On Tue, Apr 10, 2018 at 04:50:51PM -0400, Joe Lawrence wrote:
> On 04/10/2018 04:00 PM, Josh Poimboeuf wrote:
> > On Tue, Apr 10, 2018 at 11:15:54AM -0400, Joe Lawrence wrote:
> >> +static void test_klp_shadow_vars_exit(void)
> >> +{
> >> +}
> >> +
> >> +module_init(test_klp_shadow_vars_init);
> >> +module_init(test_klp_shadow_vars_exit);
> >
> > For this last line, s/module_init/module_exit/, though I think the exit
> > function can just be removed altogether?
>
> D'oh workspace / git user error, I posted an older version :(
>
> But the exit function seems to be required if an init function is
> provided. Here I omitted the exit function:
>
> % modprobe test_klp_shadow_vars
> % lsmod | grep test_klp_shadow_vars
> test_klp_shadow_vars 16384 0
> % rmmod test_klp_shadow_vars
> rmmod: ERROR: could not remove 'test_klp_shadow_vars': Device or
> resource busy
> rmmod: ERROR: could not remove module test_klp_shadow_vars: Device or
> resource busy
>
> and from kernel/module.c
>
> SYSCALL_DEFINE2(delete_module, const char __user *, name_user,
> unsigned int, flags)
> ...
> /* If it has an init func, it must have an exit func to unload*/
> if (mod->init && !mod->exit) {
> forced = try_force_unload(flags);
> if (!forced) {
> /* This module can't be removed */
> ret = -EBUSY;
> goto out;
> }
> }
> ...
Hm, ok, though that seems like a weird limitation...
> I missed Petr's commit msg note "that the constructor is called under
> klp_shadow_lock." I'll convert the test to use GFP_ATOMIC for this
> allocation.
>
> I'll also add CONFIG_PM_SLEEP_DEBUG=y to my test VM kernel .config. Any
> other debug option suggestions?
I think CONFIG_LOCKDEP is always a good idea. Otherwise, I dunno...
Here's my .config:
https://paste.fedoraproject.org/paste/cnM-J18uVWJrxz2DAdSchg
--
Josh
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