I ran the command:

sudo grep -r -i RETP  /sys/*

On two systems: Oracle Linux 7.5 server (256 GB RAM, 2 Intel® Xeon® Gold 6142 Processor) and on my desktop PC with Ubuntu 18.04 (16 GB RAM, Core i5-6400). In both scenarios, Linux OS hung!

Could you please explain why?

  • P.S> on virtual machines (VirtualBox) all fine, the problem occures only with Physical machines. – Vsevolod Gromov Sep 23 '18 at 14:38
  • Does the whose machine hand, or just the terminal, that ran the command? – ctrl-alt-delor Sep 23 '18 at 14:42
  • servers fully hung, not a treminal. – Vsevolod Gromov Sep 23 '18 at 14:58
  • Parts of /sys/ tap into hardware and firmware. It would be dependent on your specific system model/brand anyway. Use known places. Eg, if looking for retpoline vulnerability, replace with grep -r -i RETP /sys/devices/system/cpu/vulnerabilities – A.B Sep 23 '18 at 15:27
  • 1
    Try finding what file exactly cause it to hang with find /sys -type f | xargs sh -c 'for a; do echo $a; cat $a >/dev/null; done' sh; the last one printed may be the culprit. – mosvy Sep 23 '18 at 15:55

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