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Dan Carpenter <dan.carpenter@oracle.com> wrote: > > url: https://github.com/0day-ci/linux/commits/legion-kernel-org/Count-rlimits-in-each-user-namespace/20210427-162857 > base: https://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest.git next > config: arc-randconfig-m031-20210426 (attached as .config) > compiler: arceb-elf-gcc (GCC) 9.3.0 > > If you fix the issue, kindly add following tag as appropriate > Reported-by: kernel test robot <lkp@intel.com> > Reported-by: Dan Carpenter <dan.carpenter@oracle.com> > > smatch warnings: > kernel/ucount.c:270 dec_rlimit_ucounts() error: uninitialized symbol 'new'. > > vim +/new +270 kernel/ucount.c > > 176ec2b092cc22 Alexey Gladkov 2021-04-22 260 bool dec_rlimit_ucounts(struct ucounts *ucounts, enum ucount_type type, long v) > 176ec2b092cc22 Alexey Gladkov 2021-04-22 261 { > 176ec2b092cc22 Alexey Gladkov 2021-04-22 262 struct ucounts *iter; > 176ec2b092cc22 Alexey Gladkov 2021-04-22 263 long new; > ^^^^^^^^ > > 176ec2b092cc22 Alexey Gladkov 2021-04-22 264 for (iter = ucounts; iter; iter = iter->ns->ucounts) { > 176ec2b092cc22 Alexey Gladkov 2021-04-22 265 long dec = atomic_long_add_return(-v, &iter->ucount[type]); > 176ec2b092cc22 Alexey Gladkov 2021-04-22 266 WARN_ON_ONCE(dec < 0); > 176ec2b092cc22 Alexey Gladkov 2021-04-22 267 if (iter == ucounts) > 176ec2b092cc22 Alexey Gladkov 2021-04-22 268 new = dec; > 176ec2b092cc22 Alexey Gladkov 2021-04-22 269 } > 176ec2b092cc22 Alexey Gladkov 2021-04-22 @270 return (new == 0); > ^^^^^^^^ > I don't know if this is a bug or not, but I can definitely tell why the > static checker complains about it. > > 176ec2b092cc22 Alexey Gladkov 2021-04-22 271 } In the only two cases that care about the return value of dec_rlimit_ucounts the code first tests to see that ucounts is not NULL. In those cases it is guaranteed at least one iteration of the loop will execute guaranteeing the variable new will be initialized. Initialize new to -1 so that the return value is well defined even when the loop does not execute and the static checker is silenced. Link: https://lkml.kernel.org/r/m1tunny77w.fsf@fess.ebiederm.org Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> |
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Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.