4.4-stable review patch. If anyone has any objections, please let me know.
------------------ From: Peter Zijlstra <[email protected]> commit a5f81290ce475489fa2551c01a07470c1a4c932e upstream. > arch/x86/events/intel/cstate.c:307 cstate_pmu_event_init() warn: potential > spectre issue 'pkg_msr' (local cap) Userspace controls @attr, sanitize cfg (attr->config) 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: Alexander Shishkin <[email protected]> Cc: Arnaldo Carvalho de Melo <[email protected]> Cc: Jiri Olsa <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Stephane Eranian <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Vince Weaver <[email protected]> Signed-off-by: Ingo Molnar <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- arch/x86/kernel/cpu/perf_event_intel_cstate.c | 2 ++ 1 file changed, 2 insertions(+) --- a/arch/x86/kernel/cpu/perf_event_intel_cstate.c +++ b/arch/x86/kernel/cpu/perf_event_intel_cstate.c @@ -88,6 +88,7 @@ #include <linux/module.h> #include <linux/slab.h> #include <linux/perf_event.h> +#include <linux/nospec.h> #include <asm/cpu_device_id.h> #include "perf_event.h" @@ -409,6 +410,7 @@ static int cstate_pmu_event_init(struct } else if (event->pmu == &cstate_pkg_pmu) { if (cfg >= PERF_CSTATE_PKG_EVENT_MAX) return -EINVAL; + cfg = array_index_nospec((unsigned long)cfg, PERF_CSTATE_PKG_EVENT_MAX); if (!pkg_msr[cfg].attr) return -EINVAL; event->hw.event_base = pkg_msr[cfg].msr;
