xfs: fix reading of wrapped log data

[karo-tx-linux.git] / kernel / sys.c

diff --git a/kernel/sys.c b/kernel/sys.c
index 2d39a84cd8575e6295f666421cee01b41652b3b1..909148a08ec5bbe140f193bab9ec17590c528b1c 100644 (file)
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -368,6 +368,7 @@ EXPORT_SYMBOL(unregister_reboot_notifier);
 void kernel_restart(char *cmd)
 {
        kernel_restart_prepare(cmd);
+       disable_nonboot_cpus();
        if (!cmd)
                printk(KERN_EMERG "Restarting system.\n");
        else
@@ -1264,15 +1265,16 @@ DECLARE_RWSEM(uts_sem);
  * Work around broken programs that cannot handle "Linux 3.0".
  * Instead we map 3.x to 2.6.40+x, so e.g. 3.0 would be 2.6.40
  */
-static int override_release(char __user *release, int len)
+static int override_release(char __user *release, size_t len)
 {
        int ret = 0;
-       char buf[65];
 
        if (current->personality & UNAME26) {
-               char *rest = UTS_RELEASE;
+               const char *rest = UTS_RELEASE;
+               char buf[65] = { 0 };
                int ndots = 0;
                unsigned v;
+               size_t copy;
 
                while (*rest) {
                        if (*rest == '.' && ++ndots >= 3)
@@ -1282,8 +1284,9 @@ static int override_release(char __user *release, int len)
                        rest++;
                }
                v = ((LINUX_VERSION_CODE >> 8) & 0xff) + 40;
-               snprintf(buf, len, "2.6.%u%s", v, rest);
-               ret = copy_to_user(release, buf, len);
+               copy = clamp_t(size_t, len, 1, sizeof(buf));
+               copy = scnprintf(buf, copy, "2.6.%u%s", v, rest);
+               ret = copy_to_user(release, buf, copy + 1);
        }
        return ret;
 }
@@ -2015,7 +2018,6 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
                                break;
                        }
                        me->pdeath_signal = arg2;
-                       error = 0;
                        break;
                case PR_GET_PDEATHSIG:
                        error = put_user(me->pdeath_signal, (int __user *)arg2);
@@ -2029,7 +2031,6 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
                                break;
                        }
                        set_dumpable(me->mm, arg2);
-                       error = 0;
                        break;
 
                case PR_SET_UNALIGN:
@@ -2056,10 +2057,7 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
                case PR_SET_TIMING:
                        if (arg2 != PR_TIMING_STATISTICAL)
                                error = -EINVAL;
-                       else
-                               error = 0;
                        break;
-
                case PR_SET_NAME:
                        comm[sizeof(me->comm)-1] = 0;
                        if (strncpy_from_user(comm, (char __user *)arg2,
@@ -2067,20 +2065,19 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
                                return -EFAULT;
                        set_task_comm(me, comm);
                        proc_comm_connector(me);
-                       return 0;
+                       break;
                case PR_GET_NAME:
                        get_task_comm(comm, me);
                        if (copy_to_user((char __user *)arg2, comm,
                                         sizeof(comm)))
                                return -EFAULT;
-                       return 0;
+                       break;
                case PR_GET_ENDIAN:
                        error = GET_ENDIAN(me, arg2);
                        break;
                case PR_SET_ENDIAN:
                        error = SET_ENDIAN(me, arg2);
                        break;
-
                case PR_GET_SECCOMP:
                        error = prctl_get_seccomp();
                        break;
@@ -2108,7 +2105,6 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
                                        current->default_timer_slack_ns;
                        else
                                current->timer_slack_ns = arg2;
-                       error = 0;
                        break;
                case PR_MCE_KILL:
                        if (arg4 | arg5)
@@ -2134,7 +2130,6 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
                        default:
                                return -EINVAL;
                        }
-                       error = 0;
                        break;
                case PR_MCE_KILL_GET:
                        if (arg2 | arg3 | arg4 | arg5)
@@ -2153,7 +2148,6 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
                        break;
                case PR_SET_CHILD_SUBREAPER:
                        me->signal->is_child_subreaper = !!arg2;
-                       error = 0;
                        break;
                case PR_GET_CHILD_SUBREAPER:
                        error = put_user(me->signal->is_child_subreaper,
@@ -2195,46 +2189,52 @@ static void argv_cleanup(struct subprocess_info *info)
        argv_free(info->argv);
 }
 
-/**
- * orderly_poweroff - Trigger an orderly system poweroff
- * @force: force poweroff if command execution fails
- *
- * This may be called from any context to trigger a system shutdown.
- * If the orderly shutdown fails, it will force an immediate shutdown.
- */
-int orderly_poweroff(bool force)
+static int __orderly_poweroff(void)
 {
        int argc;
-       char **argv = argv_split(GFP_ATOMIC, poweroff_cmd, &argc);
+       char **argv;
        static char *envp[] = {
                "HOME=/",
                "PATH=/sbin:/bin:/usr/sbin:/usr/bin",
                NULL
        };
-       int ret = -ENOMEM;
+       int ret;
 
+       argv = argv_split(GFP_ATOMIC, poweroff_cmd, &argc);
        if (argv == NULL) {
                printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n",
                       __func__, poweroff_cmd);
-               goto out;
+               return -ENOMEM;
        }
 
        ret = call_usermodehelper_fns(argv[0], argv, envp, UMH_NO_WAIT,
                                      NULL, argv_cleanup, NULL);
-out:
-       if (likely(!ret))
-               return 0;
-
        if (ret == -ENOMEM)
                argv_free(argv);
 
-       if (force) {
+       return ret;
+}
+
+/**
+ * orderly_poweroff - Trigger an orderly system poweroff
+ * @force: force poweroff if command execution fails
+ *
+ * This may be called from any context to trigger a system shutdown.
+ * If the orderly shutdown fails, it will force an immediate shutdown.
+ */
+int orderly_poweroff(bool force)
+{
+       int ret = __orderly_poweroff();
+
+       if (ret && force) {
                printk(KERN_WARNING "Failed to start orderly shutdown: "
                       "forcing the issue\n");
 
-               /* I guess this should try to kick off some daemon to
-                  sync and poweroff asap.  Or not even bother syncing
-                  if we're doing an emergency shutdown? */
+               /*
+                * I guess this should try to kick off some daemon to sync and
+                * poweroff asap.  Or not even bother syncing if we're doing an
+                * emergency shutdown?
+                */
                emergency_sync();
                kernel_power_off();
        }