Messages in this thread Patch in this message | | | From | Kees Cook <> | Subject | [PATCH] sched/psi: Bounds-check state iterator against NR_PSI_STATES | Date | Fri, 20 May 2022 09:58:26 -0700 |
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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> --- 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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