggered with 'C', for this exact purpose. The user specifies the > > composition of the compound action using syntax similar to getopt, where > > each letter corresponds to an individual action and a colon followed by a > > number corresponds to a delay of that many milliseconds, e.g.: > > > > ws:1000c > > > > or > > > > r:100eis:1000ub > > Cute, but why? Who needs/wants this type of thing? On Chrome OS the first time user presses SysRq-X it will try to kill chrome (and that will cause crash to get uploaded if user consented). The 2nd time within 5 seconds the same combo is pressed, it will dump blocked tasks in syslog and try to sync and then panic. On panic the device will reboot, logs will be scraped from pstore, and uploaded for analysis. Thanks. -- Dmitry
