Merge android-4.4@4b8fc9f (v4.4.82) into msm-4.4

* refs/heads/tmp-4b8fc9f
  UPSTREAM: locking: avoid passing around 'thread_info' in mutex debugging code
  ANDROID: arm64: fix undeclared 'init_thread_info' error
  UPSTREAM: kdb: use task_cpu() instead of task_thread_info()->cpu
  Linux 4.4.82
  net: account for current skb length when deciding about UFO
  ipv4: Should use consistent conditional judgement for ip fragment in __ip_append_data and ip_finish_output
  mm/mempool: avoid KASAN marking mempool poison checks as use-after-free
  KVM: arm/arm64: Handle hva aging while destroying the vm
  sparc64: Prevent perf from running during super critical sections
  udp: consistently apply ufo or fragmentation
  revert "ipv4: Should use consistent conditional judgement for ip fragment in __ip_append_data and ip_finish_output"
  revert "net: account for current skb length when deciding about UFO"
  packet: fix tp_reserve race in packet_set_ring
  net: avoid skb_warn_bad_offload false positives on UFO
  tcp: fastopen: tcp_connect() must refresh the route
  net: sched: set xt_tgchk_param par.nft_compat as 0 in ipt_init_target
  bpf, s390: fix jit branch offset related to ldimm64
  net: fix keepalive code vs TCP_FASTOPEN_CONNECT
  tcp: avoid setting cwnd to invalid ssthresh after cwnd reduction states
  ANDROID: keychord: Fix for a memory leak in keychord.
  ANDROID: keychord: Fix races in keychord_write.
  Use %zu to print resid (size_t).
  ANDROID: keychord: Fix a slab out-of-bounds read.
  Linux 4.4.81
  workqueue: implicit ordered attribute should be overridable
  net: account for current skb length when deciding about UFO
  ipv4: Should use consistent conditional judgement for ip fragment in __ip_append_data and ip_finish_output
  mm: don't dereference struct page fields of invalid pages
  signal: protect SIGNAL_UNKILLABLE from unintentional clearing.
  lib/Kconfig.debug: fix frv build failure
  mm, slab: make sure that KMALLOC_MAX_SIZE will fit into MAX_ORDER
  ARM: 8632/1: ftrace: fix syscall name matching
  virtio_blk: fix panic in initialization error path
  drm/virtio: fix framebuffer sparse warning
  scsi: qla2xxx: Get mutex lock before checking optrom_state
  phy state machine: failsafe leave invalid RUNNING state
  x86/boot: Add missing declaration of string functions
  tg3: Fix race condition in tg3_get_stats64().
  net: phy: dp83867: fix irq generation
  sh_eth: R8A7740 supports packet shecksumming
  wext: handle NULL extra data in iwe_stream_add_point better
  sparc64: Measure receiver forward progress to avoid send mondo timeout
  xen-netback: correctly schedule rate-limited queues
  net: phy: Fix PHY unbind crash
  net: phy: Correctly process PHY_HALTED in phy_stop_machine()
  net/mlx5: Fix command bad flow on command entry allocation failure
  sctp: fix the check for _sctp_walk_params and _sctp_walk_errors
  sctp: don't dereference ptr before leaving _sctp_walk_{params, errors}()
  dccp: fix a memleak for dccp_feat_init err process
  dccp: fix a memleak that dccp_ipv4 doesn't put reqsk properly
  dccp: fix a memleak that dccp_ipv6 doesn't put reqsk properly
  net: ethernet: nb8800: Handle all 4 RGMII modes identically
  ipv6: Don't increase IPSTATS_MIB_FRAGFAILS twice in ip6_fragment()
  packet: fix use-after-free in prb_retire_rx_blk_timer_expired()
  openvswitch: fix potential out of bound access in parse_ct
  mcs7780: Fix initialization when CONFIG_VMAP_STACK is enabled
  rtnetlink: allocate more memory for dev_set_mac_address()
  ipv4: initialize fib_trie prior to register_netdev_notifier call.
  ipv6: avoid overflow of offset in ip6_find_1stfragopt
  net: Zero terminate ifr_name in dev_ifname().
  ipv4: ipv6: initialize treq->txhash in cookie_v[46]_check()
  saa7164: fix double fetch PCIe access condition
  drm: rcar-du: fix backport bug
  f2fs: sanity check checkpoint segno and blkoff
  media: lirc: LIRC_GET_REC_RESOLUTION should return microseconds
  mm, mprotect: flush TLB if potentially racing with a parallel reclaim leaving stale TLB entries
  iser-target: Avoid isert_conn->cm_id dereference in isert_login_recv_done
  iscsi-target: Fix delayed logout processing greater than SECONDS_FOR_LOGOUT_COMP
  iscsi-target: Fix initial login PDU asynchronous socket close OOPs
  iscsi-target: Fix early sk_data_ready LOGIN_FLAGS_READY race
  iscsi-target: Always wait for kthread_should_stop() before kthread exit
  target: Avoid mappedlun symlink creation during lun shutdown
  media: platform: davinci: return -EINVAL for VPFE_CMD_S_CCDC_RAW_PARAMS ioctl
  ARM: dts: armada-38x: Fix irq type for pca955
  ext4: fix overflow caused by missing cast in ext4_resize_fs()
  ext4: fix SEEK_HOLE/SEEK_DATA for blocksize < pagesize
  mm/page_alloc: Remove kernel address exposure in free_reserved_area()
  KVM: async_pf: make rcu irq exit if not triggered from idle task
  ASoC: do not close shared backend dailink
  ALSA: hda - Fix speaker output from VAIO VPCL14M1R
  workqueue: restore WQ_UNBOUND/max_active==1 to be ordered
  libata: array underflow in ata_find_dev()
  ANDROID: binder: don't queue async transactions to thread.
  ANDROID: binder: don't enqueue death notifications to thread todo.
  ANDROID: binder: call poll_wait() unconditionally.
  android: configs: move quota-related configs to recommended
  BACKPORT: arm64: split thread_info from task stack
  UPSTREAM: arm64: assembler: introduce ldr_this_cpu
  UPSTREAM: arm64: make cpu number a percpu variable
  UPSTREAM: arm64: smp: prepare for smp_processor_id() rework
  BACKPORT: arm64: move sp_el0 and tpidr_el1 into cpu_suspend_ctx
  UPSTREAM: arm64: prep stack walkers for THREAD_INFO_IN_TASK
  UPSTREAM: arm64: unexport walk_stackframe
  UPSTREAM: arm64: traps: simplify die() and __die()
  UPSTREAM: arm64: factor out current_stack_pointer
  BACKPORT: arm64: asm-offsets: remove unused definitions
  UPSTREAM: arm64: thread_info remove stale items
  UPSTREAM: thread_info: include <current.h> for THREAD_INFO_IN_TASK
  UPSTREAM: thread_info: factor out restart_block
  UPSTREAM: kthread: Pin the stack via try_get_task_stack()/put_task_stack() in to_live_kthread() function
  UPSTREAM: sched/core: Add try_get_task_stack() and put_task_stack()
  UPSTREAM: sched/core: Allow putting thread_info into task_struct
  UPSTREAM: printk: when dumping regs, show the stack, not thread_info
  UPSTREAM: fix up initial thread stack pointer vs thread_info confusion
  UPSTREAM: Clarify naming of thread info/stack allocators
  ANDROID: sdcardfs: override credential for ioctl to lower fs

Conflicts:
	android/configs/android-base.cfg
	arch/arm64/Kconfig
	arch/arm64/include/asm/suspend.h
	arch/arm64/kernel/head.S
	arch/arm64/kernel/smp.c
	arch/arm64/kernel/suspend.c
	arch/arm64/kernel/traps.c
	arch/arm64/mm/proc.S
	kernel/fork.c
	sound/soc/soc-pcm.c

Change-Id: I273e216c94899a838bbd208391c6cbe20b2bf683
Signed-off-by: Blagovest Kolenichev <bkolenichev@codeaurora.org>

10 files changed, 73 insertions, 49 deletions

diff --git a/kernel/fork.c b/kernel/fork.c
index fef4df444f47..07cd0d68ee02 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -148,18 +148,18 @@ static inline void free_task_struct(struct task_struct *tsk)
 }
 #endif
 
-void __weak arch_release_thread_info(struct thread_info *ti)
+void __weak arch_release_thread_stack(unsigned long *stack)
 {
 }
 
-#ifndef CONFIG_ARCH_THREAD_INFO_ALLOCATOR
+#ifndef CONFIG_ARCH_THREAD_STACK_ALLOCATOR
 
 /*
  * Allocate pages if THREAD_SIZE is >= PAGE_SIZE, otherwise use a
  * kmemcache based allocator.
  */
 # if THREAD_SIZE >= PAGE_SIZE
-static struct thread_info *alloc_thread_info_node(struct task_struct *tsk,
+static unsigned long *alloc_thread_stack_node(struct task_struct *tsk,
 						  int node)
 {
 	struct page *page = alloc_kmem_pages_node(node, THREADINFO_GFP,
@@ -168,30 +168,32 @@ static struct thread_info *alloc_thread_info_node(struct task_struct *tsk,
 	return page ? page_address(page) : NULL;
 }
 
-static inline void free_thread_info(struct thread_info *ti)
+static inline void free_thread_stack(unsigned long *stack)
 {
-	kasan_alloc_pages(virt_to_page(ti), THREAD_SIZE_ORDER);
-	free_kmem_pages((unsigned long)ti, THREAD_SIZE_ORDER);
+	struct page *page = virt_to_page(stack);
+
+	kasan_alloc_pages(page, THREAD_SIZE_ORDER);
+	__free_kmem_pages(page, THREAD_SIZE_ORDER);
 }
 # else
-static struct kmem_cache *thread_info_cache;
+static struct kmem_cache *thread_stack_cache;
 
-static struct thread_info *alloc_thread_info_node(struct task_struct *tsk,
+static struct thread_info *alloc_thread_stack_node(struct task_struct *tsk,
 						  int node)
 {
-	return kmem_cache_alloc_node(thread_info_cache, THREADINFO_GFP, node);
+	return kmem_cache_alloc_node(thread_stack_cache, THREADINFO_GFP, node);
 }
 
-static void free_thread_info(struct thread_info *ti)
+static void free_stack(unsigned long *stack)
 {
-	kmem_cache_free(thread_info_cache, ti);
+	kmem_cache_free(thread_stack_cache, stack);
 }
 
-void thread_info_cache_init(void)
+void thread_stack_cache_init(void)
 {
-	thread_info_cache = kmem_cache_create("thread_info", THREAD_SIZE,
+	thread_stack_cache = kmem_cache_create("thread_stack", THREAD_SIZE,
 					      THREAD_SIZE, 0, NULL);
-	BUG_ON(thread_info_cache == NULL);
+	BUG_ON(thread_stack_cache == NULL);
 }
 # endif
 #endif
@@ -214,9 +216,9 @@ struct kmem_cache *vm_area_cachep;
 /* SLAB cache for mm_struct structures (tsk->mm) */
 static struct kmem_cache *mm_cachep;
 
-static void account_kernel_stack(struct thread_info *ti, int account)
+static void account_kernel_stack(unsigned long *stack, int account)
 {
-	struct zone *zone = page_zone(virt_to_page(ti));
+	struct zone *zone = page_zone(virt_to_page(stack));
 
 	mod_zone_page_state(zone, NR_KERNEL_STACK, account);
 }
@@ -224,8 +226,8 @@ static void account_kernel_stack(struct thread_info *ti, int account)
 void free_task(struct task_struct *tsk)
 {
 	account_kernel_stack(tsk->stack, -1);
-	arch_release_thread_info(tsk->stack);
-	free_thread_info(tsk->stack);
+	arch_release_thread_stack(tsk->stack);
+	free_thread_stack(tsk->stack);
 	rt_mutex_debug_task_free(tsk);
 	ftrace_graph_exit_task(tsk);
 	put_seccomp_filter(tsk);
@@ -336,7 +338,7 @@ void set_task_stack_end_magic(struct task_struct *tsk)
 static struct task_struct *dup_task_struct(struct task_struct *orig, int node)
 {
 	struct task_struct *tsk;
-	struct thread_info *ti;
+	unsigned long *stack;
 	int err;
 
 	if (node == NUMA_NO_NODE)
@@ -345,15 +347,15 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node)
 	if (!tsk)
 		return NULL;
 
-	ti = alloc_thread_info_node(tsk, node);
-	if (!ti)
+	stack = alloc_thread_stack_node(tsk, node);
+	if (!stack)
 		goto free_tsk;
 
 	err = arch_dup_task_struct(tsk, orig);
 	if (err)
-		goto free_ti;
+		goto free_stack;
 
-	tsk->stack = ti;
+	tsk->stack = stack;
 #ifdef CONFIG_SECCOMP
 	/*
 	 * We must handle setting up seccomp filters once we're under
@@ -385,12 +387,12 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node)
 	tsk->task_frag.page = NULL;
 	tsk->wake_q.next = NULL;
 
-	account_kernel_stack(ti, 1);
+	account_kernel_stack(stack, 1);
 
 	return tsk;
 
-free_ti:
-	free_thread_info(ti);
+free_stack:
+	free_thread_stack(stack);
 free_tsk:
 	free_task_struct(tsk);
 	return NULL;
diff --git a/kernel/kthread.c b/kernel/kthread.c
index 698b8dec3074..d9b0be5c6a5f 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -65,7 +65,7 @@ static inline struct kthread *to_kthread(struct task_struct *k)
 static struct kthread *to_live_kthread(struct task_struct *k)
 {
 	struct completion *vfork = ACCESS_ONCE(k->vfork_done);
-	if (likely(vfork))
+	if (likely(vfork) && try_get_task_stack(k))
 		return __to_kthread(vfork);
 	return NULL;
 }
@@ -427,8 +427,10 @@ void kthread_unpark(struct task_struct *k)
 {
 	struct kthread *kthread = to_live_kthread(k);
 
-	if (kthread)
+	if (kthread) {
 		__kthread_unpark(k, kthread);
+		put_task_stack(k);
+	}
 }
 EXPORT_SYMBOL_GPL(kthread_unpark);
 
@@ -457,6 +459,7 @@ int kthread_park(struct task_struct *k)
 				wait_for_completion(&kthread->parked);
 			}
 		}
+		put_task_stack(k);
 		ret = 0;
 	}
 	return ret;
@@ -492,6 +495,7 @@ int kthread_stop(struct task_struct *k)
 		__kthread_unpark(k, kthread);
 		wake_up_process(k);
 		wait_for_completion(&kthread->exited);
+		put_task_stack(k);
 	}
 	ret = k->exit_code;
 	put_task_struct(k);
diff --git a/kernel/locking/mutex-debug.c b/kernel/locking/mutex-debug.c
index 3ef3736002d8..9c951fade415 100644
--- a/kernel/locking/mutex-debug.c
+++ b/kernel/locking/mutex-debug.c
@@ -49,21 +49,21 @@ void debug_mutex_free_waiter(struct mutex_waiter *waiter)
 }
 
 void debug_mutex_add_waiter(struct mutex *lock, struct mutex_waiter *waiter,
-			    struct thread_info *ti)
+			    struct task_struct *task)
 {
 	SMP_DEBUG_LOCKS_WARN_ON(!spin_is_locked(&lock->wait_lock));
 
 	/* Mark the current thread as blocked on the lock: */
-	ti->task->blocked_on = waiter;
+	task->blocked_on = waiter;
 }
 
 void mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter,
-			 struct thread_info *ti)
+			 struct task_struct *task)
 {
 	DEBUG_LOCKS_WARN_ON(list_empty(&waiter->list));
-	DEBUG_LOCKS_WARN_ON(waiter->task != ti->task);
-	DEBUG_LOCKS_WARN_ON(ti->task->blocked_on != waiter);
-	ti->task->blocked_on = NULL;
+	DEBUG_LOCKS_WARN_ON(waiter->task != task);
+	DEBUG_LOCKS_WARN_ON(task->blocked_on != waiter);
+	task->blocked_on = NULL;
 
 	list_del_init(&waiter->list);
 	waiter->task = NULL;
diff --git a/kernel/locking/mutex-debug.h b/kernel/locking/mutex-debug.h
index 0799fd3e4cfa..d06ae3bb46c5 100644
--- a/kernel/locking/mutex-debug.h
+++ b/kernel/locking/mutex-debug.h
@@ -20,9 +20,9 @@ extern void debug_mutex_wake_waiter(struct mutex *lock,
 extern void debug_mutex_free_waiter(struct mutex_waiter *waiter);
 extern void debug_mutex_add_waiter(struct mutex *lock,
 				   struct mutex_waiter *waiter,
-				   struct thread_info *ti);
+				   struct task_struct *task);
 extern void mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter,
-				struct thread_info *ti);
+				struct task_struct *task);
 extern void debug_mutex_unlock(struct mutex *lock);
 extern void debug_mutex_init(struct mutex *lock, const char *name,
 			     struct lock_class_key *key);
diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c
index 14b9cca36b05..bf5277ee11d3 100644
--- a/kernel/locking/mutex.c
+++ b/kernel/locking/mutex.c
@@ -549,7 +549,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
 		goto skip_wait;
 
 	debug_mutex_lock_common(lock, &waiter);
-	debug_mutex_add_waiter(lock, &waiter, task_thread_info(task));
+	debug_mutex_add_waiter(lock, &waiter, task);
 
 	/* add waiting tasks to the end of the waitqueue (FIFO): */
 	list_add_tail(&waiter.list, &lock->wait_list);
@@ -596,7 +596,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
 	}
 	__set_task_state(task, TASK_RUNNING);
 
-	mutex_remove_waiter(lock, &waiter, current_thread_info());
+	mutex_remove_waiter(lock, &waiter, task);
 	/* set it to 0 if there are no waiters left: */
 	if (likely(list_empty(&lock->wait_list)))
 		atomic_set(&lock->count, 0);
@@ -617,7 +617,7 @@ skip_wait:
 	return 0;
 
 err:
-	mutex_remove_waiter(lock, &waiter, task_thread_info(task));
+	mutex_remove_waiter(lock, &waiter, task);
 	spin_unlock_mutex(&lock->wait_lock, flags);
 	debug_mutex_free_waiter(&waiter);
 	mutex_release(&lock->dep_map, 1, ip);
diff --git a/kernel/locking/mutex.h b/kernel/locking/mutex.h
index 5cda397607f2..a68bae5e852a 100644
--- a/kernel/locking/mutex.h
+++ b/kernel/locking/mutex.h
@@ -13,7 +13,7 @@
 		do { spin_lock(lock); (void)(flags); } while (0)
 #define spin_unlock_mutex(lock, flags) \
 		do { spin_unlock(lock); (void)(flags); } while (0)
-#define mutex_remove_waiter(lock, waiter, ti) \
+#define mutex_remove_waiter(lock, waiter, task) \
 		__list_del((waiter)->list.prev, (waiter)->list.next)
 
 #ifdef CONFIG_MUTEX_SPIN_ON_OWNER
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 9fcb521fab0e..dca87791e9c1 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -3180,9 +3180,8 @@ void show_regs_print_info(const char *log_lvl)
 {
 	dump_stack_print_info(log_lvl);
 
-	printk("%stask: %p ti: %p task.ti: %p\n",
-	       log_lvl, current, current_thread_info(),
-	       task_thread_info(current));
+	printk("%stask: %p task.stack: %p\n",
+	       log_lvl, current, task_stack_page(current));
 }
 
 #endif
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 67b7da81f8a2..33bf0c07e757 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -1767,7 +1767,11 @@ static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu)
 	 * per-task data have been completed by this moment.
 	 */
 	smp_wmb();
+#ifdef CONFIG_THREAD_INFO_IN_TASK
+	p->cpu = cpu;
+#else
 	task_thread_info(p)->cpu = cpu;
+#endif
 	p->wake_cpu = cpu;
 #endif
 }
diff --git a/kernel/signal.c b/kernel/signal.c
index b92a047ddc82..5d50ea899b6d 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -346,7 +346,7 @@ static bool task_participate_group_stop(struct task_struct *task)
 	 * fresh group stop.  Read comment in do_signal_stop() for details.
 	 */
 	if (!sig->group_stop_count && !(sig->flags & SIGNAL_STOP_STOPPED)) {
-		sig->flags = SIGNAL_STOP_STOPPED;
+		signal_set_stop_flags(sig, SIGNAL_STOP_STOPPED);
 		return true;
 	}
 	return false;
@@ -845,7 +845,7 @@ static bool prepare_signal(int sig, struct task_struct *p, bool force)
 			 * will take ->siglock, notice SIGNAL_CLD_MASK, and
 			 * notify its parent. See get_signal_to_deliver().
 			 */
-			signal->flags = why | SIGNAL_STOP_CONTINUED;
+			signal_set_stop_flags(signal, why | SIGNAL_STOP_CONTINUED);
 			signal->group_stop_count = 0;
 			signal->group_exit_code = 0;
 		}
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 73c018d7df00..80b5dbfd187d 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -3669,8 +3669,12 @@ static int apply_workqueue_attrs_locked(struct workqueue_struct *wq,
 		return -EINVAL;
 
 	/* creating multiple pwqs breaks ordering guarantee */
-	if (WARN_ON((wq->flags & __WQ_ORDERED) && !list_empty(&wq->pwqs)))
-		return -EINVAL;
+	if (!list_empty(&wq->pwqs)) {
+		if (WARN_ON(wq->flags & __WQ_ORDERED_EXPLICIT))
+			return -EINVAL;
+
+		wq->flags &= ~__WQ_ORDERED;
+	}
 
 	ctx = apply_wqattrs_prepare(wq, attrs);
 
@@ -3856,6 +3860,16 @@ struct workqueue_struct *__alloc_workqueue_key(const char *fmt,
 	struct workqueue_struct *wq;
 	struct pool_workqueue *pwq;
 
+	/*
+	 * Unbound && max_active == 1 used to imply ordered, which is no
+	 * longer the case on NUMA machines due to per-node pools.  While
+	 * alloc_ordered_workqueue() is the right way to create an ordered
+	 * workqueue, keep the previous behavior to avoid subtle breakages
+	 * on NUMA.
+	 */
+	if ((flags & WQ_UNBOUND) && max_active == 1)
+		flags |= __WQ_ORDERED;
+
 	/* see the comment above the definition of WQ_POWER_EFFICIENT */
 	if ((flags & WQ_POWER_EFFICIENT) && wq_power_efficient)
 		flags |= WQ_UNBOUND;
@@ -4044,13 +4058,14 @@ void workqueue_set_max_active(struct workqueue_struct *wq, int max_active)
 	struct pool_workqueue *pwq;
 
 	/* disallow meddling with max_active for ordered workqueues */
-	if (WARN_ON(wq->flags & __WQ_ORDERED))
+	if (WARN_ON(wq->flags & __WQ_ORDERED_EXPLICIT))
 		return;
 
 	max_active = wq_clamp_max_active(max_active, wq->flags, wq->name);
 
 	mutex_lock(&wq->mutex);
 
+	wq->flags &= ~__WQ_ORDERED;
 	wq->saved_max_active = max_active;
 
 	for_each_pwq(pwq, wq)
@@ -5178,7 +5193,7 @@ int workqueue_sysfs_register(struct workqueue_struct *wq)
 	 * attributes breaks ordering guarantee.  Disallow exposing ordered
 	 * workqueues.
 	 */
-	if (WARN_ON(wq->flags & __WQ_ORDERED))
+	if (WARN_ON(wq->flags & __WQ_ORDERED_EXPLICIT))
 		return -EINVAL;
 
 	wq->wq_dev = wq_dev = kzalloc(sizeof(*wq_dev), GFP_KERNEL);