Messages in this thread | | | Date | Thu, 11 Jan 2024 09:55:54 -0800 | Subject | Re: [PATCH] scsi: core: Safe warning about bad dev info string | From | Bart Van Assche <> |
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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@intel.com> > Closes: https://lore.kernel.org/oe-kbuild-all/202401112002.AOjwMNM0-lkp@intel.com/ > Signed-off-by: Petr Mladek <pmladek@suse.com> > --- > 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@acm.org>
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