On Fri, Sep 26, 2014 at 12:23 PM, Chuck Ebbert <[email protected]> wrote: > On Fri, 26 Sep 2014 12:13:57 -0700 > Andy Lutomirski <[email protected]> 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 probably makes sense. 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 new option called strictinit. If init= and strictinit >> are both set, and the init= binary is not executable, then the >> kernel will panic immediately. If strictinit is set but init= is >> not set, then strictinit will have no effect, because the only real >> alternative would be to panic regardless of the contents of the root >> fs. >> >> Signed-off-by: Andy Lutomirski <[email protected]> >> --- >> Documentation/kernel-parameters.txt | 8 ++++++++ >> init/main.c | 16 ++++++++++++++-- >> 2 files changed, 22 insertions(+), 2 deletions(-) >> >> diff --git a/Documentation/kernel-parameters.txt >> b/Documentation/kernel-parameters.txt >> index 10d51c2f10d7..1576273edce6 100644 >> --- a/Documentation/kernel-parameters.txt >> +++ b/Documentation/kernel-parameters.txt >> @@ -3236,6 +3236,14 @@ bytes respectively. Such letter suffixes can also be >> entirely omitted. >> stifb= [HW] >> Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]] >> >> + strictinit [KNL,BOOT] >> + Normally, if the kernel can't find the init binary >> + specified by rdinit= and/or init=, then it will >> + try several fallbacks. If strictinit is set >> + and the value specified by init= does not work, >> + then the kernel will panic instead. >> + This option makes no sense if init= is not specified. >> + >> sunrpc.min_resvport= >> sunrpc.max_resvport= >> [NFS,SUNRPC] >> diff --git a/init/main.c b/init/main.c >> index bb1aed928f21..2ae0f2776155 100644 >> --- a/init/main.c >> +++ b/init/main.c >> @@ -131,6 +131,7 @@ static char *initcall_command_line; >> >> static char *execute_command; >> static char *ramdisk_execute_command; >> +static bool strictinit; >> >> /* >> * Used to generate warnings if static_key manipulation functions are used >> @@ -347,6 +348,13 @@ static int __init rdinit_setup(char *str) >> } >> __setup("rdinit=", rdinit_setup); >> >> +static int __init strictinit_setup(char *str) >> +{ >> + strictinit = true; >> + return 1; >> +} >> +__setup("strictinit", strictinit_setup); >> + >> #ifndef CONFIG_SMP >> static const unsigned int setup_max_cpus = NR_CPUS; >> #ifdef CONFIG_X86_LOCAL_APIC >> @@ -960,8 +968,12 @@ static int __ref kernel_init(void *unused) >> ret = run_init_process(execute_command); >> if (!ret) >> return 0; >> - pr_err("Failed to execute %s (error %d). Attempting >> defaults...\n", >> - execute_command, ret); >> + if (strictinit) >> + panic("Requested init %s failed (error %d) and >> strictinit was set.", >> + execute_command, ret); >> + else >> + pr_err("Failed to execute %s (error %d). Attempting >> defaults...\n", >> + execute_command, ret); >> } >> if (!try_to_run_init_process("/sbin/init") || >> !try_to_run_init_process("/etc/init") || > > Can't you just make it use "init=foo,strict" instead?
I don't think so. Old kernels will wonder why "foo,strict" doesn't exist. -- Andy Lutomirski AMA Capital Management, LLC -- 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/
