Messages in this thread | | | From | Suren Baghdasaryan <> | Date | Fri, 20 May 2022 10:09:20 -0700 | Subject | Re: [PATCH] sched/psi: Bounds-check state iterator against NR_PSI_STATES |
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On Fri, May 20, 2022 at 9:58 AM Kees Cook <keescook@chromium.org> wrote: > > GCC 12 cannot tell that "t" will be bounded by NR_PSI_STATES, which could > lead to walking off the end of the tasks array, which is NR_PSI_STATES in > size. Explicitly bounds-check "t" as part of the loop. > > In file included from ../kernel/sched/build_utility.c:97: > ../kernel/sched/psi.c: In function 'psi_group_change': > ../kernel/sched/psi.c:730:38: warning: array subscript 32 is above array bounds of 'unsigned int[5]' [-Warray-bounds] > 730 | groupc->tasks[t]++; > | ~~~~~~~~~~~~~^~~ > In file included from ../include/linux/psi.h:6, > from ../kernel/sched/build_utility.c:36: > ../include/linux/psi_types.h:84:22: note: while referencing 'tasks' > 84 | unsigned int tasks[NR_PSI_TASK_COUNTS]; > | ^~~~~ > ../kernel/sched/psi.c:730:38: warning: array subscript 32 is above array bounds of 'unsigned int[5]' [-Warray-bounds] > 730 | groupc->tasks[t]++; > | ~~~~~~~~~~~~~^~~ > ../include/linux/psi_types.h:84:22: note: while referencing 'tasks' > 84 | unsigned int tasks[NR_PSI_TASK_COUNTS]; > | ^~~~~ > > Cc: Johannes Weiner <hannes@cmpxchg.org> > Cc: Suren Baghdasaryan <surenb@google.com> > Cc: Ingo Molnar <mingo@redhat.com> > Cc: Peter Zijlstra <peterz@infradead.org> > Cc: Juri Lelli <juri.lelli@redhat.com> > Cc: Vincent Guittot <vincent.guittot@linaro.org> > Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> > Cc: Steven Rostedt <rostedt@goodmis.org> > Cc: Ben Segall <bsegall@google.com> > Cc: Mel Gorman <mgorman@suse.de> > Cc: Daniel Bristot de Oliveira <bristot@redhat.com> > Cc: Valentin Schneider <vschneid@redhat.com> > Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
> --- > kernel/sched/psi.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c > index a337f3e35997..827f16a79936 100644 > --- a/kernel/sched/psi.c > +++ b/kernel/sched/psi.c > @@ -725,7 +725,7 @@ static void psi_group_change(struct psi_group *group, int cpu, > } > } > > - for (t = 0; set; set &= ~(1 << t), t++) > + for (t = 0; set && t < ARRAY_SIZE(groupc->tasks); set &= ~(1 << t), t++) > if (set & (1 << t)) > groupc->tasks[t]++; > > -- > 2.32.0 >
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