Merge branch 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...

Pull SMP fixes from Thomas Gleixner:
 "Two small changes for the cpu hotplug code:

   - Prevent out of bounds access which actually might crash the machine
     caused by a missing bounds check in the fail injection code

   - Warn about unsupported migitation mode command line arguments to
     make people aware that they typoed the paramater. Not necessarily a
     fix but quite some people tripped over that"

* 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  cpu/hotplug: Fix out-of-bounds read when setting fail state
  cpu/speculation: Warn on unsupported mitigations= parameter

diff --git a/kernel/cpu.c b/kernel/cpu.c
index 077fde6..ef1c565 100644 (file)
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -1964,6 +1964,9 @@ static ssize_t write_cpuhp_fail(struct device *dev,
        if (ret)
                return ret;
 
+       if (fail < CPUHP_OFFLINE || fail > CPUHP_ONLINE)
+               return -EINVAL;
+
        /*
         * Cannot fail STARTING/DYING callbacks.
         */
@@ -2339,6 +2342,9 @@ static int __init mitigations_parse_cmdline(char *arg)
                cpu_mitigations = CPU_MITIGATIONS_AUTO;
        else if (!strcmp(arg, "auto,nosmt"))
                cpu_mitigations = CPU_MITIGATIONS_AUTO_NOSMT;
+       else
+               pr_crit("Unsupported mitigations=%s, system may still be vulnerable\n",
+                       arg);
 
        return 0;
 }