The earliest mention I find of this on lkml is v4. Was there earlier discussion of this elsewhere? (Just so I have a clue as to the full context and don't repeat previous discussion.) The mention of names in the change logs tells me I should be able to find the discussion somewhere.
On 9/28/2014 7:40 PM, Andy Lutomirski wrote: > 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 makes a failure to run the specified init= process be fatal. > > As a temporary measure, users can set CONFIG_INIT_FALLBACK=y to > preserve the old behavior. If no one speaks up, we can remove that > option entirely after a release or two. I'm speaking up already, no need to wait two releases. I like the current behavior where I can fall back into a shell without recompiling the kernel and/or changing the boot command line to debug an init failure. I would suggest that the current behavior remain the default and the choice to make a failure of the specified init= process fatal should be an explicit choice. Instead of using a config option, would adding another kernel command line option, such as 'init_fail_is_fatal', work for your needs? I have a feeling this has already been proposed, as the 'strictinit' option mentioned in the changes from v3 below might be the same concept? Thanks, Frank > > Signed-off-by: Andy Lutomirski <[email protected]> > --- > > Changes from v4: > - Update the panic message (sorry for the noise) > > Changes from v3: > - Get rid of the strictinit option. Now the new behavior is the default > unless CONFIG_INIT_FALLBACK=y (Rob Landley) > > Changes from v2: > - Improve docs further, to leave the door open to giving strictinit > some sensible semantics if init= is not set. > - Improve error output in the failure case (Shuah Khan). > > Changes from v1: > - Add missing "if" to the docs (Randy Dunlap) > > init/Kconfig | 11 +++++++++++ > init/main.c | 7 ++++++- > 2 files changed, 17 insertions(+), 1 deletion(-) > > diff --git a/init/Kconfig b/init/Kconfig > index e84c6423a2e5..063029a1556f 100644 > --- a/init/Kconfig > +++ b/init/Kconfig > @@ -1299,6 +1299,17 @@ source "usr/Kconfig" > > endif > > +config INIT_FALLBACK > + bool "Fall back to defaults if init= parameter is bad" > + help > + If enabled, the kernel will try the default init binaries if an > + explicit request from the init= parameter fails. > + > + This is a temporary measure to allow broken configurations > + to continue to boot. > + > + If unsure, say N. > + > config CC_OPTIMIZE_FOR_SIZE > bool "Optimize for size" > help > diff --git a/init/main.c b/init/main.c > index bb1aed928f21..2bd6105e5dc5 100644 > --- a/init/main.c > +++ b/init/main.c > @@ -960,8 +960,13 @@ 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") || > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
