[bug report] tests/liveupdate: add in-kernel liveupdate test

[Dan Carpenter <dan.carpenter@linaro.org>]

[ Smatch checking is paused while we raise funding. #SadFace
  https://lore.kernel.org/all/aTaiGSbWZ9DJaGo7@stanley.mountain/ -dan ]

Hello Pasha Tatashin,

Commit f653ff7af969 ("tests/liveupdate: add in-kernel liveupdate
test") from Dec 18, 2025 (linux-next), leads to the following Smatch
static checker warning:

	lib/tests/liveupdate.c:130 liveupdate_test_register()
	warn: passing zero to 'ERR_PTR'

lib/tests/liveupdate.c
    112 void liveupdate_test_register(struct liveupdate_file_handler *fh)
    113 {
    114         int err, i;
    115 
    116         liveupdate_test_init();
    117 
    118         for (i = 0; i < TEST_NFLBS; i++) {
    119                 struct liveupdate_flb *flb = &test_flbs[i];
    120 
    121                 err = liveupdate_register_flb(fh, flb);
    122                 if (err) {
    123                         pr_err("Failed to register %s %pe\n",
    124                                flb->compatible, ERR_PTR(err));
    125                 }
    126         }
    127 
    128         err = liveupdate_register_flb(fh, &test_flbs[0]);
    129         if (!err || err != -EEXIST) {
                         ^^
|| vs && bug.  This error messages will always be printed.

--> 130                 pr_err("Failed: %s should be already registered, but got err: %pe\n",
    131                        test_flbs[0].compatible, ERR_PTR(err));
    132         }
    133 
    134         pr_info("Registered %d FLBs with file handler: [%s]\n",
    135                 TEST_NFLBS, fh->compatible);
    136 }

regards,
dan carpenter