| Message ID | 20240111162419.12406-1-pmladek@suse.com |
|---|---|
| State | New |
| Headers | show |
| Series | scsi: core: Safe warning about bad dev info string | expand |
Petr Mladek writes: >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. Acked-by: Chris Down <chris@chrisdown.name> While I agree with the other thread that in reality this is ok, it's worth reducing the addition to LKP noise for now and worrying about that later. Thanks! > >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, >-- >2.43.0 >
On Thu, 11 Jan 2024 17:24:19 +0100, 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: > > [...] Applied to 6.9/scsi-queue, thanks! [1/1] scsi: core: Safe warning about bad dev info string https://git.kernel.org/mkp/scsi/c/796cae1a79b1
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,
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(-)