Merge git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus

* git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus:
  stop_machine: fix error code handling on multiple cpus
  stop_machine: use workqueues instead of kernel threads
  workqueue: introduce create_rt_workqueue
  Call init_workqueues before pre smp initcalls.
  Make panic= and panic_on_oops into core_params
  Make initcall_debug a core_param
  core_param() for genuinely core kernel parameters
  param: Fix duplicate module prefixes
  module: check kernel param length at compile time, not runtime
  Remove stop_machine during module load v2
  module: simplify load_module.

9 files changed, 364 insertions, 399 deletions

diff --git a/include/linux/module.h b/include/linux/module.h
index 5d2970cdce9..3bfed013350 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -29,7 +29,7 @@
 #define MODULE_SYMBOL_PREFIX ""
 #endif
 
-#define MODULE_NAME_LEN (64 - sizeof(unsigned long))
+#define MODULE_NAME_LEN MAX_PARAM_PREFIX_LEN
 
 struct kernel_symbol
 {
@@ -60,6 +60,7 @@ struct module_kobject
         struct kobject kobj;
         struct module *mod;
         struct kobject *drivers_dir;
+        struct module_param_attrs *mp;
 };
 
 /* These are either module local, or the kernel's dummy ones. */
@@ -242,7 +243,6 @@ struct module
 
         /* Sysfs stuff. */
         struct module_kobject mkobj;
-        struct module_param_attrs *param_attrs;
         struct module_attribute *modinfo_attrs;
         const char *version;
         const char *srcversion;
@@ -277,7 +277,7 @@ struct module
 
         /* Exception table */
         unsigned int num_exentries;
-        const struct exception_table_entry *extable;
+        struct exception_table_entry *extable;
 
         /* Startup function. */
         int (*init)(void);
diff --git a/include/linux/moduleparam.h b/include/linux/moduleparam.h
index ec624381c84..e4af3399ef4 100644
--- a/include/linux/moduleparam.h
+++ b/include/linux/moduleparam.h
@@ -13,6 +13,9 @@
 #define MODULE_PARAM_PREFIX KBUILD_MODNAME "."
 #endif
 
+/* Chosen so that structs with an unsigned long line up. */
+#define MAX_PARAM_PREFIX_LEN (64 - sizeof(unsigned long))
+
 #ifdef MODULE
 #define ___module_cat(a,b) __mod_ ## a ## b
 #define __module_cat(a,b) ___module_cat(a,b)
@@ -79,7 +82,8 @@ struct kparam_array
 #define __module_param_call(prefix, name, set, get, arg, perm)          \
         /* Default value instead of permissions? */                     \
         static int __param_perm_check_##name __attribute__((unused)) =  \
-        BUILD_BUG_ON_ZERO((perm) < 0 || (perm) > 0777 || ((perm) & 2)); \
+        BUILD_BUG_ON_ZERO((perm) < 0 || (perm) > 0777 || ((perm) & 2))  \
+        + BUILD_BUG_ON_ZERO(sizeof(""prefix) > MAX_PARAM_PREFIX_LEN);   \
         static const char __param_str_##name[] = prefix #name;          \
         static struct kernel_param __moduleparam_const __param_##name   \
         __used                                                          \
@@ -100,6 +104,25 @@ struct kparam_array
 #define module_param(name, type, perm)                          \
         module_param_named(name, name, type, perm)
 
+#ifndef MODULE
+/**
+ * core_param - define a historical core kernel parameter.
+ * @name: the name of the cmdline and sysfs parameter (often the same as var)
+ * @var: the variable
+ * @type: the type (for param_set_##type and param_get_##type)
+ * @perm: visibility in sysfs
+ *
+ * core_param is just like module_param(), but cannot be modular and
+ * doesn't add a prefix (such as "printk.").  This is for compatibility
+ * with __setup(), and it makes sense as truly core parameters aren't
+ * tied to the particular file they're in.
+ */
+#define core_param(name, var, type, perm)                               \
+        param_check_##type(name, &(var));                               \
+        __module_param_call("", name, param_set_##type, param_get_##type, \
+                            &var, perm)
+#endif /* !MODULE */
+
 /* Actually copy string: maxlen param is usually sizeof(string). */
 #define module_param_string(name, string, len, perm)                    \
         static const struct kparam_string __param_string_##name         \
diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h
index 5c158c477ac..89a5a1231ff 100644
--- a/include/linux/workqueue.h
+++ b/include/linux/workqueue.h
@@ -149,11 +149,11 @@ struct execute_work {
 
 extern struct workqueue_struct *
 __create_workqueue_key(const char *name, int singlethread,
-                       int freezeable, struct lock_class_key *key,
+                       int freezeable, int rt, struct lock_class_key *key,
                        const char *lock_name);
 
 #ifdef CONFIG_LOCKDEP
-#define __create_workqueue(name, singlethread, freezeable)      \
+#define __create_workqueue(name, singlethread, freezeable, rt)  \
 ({                                                              \
         static struct lock_class_key __key;                     \
         const char *__lock_name;                                \
@@ -164,17 +164,19 @@ __create_workqueue_key(const char *name, int singlethread,
                 __lock_name = #name;                            \
                                                                 \
         __create_workqueue_key((name), (singlethread),          \
-                               (freezeable), &__key,            \
+                               (freezeable), (rt), &__key,      \
                                __lock_name);                    \
 })
 #else
-#define __create_workqueue(name, singlethread, freezeable)      \
-        __create_workqueue_key((name), (singlethread), (freezeable), NULL, NULL)
+#define __create_workqueue(name, singlethread, freezeable, rt)  \
+        __create_workqueue_key((name), (singlethread), (freezeable), (rt), \
+                               NULL, NULL)
 #endif
 
-#define create_workqueue(name) __create_workqueue((name), 0, 0)
-#define create_freezeable_workqueue(name) __create_workqueue((name), 1, 1)
-#define create_singlethread_workqueue(name) __create_workqueue((name), 1, 0)
+#define create_workqueue(name) __create_workqueue((name), 0, 0, 0)
+#define create_rt_workqueue(name) __create_workqueue((name), 0, 0, 1)
+#define create_freezeable_workqueue(name) __create_workqueue((name), 1, 1, 0)
+#define create_singlethread_workqueue(name) __create_workqueue((name), 1, 0, 0)
 
 extern void destroy_workqueue(struct workqueue_struct *wq);
 
diff --git a/init/main.c b/init/main.c
index 672ae75b205..b038fa14204 100644
--- a/init/main.c
+++ b/init/main.c
@@ -699,13 +699,7 @@ asmlinkage void __init start_kernel(void)
 }
 
 static int initcall_debug;
-
-static int __init initcall_debug_setup(char *str)
-{
-        initcall_debug = 1;
-        return 1;
-}
-__setup("initcall_debug", initcall_debug_setup);
+core_param(initcall_debug, initcall_debug, bool, 0644);
 
 int do_one_initcall(initcall_t fn)
 {
@@ -775,8 +769,6 @@ static void __init do_initcalls(void)
 static void __init do_basic_setup(void)
 {
         rcu_init_sched(); /* needed by module_init stage. */
-        /* drivers will send hotplug events */
-        init_workqueues();
         usermodehelper_init();
         driver_init();
         init_irq_proc();
@@ -860,6 +852,8 @@ static int __init kernel_init(void * unused)
 
         cad_pid = task_pid(current);
 
+        init_workqueues();
+
         smp_prepare_cpus(setup_max_cpus);
 
         do_pre_smp_initcalls();
diff --git a/kernel/module.c b/kernel/module.c
index 0d8d21ee792..c0f1826e2d9 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -42,6 +42,7 @@
 #include <linux/string.h>
 #include <linux/mutex.h>
 #include <linux/unwind.h>
+#include <linux/rculist.h>
 #include <asm/uaccess.h>
 #include <asm/cacheflush.h>
 #include <linux/license.h>
@@ -63,7 +64,7 @@
 #define INIT_OFFSET_MASK (1UL << (BITS_PER_LONG-1))
 
 /* List of modules, protected by module_mutex or preempt_disable
- * (add/delete uses stop_machine). */
+ * (delete uses stop_machine/add uses RCU list operations). */
 static DEFINE_MUTEX(module_mutex);
 static LIST_HEAD(modules);
 
@@ -132,6 +133,29 @@ static unsigned int find_sec(Elf_Ehdr *hdr,
         return 0;
 }
 
+/* Find a module section, or NULL. */
+static void *section_addr(Elf_Ehdr *hdr, Elf_Shdr *shdrs,
+                          const char *secstrings, const char *name)
+{
+        /* Section 0 has sh_addr 0. */
+        return (void *)shdrs[find_sec(hdr, shdrs, secstrings, name)].sh_addr;
+}
+
+/* Find a module section, or NULL.  Fill in number of "objects" in section. */
+static void *section_objs(Elf_Ehdr *hdr,
+                          Elf_Shdr *sechdrs,
+                          const char *secstrings,
+                          const char *name,
+                          size_t object_size,
+                          unsigned int *num)
+{
+        unsigned int sec = find_sec(hdr, sechdrs, secstrings, name);
+
+        /* Section 0 has sh_addr 0 and sh_size 0. */
+        *num = sechdrs[sec].sh_size / object_size;
+        return (void *)sechdrs[sec].sh_addr;
+}
+
 /* Provided by the linker */
 extern const struct kernel_symbol __start___ksymtab[];
 extern const struct kernel_symbol __stop___ksymtab[];
@@ -218,7 +242,7 @@ static bool each_symbol(bool (*fn)(const struct symsearch *arr,
         if (each_symbol_in_section(arr, ARRAY_SIZE(arr), NULL, fn, data))
                 return true;
 
-        list_for_each_entry(mod, &modules, list) {
+        list_for_each_entry_rcu(mod, &modules, list) {
                 struct symsearch arr[] = {
                         { mod->syms, mod->syms + mod->num_syms, mod->crcs,
                           NOT_GPL_ONLY, false },
@@ -1394,17 +1418,6 @@ static void mod_kobject_remove(struct module *mod)
 }
 
 /*
- * link the module with the whole machine is stopped with interrupts off
- * - this defends against kallsyms not taking locks
- */
-static int __link_module(void *_mod)
-{
-        struct module *mod = _mod;
-        list_add(&mod->list, &modules);
-        return 0;
-}
-
-/*
  * unlink the module with the whole machine is stopped with interrupts off
  * - this defends against kallsyms not taking locks
  */
@@ -1789,32 +1802,20 @@ static inline void add_kallsyms(struct module *mod,
 }
 #endif /* CONFIG_KALLSYMS */
 
-#ifdef CONFIG_DYNAMIC_PRINTK_DEBUG
-static void dynamic_printk_setup(Elf_Shdr *sechdrs, unsigned int verboseindex)
+static void dynamic_printk_setup(struct mod_debug *debug, unsigned int num)
 {
-        struct mod_debug *debug_info;
-        unsigned long pos, end;
-        unsigned int num_verbose;
-
-        pos = sechdrs[verboseindex].sh_addr;
-        num_verbose = sechdrs[verboseindex].sh_size /
-                                sizeof(struct mod_debug);
-        end = pos + (num_verbose * sizeof(struct mod_debug));
+#ifdef CONFIG_DYNAMIC_PRINTK_DEBUG
+        unsigned int i;
 
-        for (; pos < end; pos += sizeof(struct mod_debug)) {
-                debug_info = (struct mod_debug *)pos;
-                register_dynamic_debug_module(debug_info->modname,
-                        debug_info->type, debug_info->logical_modname,
-                        debug_info->flag_names, debug_info->hash,
-                        debug_info->hash2);
+        for (i = 0; i < num; i++) {
+                register_dynamic_debug_module(debug[i].modname,
+                                              debug[i].type,
+                                              debug[i].logical_modname,
+                                              debug[i].flag_names,
+                                              debug[i].hash, debug[i].hash2);
         }
-}
-#else
-static inline void dynamic_printk_setup(Elf_Shdr *sechdrs,
-                                        unsigned int verboseindex)
-{
-}
 #endif /* CONFIG_DYNAMIC_PRINTK_DEBUG */
+}
 
 static void *module_alloc_update_bounds(unsigned long size)
 {
@@ -1843,37 +1844,14 @@ static noinline struct module *load_module(void __user *umod,
         unsigned int i;
         unsigned int symindex = 0;
         unsigned int strindex = 0;
-        unsigned int setupindex;
-        unsigned int exindex;
-        unsigned int exportindex;
-        unsigned int modindex;
-        unsigned int obsparmindex;
-        unsigned int infoindex;
-        unsigned int gplindex;
-        unsigned int crcindex;
-        unsigned int gplcrcindex;
-        unsigned int versindex;
-        unsigned int pcpuindex;
-        unsigned int gplfutureindex;
-        unsigned int gplfuturecrcindex;
+        unsigned int modindex, versindex, infoindex, pcpuindex;
         unsigned int unwindex = 0;
-#ifdef CONFIG_UNUSED_SYMBOLS
-        unsigned int unusedindex;
-        unsigned int unusedcrcindex;
-        unsigned int unusedgplindex;
-        unsigned int unusedgplcrcindex;
-#endif
-        unsigned int markersindex;
-        unsigned int markersstringsindex;
-        unsigned int verboseindex;
-        unsigned int tracepointsindex;
-        unsigned int tracepointsstringsindex;
-        unsigned int mcountindex;
+        unsigned int num_kp, num_mcount;
+        struct kernel_param *kp;
         struct module *mod;
         long err = 0;
         void *percpu = NULL, *ptr = NULL; /* Stops spurious gcc warning */
-        void *mseg;
-        struct exception_table_entry *extable;
+        unsigned long *mseg;
         mm_segment_t old_fs;
 
         DEBUGP("load_module: umod=%p, len=%lu, uargs=%p\n",
@@ -1937,6 +1915,7 @@ static noinline struct module *load_module(void __user *umod,
                 err = -ENOEXEC;
                 goto free_hdr;
         }
+        /* This is temporary: point mod into copy of data. */
         mod = (void *)sechdrs[modindex].sh_addr;
 
         if (symindex == 0) {
@@ -1946,22 +1925,6 @@ static noinline struct module *load_module(void __user *umod,
                 goto free_hdr;
         }
 
-        /* Optional sections */
-        exportindex = find_sec(hdr, sechdrs, secstrings, "__ksymtab");
-        gplindex = find_sec(hdr, sechdrs, secstrings, "__ksymtab_gpl");
-        gplfutureindex = find_sec(hdr, sechdrs, secstrings, "__ksymtab_gpl_future");
-        crcindex = find_sec(hdr, sechdrs, secstrings, "__kcrctab");
-        gplcrcindex = find_sec(hdr, sechdrs, secstrings, "__kcrctab_gpl");
-        gplfuturecrcindex = find_sec(hdr, sechdrs, secstrings, "__kcrctab_gpl_future");
-#ifdef CONFIG_UNUSED_SYMBOLS
-        unusedindex = find_sec(hdr, sechdrs, secstrings, "__ksymtab_unused");
-        unusedgplindex = find_sec(hdr, sechdrs, secstrings, "__ksymtab_unused_gpl");
-        unusedcrcindex = find_sec(hdr, sechdrs, secstrings, "__kcrctab_unused");
-        unusedgplcrcindex = find_sec(hdr, sechdrs, secstrings, "__kcrctab_unused_gpl");
-#endif
-        setupindex = find_sec(hdr, sechdrs, secstrings, "__param");
-        exindex = find_sec(hdr, sechdrs, secstrings, "__ex_table");
-        obsparmindex = find_sec(hdr, sechdrs, secstrings, "__obsparm");
         versindex = find_sec(hdr, sechdrs, secstrings, "__versions");
         infoindex = find_sec(hdr, sechdrs, secstrings, ".modinfo");
         pcpuindex = find_pcpusec(hdr, sechdrs, secstrings);
@@ -2117,42 +2080,57 @@ static noinline struct module *load_module(void __user *umod,
         if (err < 0)
                 goto cleanup;
 
-        /* Set up EXPORTed & EXPORT_GPLed symbols (section 0 is 0 length) */
-        mod->num_syms = sechdrs[exportindex].sh_size / sizeof(*mod->syms);
-        mod->syms = (void *)sechdrs[exportindex].sh_addr;
-        if (crcindex)
-                mod->crcs = (void *)sechdrs[crcindex].sh_addr;
-        mod->num_gpl_syms = sechdrs[gplindex].sh_size / sizeof(*mod->gpl_syms);
-        mod->gpl_syms = (void *)sechdrs[gplindex].sh_addr;
-        if (gplcrcindex)
-                mod->gpl_crcs = (void *)sechdrs[gplcrcindex].sh_addr;
-        mod->num_gpl_future_syms = sechdrs[gplfutureindex].sh_size /
-                                        sizeof(*mod->gpl_future_syms);
-        mod->gpl_future_syms = (void *)sechdrs[gplfutureindex].sh_addr;
-        if (gplfuturecrcindex)
-                mod->gpl_future_crcs = (void *)sechdrs[gplfuturecrcindex].sh_addr;
+        /* Now we've got everything in the final locations, we can
+         * find optional sections. */
+        kp = section_objs(hdr, sechdrs, secstrings, "__param", sizeof(*kp),
+                          &num_kp);
+        mod->syms = section_objs(hdr, sechdrs, secstrings, "__ksymtab",
+                                 sizeof(*mod->syms), &mod->num_syms);
+        mod->crcs = section_addr(hdr, sechdrs, secstrings, "__kcrctab");
+        mod->gpl_syms = section_objs(hdr, sechdrs, secstrings, "__ksymtab_gpl",
+                                     sizeof(*mod->gpl_syms),
+                                     &mod->num_gpl_syms);
+        mod->gpl_crcs = section_addr(hdr, sechdrs, secstrings, "__kcrctab_gpl");
+        mod->gpl_future_syms = section_objs(hdr, sechdrs, secstrings,
+                                            "__ksymtab_gpl_future",
+                                            sizeof(*mod->gpl_future_syms),
+                                            &mod->num_gpl_future_syms);
+        mod->gpl_future_crcs = section_addr(hdr, sechdrs, secstrings,
+                                            "__kcrctab_gpl_future");
 
 #ifdef CONFIG_UNUSED_SYMBOLS
-        mod->num_unused_syms = sechdrs[unusedindex].sh_size /
-                                        sizeof(*mod->unused_syms);
-        mod->num_unused_gpl_syms = sechdrs[unusedgplindex].sh_size /
-                                        sizeof(*mod->unused_gpl_syms);
-        mod->unused_syms = (void *)sechdrs[unusedindex].sh_addr;
-        if (unusedcrcindex)
-                mod->unused_crcs = (void *)sechdrs[unusedcrcindex].sh_addr;
-        mod->unused_gpl_syms = (void *)sechdrs[unusedgplindex].sh_addr;
-        if (unusedgplcrcindex)
-                mod->unused_gpl_crcs
-                        = (void *)sechdrs[unusedgplcrcindex].sh_addr;
+        mod->unused_syms = section_objs(hdr, sechdrs, secstrings,
+                                        "__ksymtab_unused",
+                                        sizeof(*mod->unused_syms),
+                                        &mod->num_unused_syms);
+        mod->unused_crcs = section_addr(hdr, sechdrs, secstrings,
+                                        "__kcrctab_unused");
+        mod->unused_gpl_syms = section_objs(hdr, sechdrs, secstrings,
+                                            "__ksymtab_unused_gpl",
+                                            sizeof(*mod->unused_gpl_syms),
+                                            &mod->num_unused_gpl_syms);
+        mod->unused_gpl_crcs = section_addr(hdr, sechdrs, secstrings,
+                                            "__kcrctab_unused_gpl");
+#endif
+
+#ifdef CONFIG_MARKERS
+        mod->markers = section_objs(hdr, sechdrs, secstrings, "__markers",
+                                    sizeof(*mod->markers), &mod->num_markers);
+#endif
+#ifdef CONFIG_TRACEPOINTS
+        mod->tracepoints = section_objs(hdr, sechdrs, secstrings,
+                                        "__tracepoints",
+                                        sizeof(*mod->tracepoints),
+                                        &mod->num_tracepoints);
 #endif
 
 #ifdef CONFIG_MODVERSIONS
-        if ((mod->num_syms && !crcindex)
-            || (mod->num_gpl_syms && !gplcrcindex)
-            || (mod->num_gpl_future_syms && !gplfuturecrcindex)
+        if ((mod->num_syms && !mod->crcs)
+            || (mod->num_gpl_syms && !mod->gpl_crcs)
+            || (mod->num_gpl_future_syms && !mod->gpl_future_crcs)
 #ifdef CONFIG_UNUSED_SYMBOLS
-            || (mod->num_unused_syms && !unusedcrcindex)
-            || (mod->num_unused_gpl_syms && !unusedgplcrcindex)
+            || (mod->num_unused_syms && !mod->unused_crcs)
+            || (mod->num_unused_gpl_syms && !mod->unused_gpl_crcs)
 #endif
                 ) {
                 printk(KERN_WARNING "%s: No versions for exported symbols.\n", mod->name);
@@ -2161,16 +2139,6 @@ static noinline struct module *load_module(void __user *umod,
                         goto cleanup;
         }
 #endif
-        markersindex = find_sec(hdr, sechdrs, secstrings, "__markers");
-        markersstringsindex = find_sec(hdr, sechdrs, secstrings,
-                                        "__markers_strings");
-        verboseindex = find_sec(hdr, sechdrs, secstrings, "__verbose");
-        tracepointsindex = find_sec(hdr, sechdrs, secstrings, "__tracepoints");
-        tracepointsstringsindex = find_sec(hdr, sechdrs, secstrings,
-                                        "__tracepoints_strings");
-
-        mcountindex = find_sec(hdr, sechdrs, secstrings,
-                               "__mcount_loc");
 
         /* Now do relocations. */
         for (i = 1; i < hdr->e_shnum; i++) {
@@ -2193,28 +2161,16 @@ static noinline struct module *load_module(void __user *umod,
                 if (err < 0)
                         goto cleanup;
         }
-#ifdef CONFIG_MARKERS
-        mod->markers = (void *)sechdrs[markersindex].sh_addr;
-        mod->num_markers =
-                sechdrs[markersindex].sh_size / sizeof(*mod->markers);
-#endif
-#ifdef CONFIG_TRACEPOINTS
-        mod->tracepoints = (void *)sechdrs[tracepointsindex].sh_addr;
-        mod->num_tracepoints =
-                sechdrs[tracepointsindex].sh_size / sizeof(*mod->tracepoints);
-#endif
-
 
         /* Find duplicate symbols */
         err = verify_export_symbols(mod);
-
         if (err < 0)
                 goto cleanup;
 
         /* Set up and sort exception table */
-        mod->num_exentries = sechdrs[exindex].sh_size / sizeof(*mod->extable);
-        mod->extable = extable = (void *)sechdrs[exindex].sh_addr;
-        sort_extable(extable, extable + mod->num_exentries);
+        mod->extable = section_objs(hdr, sechdrs, secstrings, "__ex_table",
+                                    sizeof(*mod->extable), &mod->num_exentries);
+        sort_extable(mod->extable, mod->extable + mod->num_exentries);
 
         /* Finally, copy percpu area over. */
         percpu_modcopy(mod->percpu, (void *)sechdrs[pcpuindex].sh_addr,
@@ -2223,11 +2179,17 @@ static noinline struct module *load_module(void __user *umod,
         add_kallsyms(mod, sechdrs, symindex, strindex, secstrings);
 
         if (!mod->taints) {
+                struct mod_debug *debug;
+                unsigned int num_debug;
+
 #ifdef CONFIG_MARKERS
                 marker_update_probe_range(mod->markers,
                         mod->markers + mod->num_markers);
 #endif
-        dynamic_printk_setup(sechdrs, verboseindex);
+                debug = section_objs(hdr, sechdrs, secstrings, "__verbose",
+                                     sizeof(*debug), &num_debug);
+                dynamic_printk_setup(debug, num_debug);
+
 #ifdef CONFIG_TRACEPOINTS
                 tracepoint_update_probe_range(mod->tracepoints,
                         mod->tracepoints + mod->num_tracepoints);
@@ -2235,8 +2197,9 @@ static noinline struct module *load_module(void __user *umod,
         }
 
         /* sechdrs[0].sh_size is always zero */
-        mseg = (void *)sechdrs[mcountindex].sh_addr;
-        ftrace_init_module(mseg, mseg + sechdrs[mcountindex].sh_size);
+        mseg = section_objs(hdr, sechdrs, secstrings, "__mcount_loc",
+                            sizeof(*mseg), &num_mcount);
+        ftrace_init_module(mseg, mseg + num_mcount);
 
         err = module_finalize(hdr, sechdrs, mod);
         if (err < 0)
@@ -2261,30 +2224,24 @@ static noinline struct module *load_module(void __user *umod,
         set_fs(old_fs);
 
         mod->args = args;
-        if (obsparmindex)
+        if (section_addr(hdr, sechdrs, secstrings, "__obsparm"))
                 printk(KERN_WARNING "%s: Ignoring obsolete parameters\n",
                        mod->name);
 
         /* Now sew it into the lists so we can get lockdep and oops
-         * info during argument parsing.  Noone should access us, since
-         * strong_try_module_get() will fail. */
-        stop_machine(__link_module, mod, NULL);
-
-        /* Size of section 0 is 0, so this works well if no params */
-        err = parse_args(mod->name, mod->args,
-                         (struct kernel_param *)
-                         sechdrs[setupindex].sh_addr,
-                         sechdrs[setupindex].sh_size
-                         / sizeof(struct kernel_param),
-                         NULL);
+         * info during argument parsing.  Noone should access us, since
+         * strong_try_module_get() will fail.
+         * lockdep/oops can run asynchronous, so use the RCU list insertion
+         * function to insert in a way safe to concurrent readers.
+         * The mutex protects against concurrent writers.
+         */
+        list_add_rcu(&mod->list, &modules);
+
+        err = parse_args(mod->name, mod->args, kp, num_kp, NULL);
         if (err < 0)
                 goto unlink;
 
-        err = mod_sysfs_setup(mod,
-                              (struct kernel_param *)
-                              sechdrs[setupindex].sh_addr,
-                              sechdrs[setupindex].sh_size
-                              / sizeof(struct kernel_param));
+        err = mod_sysfs_setup(mod, kp, num_kp);
         if (err < 0)
                 goto unlink;
         add_sect_attrs(mod, hdr->e_shnum, secstrings, sechdrs);
@@ -2473,7 +2430,7 @@ const char *module_address_lookup(unsigned long addr,
         const char *ret = NULL;
 
         preempt_disable();
-        list_for_each_entry(mod, &modules, list) {
+        list_for_each_entry_rcu(mod, &modules, list) {
                 if (within(addr, mod->module_init, mod->init_size)
                     || within(addr, mod->module_core, mod->core_size)) {
                         if (modname)
@@ -2496,7 +2453,7 @@ int lookup_module_symbol_name(unsigned long addr, char *symname)
         struct module *mod;
 
         preempt_disable();
-        list_for_each_entry(mod, &modules, list) {
+        list_for_each_entry_rcu(mod, &modules, list) {
                 if (within(addr, mod->module_init, mod->init_size) ||
                     within(addr, mod->module_core, mod->core_size)) {
                         const char *sym;
@@ -2520,7 +2477,7 @@ int lookup_module_symbol_attrs(unsigned long addr, unsigned long *size,
         struct module *mod;
 
         preempt_disable();
-        list_for_each_entry(mod, &modules, list) {
+        list_for_each_entry_rcu(mod, &modules, list) {
                 if (within(addr, mod->module_init, mod->init_size) ||
                     within(addr, mod->module_core, mod->core_size)) {
                         const char *sym;
@@ -2547,7 +2504,7 @@ int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
         struct module *mod;
 
         preempt_disable();
-        list_for_each_entry(mod, &modules, list) {
+        list_for_each_entry_rcu(mod, &modules, list) {
                 if (symnum < mod->num_symtab) {
                         *value = mod->symtab[symnum].st_value;
                         *type = mod->symtab[symnum].st_info;
@@ -2590,7 +2547,7 @@ unsigned long module_kallsyms_lookup_name(const char *name)
                         ret = mod_find_symname(mod, colon+1);
                 *colon = ':';
         } else {
-                list_for_each_entry(mod, &modules, list)
+                list_for_each_entry_rcu(mod, &modules, list)
                         if ((ret = mod_find_symname(mod, name)) != 0)
                                 break;
         }
@@ -2693,7 +2650,7 @@ const struct exception_table_entry *search_module_extables(unsigned long addr)
         struct module *mod;
 
         preempt_disable();
-        list_for_each_entry(mod, &modules, list) {
+        list_for_each_entry_rcu(mod, &modules, list) {
                 if (mod->num_exentries == 0)
                         continue;
 
@@ -2719,7 +2676,7 @@ int is_module_address(unsigned long addr)
 
         preempt_disable();
 
-        list_for_each_entry(mod, &modules, list) {
+        list_for_each_entry_rcu(mod, &modules, list) {
                 if (within(addr, mod->module_core, mod->core_size)) {
                         preempt_enable();
                         return 1;
@@ -2740,7 +2697,7 @@ struct module *__module_text_address(unsigned long addr)
         if (addr < module_addr_min || addr > module_addr_max)
                 return NULL;
 
-        list_for_each_entry(mod, &modules, list)
+        list_for_each_entry_rcu(mod, &modules, list)
                 if (within(addr, mod->module_init, mod->init_text_size)
                     || within(addr, mod->module_core, mod->core_text_size))
                         return mod;
@@ -2765,8 +2722,11 @@ void print_modules(void)
         char buf[8];
 
         printk("Modules linked in:");
-        list_for_each_entry(mod, &modules, list)
+        /* Most callers should already have preempt disabled, but make sure */
+        preempt_disable();
+        list_for_each_entry_rcu(mod, &modules, list)
                 printk(" %s%s", mod->name, module_flags(mod, buf));
+        preempt_enable();
         if (last_unloaded_module[0])
                 printk(" [last unloaded: %s]", last_unloaded_module);
         printk("\n");
diff --git a/kernel/panic.c b/kernel/panic.c
index bda561ef3cd..6513aac8e99 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -34,13 +34,6 @@ ATOMIC_NOTIFIER_HEAD(panic_notifier_list);
 
 EXPORT_SYMBOL(panic_notifier_list);
 
-static int __init panic_setup(char *str)
-{
-        panic_timeout = simple_strtoul(str, NULL, 0);
-        return 1;
-}
-__setup("panic=", panic_setup);
-
 static long no_blink(long time)
 {
         return 0;
@@ -218,13 +211,6 @@ void add_taint(unsigned flag)
 }
 EXPORT_SYMBOL(add_taint);
 
-static int __init pause_on_oops_setup(char *str)
-{
-        pause_on_oops = simple_strtoul(str, NULL, 0);
-        return 1;
-}
-__setup("pause_on_oops=", pause_on_oops_setup);
-
 static void spin_msec(int msecs)
 {
         int i;
@@ -384,3 +370,6 @@ void __stack_chk_fail(void)
 }
 EXPORT_SYMBOL(__stack_chk_fail);
 #endif
+
+core_param(panic, panic_timeout, int, 0644);
+core_param(pause_on_oops, pause_on_oops, int, 0644);
diff --git a/kernel/params.c b/kernel/params.c
index afc46a23eb6..b077f1b045d 100644
--- a/kernel/params.c
+++ b/kernel/params.c
@@ -373,6 +373,8 @@ int param_get_string(char *buffer, struct kernel_param *kp)
 }
 
 /* sysfs output in /sys/modules/XYZ/parameters/ */
+#define to_module_attr(n) container_of(n, struct module_attribute, attr);
+#define to_module_kobject(n) container_of(n, struct module_kobject, kobj);
 
 extern struct kernel_param __start___param[], __stop___param[];
 
@@ -384,6 +386,7 @@ struct param_attribute
 
 struct module_param_attrs
 {
+        unsigned int num;
         struct attribute_group grp;
         struct param_attribute attrs[0];
 };
@@ -434,69 +437,84 @@ static ssize_t param_attr_store(struct module_attribute *mattr,
 
 #ifdef CONFIG_SYSFS
 /*
- * param_sysfs_setup - setup sysfs support for one module or KBUILD_MODNAME
- * @mk: struct module_kobject (contains parent kobject)
- * @kparam: array of struct kernel_param, the actual parameter definitions
- * @num_params: number of entries in array
- * @name_skip: offset where the parameter name start in kparam[].name. Needed for built-in "modules"
+ * add_sysfs_param - add a parameter to sysfs
+ * @mk: struct module_kobject
+ * @kparam: the actual parameter definition to add to sysfs
+ * @name: name of parameter
  *
- * Create a kobject for a (per-module) group of parameters, and create files
- * in sysfs. A pointer to the param_kobject is returned on success,
- * NULL if there's no parameter to export, or other ERR_PTR(err).
+ * Create a kobject if for a (per-module) parameter if mp NULL, and
+ * create file in sysfs.  Returns an error on out of memory.  Always cleans up
+ * if there's an error.
  */
-static __modinit struct module_param_attrs *
-param_sysfs_setup(struct module_kobject *mk,
-                  struct kernel_param *kparam,
-                  unsigned int num_params,
-                  unsigned int name_skip)
+static __modinit int add_sysfs_param(struct module_kobject *mk,
+                                     struct kernel_param *kp,
+                                     const char *name)
 {
-        struct module_param_attrs *mp;
-        unsigned int valid_attrs = 0;
-        unsigned int i, size[2];
-        struct param_attribute *pattr;
-        struct attribute **gattr;
-        int err;
-
-        for (i=0; i<num_params; i++) {
-                if (kparam[i].perm)
-                        valid_attrs++;
+        struct module_param_attrs *new;
+        struct attribute **attrs;
+        int err, num;
+
+        /* We don't bother calling this with invisible parameters. */
+        BUG_ON(!kp->perm);
+
+        if (!mk->mp) {
+                num = 0;
+                attrs = NULL;
+        } else {
+                num = mk->mp->num;
+                attrs = mk->mp->grp.attrs;
         }
 
-        if (!valid_attrs)
-                return NULL;
-
-        size[0] = ALIGN(sizeof(*mp) +
-                        valid_attrs * sizeof(mp->attrs[0]),
-                        sizeof(mp->grp.attrs[0]));
-        size[1] = (valid_attrs + 1) * sizeof(mp->grp.attrs[0]);
-
-        mp = kzalloc(size[0] + size[1], GFP_KERNEL);
-        if (!mp)
-                return ERR_PTR(-ENOMEM);
+        /* Enlarge. */
+        new = krealloc(mk->mp,
+                       sizeof(*mk->mp) + sizeof(mk->mp->attrs[0]) * (num+1),
+                       GFP_KERNEL);
+        if (!new) {
+                kfree(mk->mp);
+                err = -ENOMEM;
+                goto fail;
+        }
+        attrs = krealloc(attrs, sizeof(new->grp.attrs[0])*(num+2), GFP_KERNEL);
+        if (!attrs) {
+                err = -ENOMEM;
+                goto fail_free_new;
+        }
 
-        mp->grp.name = "parameters";
-        mp->grp.attrs = (void *)mp + size[0];
+        /* Sysfs wants everything zeroed. */
+        memset(new, 0, sizeof(*new));
+        memset(&new->attrs[num], 0, sizeof(new->attrs[num]));
+        memset(&attrs[num], 0, sizeof(attrs[num]));
+        new->grp.name = "parameters";
+        new->grp.attrs = attrs;
+
+        /* Tack new one on the end. */
+        new->attrs[num].param = kp;
+        new->attrs[num].mattr.show = param_attr_show;
+        new->attrs[num].mattr.store = param_attr_store;
+        new->attrs[num].mattr.attr.name = (char *)name;
+        new->attrs[num].mattr.attr.mode = kp->perm;
+        new->num = num+1;
+
+        /* Fix up all the pointers, since krealloc can move us */
+        for (num = 0; num < new->num; num++)
+                new->grp.attrs[num] = &new->attrs[num].mattr.attr;
+        new->grp.attrs[num] = NULL;
+
+        mk->mp = new;
+        return 0;
 
-        pattr = &mp->attrs[0];
-        gattr = &mp->grp.attrs[0];
-        for (i = 0; i < num_params; i++) {
-                struct kernel_param *kp = &kparam[i];
-                if (kp->perm) {
-                        pattr->param = kp;
-                        pattr->mattr.show = param_attr_show;
-                        pattr->mattr.store = param_attr_store;
-                        pattr->mattr.attr.name = (char *)&kp->name[name_skip];
-                        pattr->mattr.attr.mode = kp->perm;
-                        *(gattr++) = &(pattr++)->mattr.attr;
-                }
-        }
-        *gattr = NULL;
+fail_free_new:
+        kfree(new);
+fail:
+        mk->mp = NULL;
+        return err;
+}
 
-        if ((err = sysfs_create_group(&mk->kobj, &mp->grp))) {
-                kfree(mp);
-                return ERR_PTR(err);
-        }
-        return mp;
+static void free_module_param_attrs(struct module_kobject *mk)
+{
+        kfree(mk->mp->grp.attrs);
+        kfree(mk->mp);
+        mk->mp = NULL;
 }
 
 #ifdef CONFIG_MODULES
@@ -506,21 +524,33 @@ param_sysfs_setup(struct module_kobject *mk,
  * @kparam: module parameters (array)
  * @num_params: number of module parameters
  *
- * Adds sysfs entries for module parameters, and creates a link from
- * /sys/module/[mod->name]/parameters to /sys/parameters/[mod->name]/
+ * Adds sysfs entries for module parameters under
+ * /sys/module/[mod->name]/parameters/
  */
 int module_param_sysfs_setup(struct module *mod,
                              struct kernel_param *kparam,
                              unsigned int num_params)
 {
-        struct module_param_attrs *mp;
+        int i, err;
+        bool params = false;
+
+        for (i = 0; i < num_params; i++) {
+                if (kparam[i].perm == 0)
+                        continue;
+                err = add_sysfs_param(&mod->mkobj, &kparam[i], kparam[i].name);
+                if (err)
+                        return err;
+                params = true;
+        }
 
-        mp = param_sysfs_setup(&mod->mkobj, kparam, num_params, 0);
-        if (IS_ERR(mp))
-                return PTR_ERR(mp);
+        if (!params)
+                return 0;
 
-        mod->param_attrs = mp;
-        return 0;
+        /* Create the param group. */
+        err = sysfs_create_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
+        if (err)
+                free_module_param_attrs(&mod->mkobj);
+        return err;
 }
 
 /*
@@ -532,43 +562,55 @@ int module_param_sysfs_setup(struct module *mod,
  */
 void module_param_sysfs_remove(struct module *mod)
 {
-        if (mod->param_attrs) {
-                sysfs_remove_group(&mod->mkobj.kobj,
-                                   &mod->param_attrs->grp);
+        if (mod->mkobj.mp) {
+                sysfs_remove_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
                 /* We are positive that no one is using any param
                  * attrs at this point.  Deallocate immediately. */
-                kfree(mod->param_attrs);
-                mod->param_attrs = NULL;
+                free_module_param_attrs(&mod->mkobj);
         }
 }
 #endif
 
-/*
- * kernel_param_sysfs_setup - wrapper for built-in params support
- */
-static void __init kernel_param_sysfs_setup(const char *name,
-                                            struct kernel_param *kparam,
-                                            unsigned int num_params,
-                                            unsigned int name_skip)
+static void __init kernel_add_sysfs_param(const char *name,
+                                          struct kernel_param *kparam,
+                                          unsigned int name_skip)
 {
         struct module_kobject *mk;
-        int ret;
+        struct kobject *kobj;
+        int err;
 
-        mk = kzalloc(sizeof(struct module_kobject), GFP_KERNEL);
-        BUG_ON(!mk);
-
-        mk->mod = THIS_MODULE;
-        mk->kobj.kset = module_kset;
-        ret = kobject_init_and_add(&mk->kobj, &module_ktype, NULL, "%s", name);
-        if (ret) {
-                kobject_put(&mk->kobj);
-                printk(KERN_ERR "Module '%s' failed to be added to sysfs, "
-                      "error number %d\n", name, ret);
-                printk(KERN_ERR "The system will be unstable now.\n");
-                return;
+        kobj = kset_find_obj(module_kset, name);
+        if (kobj) {
+                /* We already have one.  Remove params so we can add more. */
+                mk = to_module_kobject(kobj);
+                /* We need to remove it before adding parameters. */
+                sysfs_remove_group(&mk->kobj, &mk->mp->grp);
+        } else {
+                mk = kzalloc(sizeof(struct module_kobject), GFP_KERNEL);
+                BUG_ON(!mk);
+
+                mk->mod = THIS_MODULE;
+                mk->kobj.kset = module_kset;
+                err = kobject_init_and_add(&mk->kobj, &module_ktype, NULL,
+                                           "%s", name);
+                if (err) {
+                        kobject_put(&mk->kobj);
+                        printk(KERN_ERR "Module '%s' failed add to sysfs, "
+                               "error number %d\n", name, err);
+                        printk(KERN_ERR "The system will be unstable now.\n");
+                        return;
+                }
+                /* So that exit path is even. */
+                kobject_get(&mk->kobj);
         }
-        param_sysfs_setup(mk, kparam, num_params, name_skip);
+
+        /* These should not fail at boot. */
+        err = add_sysfs_param(mk, kparam, kparam->name + name_skip);
+        BUG_ON(err);
+        err = sysfs_create_group(&mk->kobj, &mk->mp->grp);
+        BUG_ON(err);
         kobject_uevent(&mk->kobj, KOBJ_ADD);
+        kobject_put(&mk->kobj);
 }
 
 /*
@@ -579,60 +621,36 @@ static void __init kernel_param_sysfs_setup(const char *name,
  * The "module" name (KBUILD_MODNAME) is stored before a dot, the
  * "parameter" name is stored behind a dot in kernel_param->name. So,
  * extract the "module" name for all built-in kernel_param-eters,
- * and for all who have the same, call kernel_param_sysfs_setup.
+ * and for all who have the same, call kernel_add_sysfs_param.
  */
 static void __init param_sysfs_builtin(void)
 {
-        struct kernel_param *kp, *kp_begin = NULL;
-        unsigned int i, name_len, count = 0;
-        char modname[MODULE_NAME_LEN + 1] = "";
+        struct kernel_param *kp;
+        unsigned int name_len;
+        char modname[MODULE_NAME_LEN];
 
-        for (i=0; i < __stop___param - __start___param; i++) {
+        for (kp = __start___param; kp < __stop___param; kp++) {
                 char *dot;
-                size_t max_name_len;
 
-                kp = &__start___param[i];
-                max_name_len =
-                        min_t(size_t, MODULE_NAME_LEN, strlen(kp->name));
+                if (kp->perm == 0)
+                        continue;
 
-                dot = memchr(kp->name, '.', max_name_len);
+                dot = strchr(kp->name, '.');
                 if (!dot) {
-                        DEBUGP("couldn't find period in first %d characters "
-                               "of %s\n", MODULE_NAME_LEN, kp->name);
-                        continue;
-                }
-                name_len = dot - kp->name;
-
-                /* new kbuild_modname? */
-                if (strlen(modname) != name_len
-                    || strncmp(modname, kp->name, name_len) != 0) {
-                        /* add a new kobject for previous kernel_params. */
-                        if (count)
-                                kernel_param_sysfs_setup(modname,
-                                                         kp_begin,
-                                                         count,
-                                                         strlen(modname)+1);
-
-                        strncpy(modname, kp->name, name_len);
-                        modname[name_len] = '\0';
-                        count = 0;
-                        kp_begin = kp;
+                        /* This happens for core_param() */
+                        strcpy(modname, "kernel");
+                        name_len = 0;
+                } else {
+                        name_len = dot - kp->name + 1;
+                        strlcpy(modname, kp->name, name_len);
                 }
-                count++;
+                kernel_add_sysfs_param(modname, kp, name_len);
         }
-
-        /* last kernel_params need to be registered as well */
-        if (count)
-                kernel_param_sysfs_setup(modname, kp_begin, count,
-                                         strlen(modname)+1);
 }
 
 
 /* module-related sysfs stuff */
 
-#define to_module_attr(n) container_of(n, struct module_attribute, attr);
-#define to_module_kobject(n) container_of(n, struct module_kobject, kobj);
-
 static ssize_t module_attr_show(struct kobject *kobj,
                                 struct attribute *attr,
                                 char *buf)
diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c
index af3c7cea258..8aff79d90dd 100644
--- a/kernel/stop_machine.c
+++ b/kernel/stop_machine.c
@@ -37,9 +37,13 @@ struct stop_machine_data {
 /* Like num_online_cpus(), but hotplug cpu uses us, so we need this. */
 static unsigned int num_threads;
 static atomic_t thread_ack;
-static struct completion finished;
 static DEFINE_MUTEX(lock);
 
+static struct workqueue_struct *stop_machine_wq;
+static struct stop_machine_data active, idle;
+static const cpumask_t *active_cpus;
+static void *stop_machine_work;
+
 static void set_state(enum stopmachine_state newstate)
 {
         /* Reset ack counter. */
@@ -51,21 +55,26 @@ static void set_state(enum stopmachine_state newstate)
 /* Last one to ack a state moves to the next state. */
 static void ack_state(void)
 {
-        if (atomic_dec_and_test(&thread_ack)) {
-                /* If we're the last one to ack the EXIT, we're finished. */
-                if (state == STOPMACHINE_EXIT)
-                        complete(&finished);
-                else
-                        set_state(state + 1);
-        }
+        if (atomic_dec_and_test(&thread_ack))
+                set_state(state + 1);
 }
 
-/* This is the actual thread which stops the CPU.  It exits by itself rather
- * than waiting for kthread_stop(), because it's easier for hotplug CPU. */
-static int stop_cpu(struct stop_machine_data *smdata)
+/* This is the actual function which stops the CPU. It runs
+ * in the context of a dedicated stopmachine workqueue. */
+static void stop_cpu(struct work_struct *unused)
 {
         enum stopmachine_state curstate = STOPMACHINE_NONE;
-
+        struct stop_machine_data *smdata = &idle;
+        int cpu = smp_processor_id();
+        int err;
+
+        if (!active_cpus) {
+                if (cpu == first_cpu(cpu_online_map))
+                        smdata = &active;
+        } else {
+                if (cpu_isset(cpu, *active_cpus))
+                        smdata = &active;
+        }
         /* Simple state machine */
         do {
                 /* Chill out and ensure we re-read stopmachine_state. */
@@ -78,9 +87,11 @@ static int stop_cpu(struct stop_machine_data *smdata)
                                 hard_irq_disable();
                                 break;
                         case STOPMACHINE_RUN:
-                                /* |= allows error detection if functions on
-                                 * multiple CPUs. */
-                                smdata->fnret |= smdata->fn(smdata->data);
+                                /* On multiple CPUs only a single error code
+                                 * is needed to tell that something failed. */
+                                err = smdata->fn(smdata->data);
+                                if (err)
+                                        smdata->fnret = err;
                                 break;
                         default:
                                 break;
@@ -90,7 +101,6 @@ static int stop_cpu(struct stop_machine_data *smdata)
         } while (curstate != STOPMACHINE_EXIT);
 
         local_irq_enable();
-        do_exit(0);
 }
 
 /* Callback for CPUs which aren't supposed to do anything. */
@@ -101,78 +111,34 @@ static int chill(void *unused)
 
 int __stop_machine(int (*fn)(void *), void *data, const cpumask_t *cpus)
 {
-        int i, err;
-        struct stop_machine_data active, idle;
-        struct task_struct **threads;
+        struct work_struct *sm_work;
+        int i;
 
+        /* Set up initial state. */
+        mutex_lock(&lock);
+        num_threads = num_online_cpus();
+        active_cpus = cpus;
         active.fn = fn;
         active.data = data;
         active.fnret = 0;
         idle.fn = chill;
         idle.data = NULL;
 
-        /* This could be too big for stack on large machines. */
-        threads = kcalloc(NR_CPUS, sizeof(threads[0]), GFP_KERNEL);
-        if (!threads)
-                return -ENOMEM;
-
-        /* Set up initial state. */
-        mutex_lock(&lock);
-        init_completion(&finished);
-        num_threads = num_online_cpus();
         set_state(STOPMACHINE_PREPARE);
 
-        for_each_online_cpu(i) {
-                struct stop_machine_data *smdata = &idle;
-                struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 };
-
-                if (!cpus) {
-                        if (i == first_cpu(cpu_online_map))
-                                smdata = &active;
-                } else {
-                        if (cpu_isset(i, *cpus))
-                                smdata = &active;
-                }
-
-                threads[i] = kthread_create((void *)stop_cpu, smdata, "kstop%u",
-                                            i);
-                if (IS_ERR(threads[i])) {
-                        err = PTR_ERR(threads[i]);
-                        threads[i] = NULL;
-                        goto kill_threads;
-                }
-
-                /* Place it onto correct cpu. */
-                kthread_bind(threads[i], i);
-
-                /* Make it highest prio. */
-                if (sched_setscheduler_nocheck(threads[i], SCHED_FIFO, &param))
-                        BUG();
-        }
-
-        /* We've created all the threads.  Wake them all: hold this CPU so one
+        /* Schedule the stop_cpu work on all cpus: hold this CPU so one
          * doesn't hit this CPU until we're ready. */
         get_cpu();
-        for_each_online_cpu(i)
-                wake_up_process(threads[i]);
-
+        for_each_online_cpu(i) {
+                sm_work = percpu_ptr(stop_machine_work, i);
+                INIT_WORK(sm_work, stop_cpu);
+                queue_work_on(i, stop_machine_wq, sm_work);
+        }
         /* This will release the thread on our CPU. */
         put_cpu();
-        wait_for_completion(&finished);
+        flush_workqueue(stop_machine_wq);
         mutex_unlock(&lock);
-
-        kfree(threads);
-
         return active.fnret;
-
-kill_threads:
-        for_each_online_cpu(i)
-                if (threads[i])
-                        kthread_stop(threads[i]);
-        mutex_unlock(&lock);
-
-        kfree(threads);
-        return err;
 }
 
 int stop_machine(int (*fn)(void *), void *data, const cpumask_t *cpus)
@@ -187,3 +153,11 @@ int stop_machine(int (*fn)(void *), void *data, const cpumask_t *cpus)
         return ret;
 }
 EXPORT_SYMBOL_GPL(stop_machine);
+
+static int __init stop_machine_init(void)
+{
+        stop_machine_wq = create_rt_workqueue("kstop");
+        stop_machine_work = alloc_percpu(struct work_struct);
+        return 0;
+}
+early_initcall(stop_machine_init);
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 714afad4653..f928f2a87b9 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -62,6 +62,7 @@ struct workqueue_struct {
         const char *name;
         int singlethread;
         int freezeable;         /* Freeze threads during suspend */
+        int rt;
 #ifdef CONFIG_LOCKDEP
         struct lockdep_map lockdep_map;
 #endif
@@ -766,6 +767,7 @@ init_cpu_workqueue(struct workqueue_struct *wq, int cpu)
 
 static int create_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu)
 {
+        struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 };
         struct workqueue_struct *wq = cwq->wq;
         const char *fmt = is_single_threaded(wq) ? "%s" : "%s/%d";
         struct task_struct *p;
@@ -781,7 +783,8 @@ static int create_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu)
          */
         if (IS_ERR(p))
                 return PTR_ERR(p);
-
+        if (cwq->wq->rt)
+                sched_setscheduler_nocheck(p, SCHED_FIFO, &param);
         cwq->thread = p;
 
         return 0;
@@ -801,6 +804,7 @@ static void start_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu)
 struct workqueue_struct *__create_workqueue_key(const char *name,
                                                 int singlethread,
                                                 int freezeable,
+                                                int rt,
                                                 struct lock_class_key *key,
                                                 const char *lock_name)
 {
@@ -822,6 +826,7 @@ struct workqueue_struct *__create_workqueue_key(const char *name,
         lockdep_init_map(&wq->lockdep_map, lock_name, key, 0);
         wq->singlethread = singlethread;
         wq->freezeable = freezeable;
+        wq->rt = rt;
         INIT_LIST_HEAD(&wq->list);
 
         if (singlethread) {