init: allow CONFIG_INIT_FALLBACK=n to disable defaults if init= fails
If a user puts init=/whatever on the command line and /whatever can't be
run, then the kernel will try a few default options before giving up. If
init=/whatever came from a bootloader prompt, then this is unexpected but
probably harmless. On the other hand, if it comes from a script (e.g. a
tool like virtme or perhaps a future kselftest script), then the fallbacks
are likely to exist, but they'll do the wrong thing. For example, they
might unexpectedly invoke systemd.
This adds a config option CONFIG_INIT_FALLBACK. If unset, then a failure
to run the specified init= process be fatal.
The tentative plan is to remove CONFIG_INIT_FALLBACK for 3.20.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Cc: Rob Landley <rob@landley.net>
Cc: Chuck Ebbert <cebbert.lkml@gmail.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Shuah Khan <shuah.kh@samsung.com>
Cc: Frank Rowand <frowand.list@gmail.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/init/main.c b/init/main.c
index d2e4ead..ca380ec 100644
--- a/init/main.c
+++ b/init/main.c
@@ -952,8 +952,13 @@
ret = run_init_process(execute_command);
if (!ret)
return 0;
+#ifndef CONFIG_INIT_FALLBACK
+ panic("Requested init %s failed (error %d).",
+ execute_command, ret);
+#else
pr_err("Failed to execute %s (error %d). Attempting defaults...\n",
- execute_command, ret);
+ execute_command, ret);
+#endif
}
if (!try_to_run_init_process("/sbin/init") ||
!try_to_run_init_process("/etc/init") ||