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| author |   Andy Lutomirski <luto@amacapital.net> | 2014-12-10 15:52:19 -0800 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2014-12-10 17:41:12 -0800 |
| commit | 6ef4536e2f19c4dba3637413d73ea00b19764bc0 (patch) | |
| tree | e286e65b4ba1ce1089a7dc87cf642cfb6fdbbe6b /init | |
| parent | fs/binfmt_elf.c: fix internal inconsistency relating to vma dump size (diff) | |
| download | linux-dev-6ef4536e2f19c4dba3637413d73ea00b19764bc0.tar.xz linux-dev-6ef4536e2f19c4dba3637413d73ea00b19764bc0.zip | |
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>
Diffstat (limited to 'init')
| -rw-r--r-- | init/Kconfig | 16 | ||||
| -rw-r--r-- | init/main.c | 7 |
2 files changed, 22 insertions, 1 deletions
diff --git a/init/Kconfig b/init/Kconfig index 7e9fbd48e2ab..9afb971497f4 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1280,6 +1280,22 @@ source "usr/Kconfig" endif +config INIT_FALLBACK + bool "Fall back to defaults if init= parameter is bad" + default y + help + If enabled, the kernel will try the default init binaries if an + explicit request from the init= parameter fails. + + This can have unexpected effects. For example, booting + with init=/sbin/kiosk_app will run /sbin/init or even /bin/sh + if /sbin/kiosk_app cannot be executed. + + The default value of Y is consistent with historical behavior. + Selecting N is likely to be more appropriate for most uses, + especially on kiosks and on kernels that are intended to be + run under the control of a script. + config CC_OPTIMIZE_FOR_SIZE bool "Optimize for size" help diff --git a/init/main.c b/init/main.c index d2e4ead4891f..ca380ec685de 100644 --- a/init/main.c +++ b/init/main.c @@ -952,8 +952,13 @@ static int __ref kernel_init(void *unused) 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") || |