On 1/11/24 08:24, Petr Mladek wrote:
Both "model" and "strflags" are passed to "%s" even when one or both are NULL. It is safe because vsprintf() would detect the NULL pointer and print "(null)". But it is a kernel-specific feature and compiler warns about it: <warning> In file included from include/linux/kernel.h:19, from arch/x86/include/asm/percpu.h:27, from arch/x86/include/asm/current.h:6, from include/linux/sched.h:12, from include/linux/blkdev.h:5, from drivers/scsi/scsi_devinfo.c:3: drivers/scsi/scsi_devinfo.c: In function 'scsi_dev_info_list_add_str':include/linux/printk.h:434:44: warning: '%s' directive argument is null [-Wformat-overflow=]434 | #define printk(fmt, ...) printk_index_wrap(_printk, fmt, ##__VA_ARGS__) | ^ include/linux/printk.h:430:3: note: in definition of macro 'printk_index_wrap' 430 | _p_func(_fmt, ##__VA_ARGS__); \ | ^~~~~~~ drivers/scsi/scsi_devinfo.c:551:4: note: in expansion of macro 'printk' 551 | printk(KERN_ERR "%s: bad dev info string '%s' '%s'" | ^~~~~~ drivers/scsi/scsi_devinfo.c:552:14: note: format string is defined here 552 | " '%s'\n", __func__, vendor, model, | ^~ </warning> Do not rely on the kernel specific behavior and print the message a safe way. Reported-by: kernel test robot <lkp@xxxxxxxxx> Closes: https://lore.kernel.org/oe-kbuild-all/202401112002.AOjwMNM0-lkp@xxxxxxxxx/ Signed-off-by: Petr Mladek <pmladek@xxxxxxxx> --- Note: The patch is only compile tested. drivers/scsi/scsi_devinfo.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/scsi/scsi_devinfo.c b/drivers/scsi/scsi_devinfo.c index 3fcaf10a9dfe..ba7237e83863 100644 --- a/drivers/scsi/scsi_devinfo.c +++ b/drivers/scsi/scsi_devinfo.c @@ -551,9 +551,9 @@ static int scsi_dev_info_list_add_str(char *dev_list) if (model) strflags = strsep(&next, next_check); if (!model || !strflags) { - printk(KERN_ERR "%s: bad dev info string '%s' '%s'" - " '%s'\n", __func__, vendor, model, - strflags); + pr_err("%s: bad dev info string '%s' '%s' '%s'\n", + __func__, vendor, model ? model : "", + strflags ? strflags : ""); res = -EINVAL; } else res = scsi_dev_info_list_add(0 /* compatible */, vendor,
Expressions like "model ? model : """ can be shortened into "model ? : """. Anyway: Reviewed-by: Bart Van Assche <bvanassche@xxxxxxx>
