3.16.60-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Peter Zijlstra <peterz@xxxxxxxxxxxxx> commit 354d7793070611b4df5a79fbb0f12752d0ed0cc5 upstream. > kernel/sched/autogroup.c:230 proc_sched_autogroup_set_nice() warn: potential spectre issue 'sched_prio_to_weight' Userspace controls @nice, sanitize the array index. Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> [bwh: Backported to 3.16: adjust filename, context] Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx> --- kernel/sched/auto_group.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) --- a/kernel/sched/auto_group.c +++ b/kernel/sched/auto_group.c @@ -8,6 +8,7 @@ #include <linux/utsname.h> #include <linux/security.h> #include <linux/export.h> +#include <linux/nospec.h> unsigned int __read_mostly sysctl_sched_autogroup_enabled = 1; static struct autogroup autogroup_default; @@ -198,7 +199,7 @@ int proc_sched_autogroup_set_nice(struct static unsigned long next = INITIAL_JIFFIES; struct autogroup *ag; unsigned long shares; - int err; + int err, idx; if (nice < MIN_NICE || nice > MAX_NICE) return -EINVAL; @@ -216,7 +217,9 @@ int proc_sched_autogroup_set_nice(struct next = HZ / 10 + jiffies; ag = autogroup_task_get(p); - shares = scale_load(prio_to_weight[nice + 20]); + + idx = array_index_nospec(nice + 20, 40); + shares = scale_load(prio_to_weight[idx]); down_write(&ag->lock); err = sched_group_set_shares(ag->tg, shares);
