Re: drivers/gpu/drm/udl/udl_main.c:259 udl_get_urb_locked() warn: can 'unode' even be NULL?

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

On Tue, May 02, 2023 at 01:38:11PM +0200, Thomas Zimmermann wrote:
> Hi
> 
> Am 02.05.23 um 13:19 schrieb Dan Carpenter:
> > tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> > head:   2caeeb9d4a1bccd923b7918427f9e9ef7151ddd8
> > commit: c5c354a3a4728045e1342166394c615d75d45377 drm/udl: Fix inconsistent urbs.count value during udl_free_urb_list()
> > config: parisc-randconfig-m031-20230421 (https://download.01.org/0day-ci/archive/20230423/202304230801.ncoG1XDr-lkp@intel.com/config)
> > compiler: hppa-linux-gcc (GCC) 12.1.0
> > 
> > If you fix the issue, kindly add following tag where applicable
> > | Reported-by: kernel test robot <lkp@intel.com>
> > | Reported-by: Dan Carpenter <error27@gmail.com>
> > | Link: https://lore.kernel.org/r/202304230801.ncoG1XDr-lkp@intel.com/
> > 
> > smatch warnings:
> > drivers/gpu/drm/udl/udl_main.c:259 udl_get_urb_locked() warn: can 'unode' even be NULL?
> 
> It can't. Send a fix, if you like. OTOH it's not much of a problem either.
> 

Sure, I sent a patch.  This one is harmless, but we recently had a few
bugs that should have generated bogus NULL check warnings.

CVE-2023-1073: b12fece4c648 ("HID: check empty report_list in hid_validate_values()")
CVE-2023-1075: ffe2a2256244 ("net/tls: tls_is_tx_ready() checked list_entry")
CVE-2023-1077: 7c4a5b89a0b5 ("sched/rt: pick_next_rt_entity(): check list_entry")
CVE-2023-1078: f753a68980cf ("rds: rds_rm_zerocopy_callback() use list_first_entry()")

Although CVE-2023-1073 and CVE-2023-1077 are hard to warn about without
generating too many false positives.

regards,
dan carpenter