On Wed, May 13, 2020 at 10:35:16AM -0400, Pavel Tatashin wrote:

quoted

quoted

  + reason: panic, oops, emergency, shutdown    (ordered by severity)
  + handling: restart, halt, poweroff

Or we might just replace KMSG_DUMP_RESTART, KMSG_DUMP_HALT,
KMSG_DUMP_POWEROFF with a single KMSG_DUMP_SHUTDOWN.

Then the max reason variable would make sense.

That would work for me, yeah. Pavel, is that enough granularity for you?

Yes, I like the second approach: where we combine all shutdown type
events into a single type.
max_reason will have 4 levels:

   KMSG_DUMP_PANIC,
   KMSG_DUMP_OOPS,
   KMSG_DUMP_EMERG,
   KMSG_DUMP_SHUTDOWN,

If needed it is possible to determine from dmesg logs what kind of
shutdown was taken, because there is a message logged right before
every kmsg_dump() for these events:

249   if (!cmd)
250   pr_emerg("Restarting system\n");
251   else
252   pr_emerg("Restarting system with command '%s'\n", cmd);
253   kmsg_dump(KMSG_DUMP_RESTART);

276   pr_emerg("System halted\n");
277   kmsg_dump(KMSG_DUMP_HALT);

294   pr_emerg("Power down\n");
295   kmsg_dump(KMSG_DUMP_POWEROFF);

Kees, I will submit a new series with these changes soon.

Great; thanks!

-Kees

-- 
Kees Cook