From f1a5b96219e3483ab519bed9bb04cc8fadf74816 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Mon, 13 Jun 2011 10:30:00 -0400 Subject: [PATCH] ktest: Add detection of triple faults When a triple fault happens in a test, no call trace nor panic is displayed. Instead, the system reboots to the good kernel. Since the good kernel may display a boot prompt that matches the success string, ktest may think that the test succeeded, when it did not. Detecting triple faults is tricky because it is hard to generalize what a reboot looks like. The best that we can come up with for now is to examine the Linux banner. If we detect that the Linux banner matches the test we want to test, then look to see if we hit another Linux banner with a different kernel is booted. This can be assumed to be a triple fault. We can't just check for two Linux banners because things like early printk may cause the Linux banner to be displayed twice. Checking for different kernel versions should be the safe bet. If this for some reason detects a false triple boot. A new ktest config option is also created: DETECT_TRIPLE_FAULT This can be set to 0 to disable this checking. Signed-off-by: Steven Rostedt --- Reading git-format-patch failed