4.16-stable review patch. If anyone has any objections, please let me know.
------------------ From: Peter Zijlstra <[email protected]> commit 7281c8dec8a87685cb54d503d8cceef5a0fc2fdd upstream. > kernel/sched/core.c:6921 cpu_weight_nice_write_s64() warn: potential spectre > issue 'sched_prio_to_weight' Userspace controls @nice, so sanitize the value before using it to index an array. Reported-by: Dan Carpenter <[email protected]> Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Cc: <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Mike Galbraith <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: [email protected] Signed-off-by: Ingo Molnar <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- kernel/sched/core.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -23,6 +23,7 @@ #include <linux/mmu_context.h> #include <linux/module.h> #include <linux/nmi.h> +#include <linux/nospec.h> #include <linux/prefetch.h> #include <linux/profile.h> #include <linux/security.h> @@ -6873,11 +6874,15 @@ static int cpu_weight_nice_write_s64(str struct cftype *cft, s64 nice) { unsigned long weight; + int idx; if (nice < MIN_NICE || nice > MAX_NICE) return -ERANGE; - weight = sched_prio_to_weight[NICE_TO_PRIO(nice) - MAX_RT_PRIO]; + idx = NICE_TO_PRIO(nice) - MAX_RT_PRIO; + idx = array_index_nospec(idx, 40); + weight = sched_prio_to_weight[idx]; + return sched_group_set_shares(css_tg(css), scale_load(weight)); } #endif
