kthread_create_on_cpu() always requires format string to contain one '%u' at the end, as it automatically adds the CPU ID when passing it to kthread_create_on_node(). The former isn't marked as __printf() as it's not printf-like itself, which effectively hides this from the compiler. If you convert this function to printf-like, you'll see the following: In file included from drivers/firmware/psci/psci_checker.c:15: drivers/firmware/psci/psci_checker.c: In function 'suspend_tests': drivers/firmware/psci/psci_checker.c:401:48: warning: too many arguments for format [-Wformat-extra-args] 401 | "psci_suspend_test"); | ^~~~~~~~~~~~~~~~~~~ drivers/firmware/psci/psci_checker.c:400:32: warning: data argument not used by format string [-Wformat-extra-args] 400 | (void *)(long)cpu, cpu, | ^ 401 | "psci_suspend_test"); | ~~~~~~~~~~~~~~~~~~~ Add the missing format literal to fix this. Now the corresponding kthread will be named as "psci_suspend_test-<cpuid>", as it's meant by kthread_create_on_cpu(). Reported-by: kernel test robot <lkp@xxxxxxxxx> Closes: https://lore.kernel.org/oe-kbuild-all/202408141012.KhvKaxoh-lkp@xxxxxxxxx Closes: https://lore.kernel.org/oe-kbuild-all/202408141243.eQiEOQQe-lkp@xxxxxxxxx Fixes: ea8b1c4a6019 ("drivers: psci: PSCI checker module") Cc: stable@xxxxxxxxxxxxxxx # 4.10+ Signed-off-by: Alexander Lobakin <aleksander.lobakin@xxxxxxxxx> --- drivers/firmware/psci/psci_checker.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/firmware/psci/psci_checker.c b/drivers/firmware/psci/psci_checker.c index 116eb465cdb4..ecc511c745ce 100644 --- a/drivers/firmware/psci/psci_checker.c +++ b/drivers/firmware/psci/psci_checker.c @@ -398,7 +398,7 @@ static int suspend_tests(void) thread = kthread_create_on_cpu(suspend_test_thread, (void *)(long)cpu, cpu, - "psci_suspend_test"); + "psci_suspend_test-%u"); if (IS_ERR(thread)) pr_err("Failed to create kthread on CPU %d\n", cpu); else -- 2.46.2