* Re: Linux 3.4.99
2014-07-17 23:43 Linux 3.4.99 Greg KH
@ 2014-07-17 23:43 ` Greg KH
0 siblings, 0 replies; 2+ messages in thread
From: Greg KH @ 2014-07-17 23:43 UTC (permalink / raw)
To: linux-kernel, Andrew Morton, torvalds, stable; +Cc: lwn, Jiri Slaby
diff --git a/Makefile b/Makefile
index d277446ee8ee..ed97caf40f71 100644
--- a/Makefile
+++ b/Makefile
@@ -1,6 +1,6 @@
VERSION = 3
PATCHLEVEL = 4
-SUBLEVEL = 98
+SUBLEVEL = 99
EXTRAVERSION =
NAME = Saber-toothed Squirrel
diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c
index 02aee03e713c..1eef567f177a 100644
--- a/arch/powerpc/perf/core-book3s.c
+++ b/arch/powerpc/perf/core-book3s.c
@@ -472,7 +472,22 @@ static void power_pmu_read(struct perf_event *event)
} while (local64_cmpxchg(&event->hw.prev_count, prev, val) != prev);
local64_add(delta, &event->count);
- local64_sub(delta, &event->hw.period_left);
+
+ /*
+ * A number of places program the PMC with (0x80000000 - period_left).
+ * We never want period_left to be less than 1 because we will program
+ * the PMC with a value >= 0x800000000 and an edge detected PMC will
+ * roll around to 0 before taking an exception. We have seen this
+ * on POWER8.
+ *
+ * To fix this, clamp the minimum value of period_left to 1.
+ */
+ do {
+ prev = local64_read(&event->hw.period_left);
+ val = prev - delta;
+ if (val < 1)
+ val = 1;
+ } while (local64_cmpxchg(&event->hw.period_left, prev, val) != prev);
}
/*
diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index be1ef574ce9a..dec49d34c048 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -50,6 +50,21 @@ int ioremap_change_attr(unsigned long vaddr, unsigned long size,
return err;
}
+static int __ioremap_check_ram(unsigned long start_pfn, unsigned long nr_pages,
+ void *arg)
+{
+ unsigned long i;
+
+ for (i = 0; i < nr_pages; ++i)
+ if (pfn_valid(start_pfn + i) &&
+ !PageReserved(pfn_to_page(start_pfn + i)))
+ return 1;
+
+ WARN_ONCE(1, "ioremap on RAM pfn 0x%lx\n", start_pfn);
+
+ return 0;
+}
+
/*
* Remap an arbitrary physical address space into the kernel virtual
* address space. Needed when the kernel wants to access high addresses
@@ -93,14 +108,11 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr,
/*
* Don't allow anybody to remap normal RAM that we're using..
*/
+ pfn = phys_addr >> PAGE_SHIFT;
last_pfn = last_addr >> PAGE_SHIFT;
- for (pfn = phys_addr >> PAGE_SHIFT; pfn <= last_pfn; pfn++) {
- int is_ram = page_is_ram(pfn);
-
- if (is_ram && pfn_valid(pfn) && !PageReserved(pfn_to_page(pfn)))
- return NULL;
- WARN_ON_ONCE(is_ram);
- }
+ if (walk_system_ram_range(pfn, last_pfn - pfn + 1, NULL,
+ __ioremap_check_ram) == 1)
+ return NULL;
/*
* Mappings have to be page-aligned
diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c
index 9bdfcf50a190..93f3034ea85d 100644
--- a/drivers/acpi/battery.c
+++ b/drivers/acpi/battery.c
@@ -34,6 +34,7 @@
#include <linux/dmi.h>
#include <linux/slab.h>
#include <linux/suspend.h>
+#include <linux/delay.h>
#include <asm/unaligned.h>
#ifdef CONFIG_ACPI_PROCFS_POWER
@@ -1055,6 +1056,28 @@ static int battery_notify(struct notifier_block *nb,
return 0;
}
+/*
+ * Some machines'(E,G Lenovo Z480) ECs are not stable
+ * during boot up and this causes battery driver fails to be
+ * probed due to failure of getting battery information
+ * from EC sometimes. After several retries, the operation
+ * may work. So add retry code here and 20ms sleep between
+ * every retries.
+ */
+static int acpi_battery_update_retry(struct acpi_battery *battery)
+{
+ int retry, ret;
+
+ for (retry = 5; retry; retry--) {
+ ret = acpi_battery_update(battery);
+ if (!ret)
+ break;
+
+ msleep(20);
+ }
+ return ret;
+}
+
static int acpi_battery_add(struct acpi_device *device)
{
int result = 0;
@@ -1074,9 +1097,11 @@ static int acpi_battery_add(struct acpi_device *device)
if (ACPI_SUCCESS(acpi_get_handle(battery->device->handle,
"_BIX", &handle)))
set_bit(ACPI_BATTERY_XINFO_PRESENT, &battery->flags);
- result = acpi_battery_update(battery);
+
+ result = acpi_battery_update_retry(battery);
if (result)
goto fail;
+
#ifdef CONFIG_ACPI_PROCFS_POWER
result = acpi_battery_add_fs(device);
#endif
diff --git a/drivers/gpu/drm/radeon/rs600.c b/drivers/gpu/drm/radeon/rs600.c
index 52480010156d..739eb0d0d12d 100644
--- a/drivers/gpu/drm/radeon/rs600.c
+++ b/drivers/gpu/drm/radeon/rs600.c
@@ -539,8 +539,10 @@ int rs600_gart_set_page(struct radeon_device *rdev, int i, uint64_t addr)
return -EINVAL;
}
addr = addr & 0xFFFFFFFFFFFFF000ULL;
- addr |= R600_PTE_VALID | R600_PTE_SYSTEM | R600_PTE_SNOOPED;
- addr |= R600_PTE_READABLE | R600_PTE_WRITEABLE;
+ if (addr != rdev->dummy_page.addr)
+ addr |= R600_PTE_VALID | R600_PTE_READABLE |
+ R600_PTE_WRITEABLE;
+ addr |= R600_PTE_SYSTEM | R600_PTE_SNOOPED;
writeq(addr, ptr + (i * 8));
return 0;
}
diff --git a/drivers/hwmon/adm1029.c b/drivers/hwmon/adm1029.c
index 80cc465d8ac7..f078baef90fe 100644
--- a/drivers/hwmon/adm1029.c
+++ b/drivers/hwmon/adm1029.c
@@ -231,6 +231,9 @@ static ssize_t set_fan_div(struct device *dev,
/* Update the value */
reg = (reg & 0x3F) | (val << 6);
+ /* Update the cache */
+ data->fan_div[attr->index] = reg;
+
/* Write value */
i2c_smbus_write_byte_data(client,
ADM1029_REG_FAN_DIV[attr->index], reg);
diff --git a/drivers/hwmon/amc6821.c b/drivers/hwmon/amc6821.c
index f600fa1f92e3..1d2bace45287 100644
--- a/drivers/hwmon/amc6821.c
+++ b/drivers/hwmon/amc6821.c
@@ -715,7 +715,7 @@ static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO,
get_temp_alarm, NULL, IDX_TEMP1_MAX);
static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO,
get_temp_alarm, NULL, IDX_TEMP1_CRIT);
-static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO | S_IWUSR,
+static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO,
get_temp, NULL, IDX_TEMP2_INPUT);
static SENSOR_DEVICE_ATTR(temp2_min, S_IRUGO | S_IWUSR, get_temp,
set_temp, IDX_TEMP2_MIN);
diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
index 3bd9bd49ed9a..ac339570a805 100644
--- a/drivers/usb/serial/cp210x.c
+++ b/drivers/usb/serial/cp210x.c
@@ -159,6 +159,7 @@ static const struct usb_device_id id_table[] = {
{ USB_DEVICE(0x1843, 0x0200) }, /* Vaisala USB Instrument Cable */
{ USB_DEVICE(0x18EF, 0xE00F) }, /* ELV USB-I2C-Interface */
{ USB_DEVICE(0x1ADB, 0x0001) }, /* Schweitzer Engineering C662 Cable */
+ { USB_DEVICE(0x1B1C, 0x1C00) }, /* Corsair USB Dongle */
{ USB_DEVICE(0x1BE3, 0x07A6) }, /* WAGO 750-923 USB Service Cable */
{ USB_DEVICE(0x1E29, 0x0102) }, /* Festo CPX-USB */
{ USB_DEVICE(0x1E29, 0x0501) }, /* Festo CMSP */
diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c
index ed1650fb910d..89b5664aa53b 100644
--- a/drivers/usb/serial/ftdi_sio.c
+++ b/drivers/usb/serial/ftdi_sio.c
@@ -731,7 +731,8 @@ static struct usb_device_id id_table_combined [] = {
{ USB_DEVICE(FTDI_VID, FTDI_ACG_HFDUAL_PID) },
{ USB_DEVICE(FTDI_VID, FTDI_YEI_SERVOCENTER31_PID) },
{ USB_DEVICE(FTDI_VID, FTDI_THORLABS_PID) },
- { USB_DEVICE(TESTO_VID, TESTO_USB_INTERFACE_PID) },
+ { USB_DEVICE(TESTO_VID, TESTO_1_PID) },
+ { USB_DEVICE(TESTO_VID, TESTO_3_PID) },
{ USB_DEVICE(FTDI_VID, FTDI_GAMMA_SCOUT_PID) },
{ USB_DEVICE(FTDI_VID, FTDI_TACTRIX_OPENPORT_13M_PID) },
{ USB_DEVICE(FTDI_VID, FTDI_TACTRIX_OPENPORT_13S_PID) },
diff --git a/drivers/usb/serial/ftdi_sio_ids.h b/drivers/usb/serial/ftdi_sio_ids.h
index 500474c48f4b..106cc16cc6ed 100644
--- a/drivers/usb/serial/ftdi_sio_ids.h
+++ b/drivers/usb/serial/ftdi_sio_ids.h
@@ -798,7 +798,8 @@
* Submitted by Colin Leroy
*/
#define TESTO_VID 0x128D
-#define TESTO_USB_INTERFACE_PID 0x0001
+#define TESTO_1_PID 0x0001
+#define TESTO_3_PID 0x0003
/*
* Mobility Electronics products.
diff --git a/drivers/usb/serial/option.c b/drivers/usb/serial/option.c
index 58fcaa5ae548..e1e05bad2be0 100644
--- a/drivers/usb/serial/option.c
+++ b/drivers/usb/serial/option.c
@@ -1501,6 +1501,8 @@ static const struct usb_device_id option_ids[] = {
.driver_info = (kernel_ulong_t)&net_intf2_blacklist },
{ USB_DEVICE_AND_INTERFACE_INFO(ZTE_VENDOR_ID, 0x1426, 0xff, 0xff, 0xff), /* ZTE MF91 */
.driver_info = (kernel_ulong_t)&net_intf2_blacklist },
+ { USB_DEVICE_AND_INTERFACE_INFO(ZTE_VENDOR_ID, 0x1428, 0xff, 0xff, 0xff), /* Telewell TW-LTE 4G v2 */
+ .driver_info = (kernel_ulong_t)&net_intf2_blacklist },
{ USB_DEVICE_AND_INTERFACE_INFO(ZTE_VENDOR_ID, 0x1533, 0xff, 0xff, 0xff) },
{ USB_DEVICE_AND_INTERFACE_INFO(ZTE_VENDOR_ID, 0x1534, 0xff, 0xff, 0xff) },
{ USB_DEVICE_AND_INTERFACE_INFO(ZTE_VENDOR_ID, 0x1535, 0xff, 0xff, 0xff) },
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 0b0c03c878e5..f0e4e46867f7 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -2589,10 +2589,11 @@ static void print_daily_error_info(unsigned long arg)
es = sbi->s_es;
if (es->s_error_count)
- ext4_msg(sb, KERN_NOTICE, "error count: %u",
+ /* fsck newer than v1.41.13 is needed to clean this condition. */
+ ext4_msg(sb, KERN_NOTICE, "error count since last fsck: %u",
le32_to_cpu(es->s_error_count));
if (es->s_first_error_time) {
- printk(KERN_NOTICE "EXT4-fs (%s): initial error at %u: %.*s:%d",
+ printk(KERN_NOTICE "EXT4-fs (%s): initial error at time %u: %.*s:%d",
sb->s_id, le32_to_cpu(es->s_first_error_time),
(int) sizeof(es->s_first_error_func),
es->s_first_error_func,
@@ -2606,7 +2607,7 @@ static void print_daily_error_info(unsigned long arg)
printk("\n");
}
if (es->s_last_error_time) {
- printk(KERN_NOTICE "EXT4-fs (%s): last error at %u: %.*s:%d",
+ printk(KERN_NOTICE "EXT4-fs (%s): last error at time %u: %.*s:%d",
sb->s_id, le32_to_cpu(es->s_last_error_time),
(int) sizeof(es->s_last_error_func),
es->s_last_error_func,
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 4b843ace285c..9cb82b9aeb73 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -1152,7 +1152,13 @@ done:
int current_cpuset_is_being_rebound(void)
{
- return task_cs(current) == cpuset_being_rebound;
+ int ret;
+
+ rcu_read_lock();
+ ret = task_cs(current) == cpuset_being_rebound;
+ rcu_read_unlock();
+
+ return ret;
}
static int update_relax_domain_level(struct cpuset *cs, s64 val)
diff --git a/kernel/rtmutex-debug.h b/kernel/rtmutex-debug.h
index 14193d596d78..ab29b6a22669 100644
--- a/kernel/rtmutex-debug.h
+++ b/kernel/rtmutex-debug.h
@@ -31,3 +31,8 @@ static inline int debug_rt_mutex_detect_deadlock(struct rt_mutex_waiter *waiter,
{
return (waiter != NULL);
}
+
+static inline void rt_mutex_print_deadlock(struct rt_mutex_waiter *w)
+{
+ debug_rt_mutex_print_deadlock(w);
+}
diff --git a/kernel/rtmutex.c b/kernel/rtmutex.c
index a242e691c993..375ae48479fa 100644
--- a/kernel/rtmutex.c
+++ b/kernel/rtmutex.c
@@ -81,6 +81,47 @@ static inline void mark_rt_mutex_waiters(struct rt_mutex *lock)
owner = *p;
} while (cmpxchg(p, owner, owner | RT_MUTEX_HAS_WAITERS) != owner);
}
+
+/*
+ * Safe fastpath aware unlock:
+ * 1) Clear the waiters bit
+ * 2) Drop lock->wait_lock
+ * 3) Try to unlock the lock with cmpxchg
+ */
+static inline bool unlock_rt_mutex_safe(struct rt_mutex *lock)
+ __releases(lock->wait_lock)
+{
+ struct task_struct *owner = rt_mutex_owner(lock);
+
+ clear_rt_mutex_waiters(lock);
+ raw_spin_unlock(&lock->wait_lock);
+ /*
+ * If a new waiter comes in between the unlock and the cmpxchg
+ * we have two situations:
+ *
+ * unlock(wait_lock);
+ * lock(wait_lock);
+ * cmpxchg(p, owner, 0) == owner
+ * mark_rt_mutex_waiters(lock);
+ * acquire(lock);
+ * or:
+ *
+ * unlock(wait_lock);
+ * lock(wait_lock);
+ * mark_rt_mutex_waiters(lock);
+ *
+ * cmpxchg(p, owner, 0) != owner
+ * enqueue_waiter();
+ * unlock(wait_lock);
+ * lock(wait_lock);
+ * wake waiter();
+ * unlock(wait_lock);
+ * lock(wait_lock);
+ * acquire(lock);
+ */
+ return rt_mutex_cmpxchg(lock, owner, NULL);
+}
+
#else
# define rt_mutex_cmpxchg(l,c,n) (0)
static inline void mark_rt_mutex_waiters(struct rt_mutex *lock)
@@ -88,6 +129,17 @@ static inline void mark_rt_mutex_waiters(struct rt_mutex *lock)
lock->owner = (struct task_struct *)
((unsigned long)lock->owner | RT_MUTEX_HAS_WAITERS);
}
+
+/*
+ * Simple slow path only version: lock->owner is protected by lock->wait_lock.
+ */
+static inline bool unlock_rt_mutex_safe(struct rt_mutex *lock)
+ __releases(lock->wait_lock)
+{
+ lock->owner = NULL;
+ raw_spin_unlock(&lock->wait_lock);
+ return true;
+}
#endif
/*
@@ -141,6 +193,11 @@ static void rt_mutex_adjust_prio(struct task_struct *task)
*/
int max_lock_depth = 1024;
+static inline struct rt_mutex *task_blocked_on_lock(struct task_struct *p)
+{
+ return p->pi_blocked_on ? p->pi_blocked_on->lock : NULL;
+}
+
/*
* Adjust the priority chain. Also used for deadlock detection.
* Decreases task's usage by one - may thus free the task.
@@ -149,6 +206,7 @@ int max_lock_depth = 1024;
static int rt_mutex_adjust_prio_chain(struct task_struct *task,
int deadlock_detect,
struct rt_mutex *orig_lock,
+ struct rt_mutex *next_lock,
struct rt_mutex_waiter *orig_waiter,
struct task_struct *top_task)
{
@@ -182,7 +240,7 @@ static int rt_mutex_adjust_prio_chain(struct task_struct *task,
}
put_task_struct(task);
- return deadlock_detect ? -EDEADLK : 0;
+ return -EDEADLK;
}
retry:
/*
@@ -207,13 +265,32 @@ static int rt_mutex_adjust_prio_chain(struct task_struct *task,
goto out_unlock_pi;
/*
+ * We dropped all locks after taking a refcount on @task, so
+ * the task might have moved on in the lock chain or even left
+ * the chain completely and blocks now on an unrelated lock or
+ * on @orig_lock.
+ *
+ * We stored the lock on which @task was blocked in @next_lock,
+ * so we can detect the chain change.
+ */
+ if (next_lock != waiter->lock)
+ goto out_unlock_pi;
+
+ /*
* Drop out, when the task has no waiters. Note,
* top_waiter can be NULL, when we are in the deboosting
* mode!
*/
- if (top_waiter && (!task_has_pi_waiters(task) ||
- top_waiter != task_top_pi_waiter(task)))
- goto out_unlock_pi;
+ if (top_waiter) {
+ if (!task_has_pi_waiters(task))
+ goto out_unlock_pi;
+ /*
+ * If deadlock detection is off, we stop here if we
+ * are not the top pi waiter of the task.
+ */
+ if (!detect_deadlock && top_waiter != task_top_pi_waiter(task))
+ goto out_unlock_pi;
+ }
/*
* When deadlock detection is off then we check, if further
@@ -229,11 +306,16 @@ static int rt_mutex_adjust_prio_chain(struct task_struct *task,
goto retry;
}
- /* Deadlock detection */
+ /*
+ * Deadlock detection. If the lock is the same as the original
+ * lock which caused us to walk the lock chain or if the
+ * current lock is owned by the task which initiated the chain
+ * walk, we detected a deadlock.
+ */
if (lock == orig_lock || rt_mutex_owner(lock) == top_task) {
debug_rt_mutex_deadlock(deadlock_detect, orig_waiter, lock);
raw_spin_unlock(&lock->wait_lock);
- ret = deadlock_detect ? -EDEADLK : 0;
+ ret = -EDEADLK;
goto out_unlock_pi;
}
@@ -280,11 +362,26 @@ static int rt_mutex_adjust_prio_chain(struct task_struct *task,
__rt_mutex_adjust_prio(task);
}
+ /*
+ * Check whether the task which owns the current lock is pi
+ * blocked itself. If yes we store a pointer to the lock for
+ * the lock chain change detection above. After we dropped
+ * task->pi_lock next_lock cannot be dereferenced anymore.
+ */
+ next_lock = task_blocked_on_lock(task);
+
raw_spin_unlock_irqrestore(&task->pi_lock, flags);
top_waiter = rt_mutex_top_waiter(lock);
raw_spin_unlock(&lock->wait_lock);
+ /*
+ * We reached the end of the lock chain. Stop right here. No
+ * point to go back just to figure that out.
+ */
+ if (!next_lock)
+ goto out_put_task;
+
if (!detect_deadlock && waiter != top_waiter)
goto out_put_task;
@@ -395,8 +492,21 @@ static int task_blocks_on_rt_mutex(struct rt_mutex *lock,
{
struct task_struct *owner = rt_mutex_owner(lock);
struct rt_mutex_waiter *top_waiter = waiter;
- unsigned long flags;
+ struct rt_mutex *next_lock;
int chain_walk = 0, res;
+ unsigned long flags;
+
+ /*
+ * Early deadlock detection. We really don't want the task to
+ * enqueue on itself just to untangle the mess later. It's not
+ * only an optimization. We drop the locks, so another waiter
+ * can come in before the chain walk detects the deadlock. So
+ * the other will detect the deadlock and return -EDEADLOCK,
+ * which is wrong, as the other waiter is not in a deadlock
+ * situation.
+ */
+ if (owner == task)
+ return -EDEADLK;
raw_spin_lock_irqsave(&task->pi_lock, flags);
__rt_mutex_adjust_prio(task);
@@ -417,20 +527,28 @@ static int task_blocks_on_rt_mutex(struct rt_mutex *lock,
if (!owner)
return 0;
+ raw_spin_lock_irqsave(&owner->pi_lock, flags);
if (waiter == rt_mutex_top_waiter(lock)) {
- raw_spin_lock_irqsave(&owner->pi_lock, flags);
plist_del(&top_waiter->pi_list_entry, &owner->pi_waiters);
plist_add(&waiter->pi_list_entry, &owner->pi_waiters);
__rt_mutex_adjust_prio(owner);
if (owner->pi_blocked_on)
chain_walk = 1;
- raw_spin_unlock_irqrestore(&owner->pi_lock, flags);
- }
- else if (debug_rt_mutex_detect_deadlock(waiter, detect_deadlock))
+ } else if (debug_rt_mutex_detect_deadlock(waiter, detect_deadlock)) {
chain_walk = 1;
+ }
+
+ /* Store the lock on which owner is blocked or NULL */
+ next_lock = task_blocked_on_lock(owner);
- if (!chain_walk)
+ raw_spin_unlock_irqrestore(&owner->pi_lock, flags);
+ /*
+ * Even if full deadlock detection is on, if the owner is not
+ * blocked itself, we can avoid finding this out in the chain
+ * walk.
+ */
+ if (!chain_walk || !next_lock)
return 0;
/*
@@ -442,8 +560,8 @@ static int task_blocks_on_rt_mutex(struct rt_mutex *lock,
raw_spin_unlock(&lock->wait_lock);
- res = rt_mutex_adjust_prio_chain(owner, detect_deadlock, lock, waiter,
- task);
+ res = rt_mutex_adjust_prio_chain(owner, detect_deadlock, lock,
+ next_lock, waiter, task);
raw_spin_lock(&lock->wait_lock);
@@ -453,7 +571,8 @@ static int task_blocks_on_rt_mutex(struct rt_mutex *lock,
/*
* Wake up the next waiter on the lock.
*
- * Remove the top waiter from the current tasks waiter list and wake it up.
+ * Remove the top waiter from the current tasks pi waiter list and
+ * wake it up.
*
* Called with lock->wait_lock held.
*/
@@ -474,10 +593,23 @@ static void wakeup_next_waiter(struct rt_mutex *lock)
*/
plist_del(&waiter->pi_list_entry, ¤t->pi_waiters);
- rt_mutex_set_owner(lock, NULL);
+ /*
+ * As we are waking up the top waiter, and the waiter stays
+ * queued on the lock until it gets the lock, this lock
+ * obviously has waiters. Just set the bit here and this has
+ * the added benefit of forcing all new tasks into the
+ * slow path making sure no task of lower priority than
+ * the top waiter can steal this lock.
+ */
+ lock->owner = (void *) RT_MUTEX_HAS_WAITERS;
raw_spin_unlock_irqrestore(¤t->pi_lock, flags);
+ /*
+ * It's safe to dereference waiter as it cannot go away as
+ * long as we hold lock->wait_lock. The waiter task needs to
+ * acquire it in order to dequeue the waiter.
+ */
wake_up_process(waiter->task);
}
@@ -492,8 +624,8 @@ static void remove_waiter(struct rt_mutex *lock,
{
int first = (waiter == rt_mutex_top_waiter(lock));
struct task_struct *owner = rt_mutex_owner(lock);
+ struct rt_mutex *next_lock = NULL;
unsigned long flags;
- int chain_walk = 0;
raw_spin_lock_irqsave(¤t->pi_lock, flags);
plist_del(&waiter->list_entry, &lock->wait_list);
@@ -517,15 +649,15 @@ static void remove_waiter(struct rt_mutex *lock,
}
__rt_mutex_adjust_prio(owner);
- if (owner->pi_blocked_on)
- chain_walk = 1;
+ /* Store the lock on which owner is blocked or NULL */
+ next_lock = task_blocked_on_lock(owner);
raw_spin_unlock_irqrestore(&owner->pi_lock, flags);
}
WARN_ON(!plist_node_empty(&waiter->pi_list_entry));
- if (!chain_walk)
+ if (!next_lock)
return;
/* gets dropped in rt_mutex_adjust_prio_chain()! */
@@ -533,7 +665,7 @@ static void remove_waiter(struct rt_mutex *lock,
raw_spin_unlock(&lock->wait_lock);
- rt_mutex_adjust_prio_chain(owner, 0, lock, NULL, current);
+ rt_mutex_adjust_prio_chain(owner, 0, lock, next_lock, NULL, current);
raw_spin_lock(&lock->wait_lock);
}
@@ -546,6 +678,7 @@ static void remove_waiter(struct rt_mutex *lock,
void rt_mutex_adjust_pi(struct task_struct *task)
{
struct rt_mutex_waiter *waiter;
+ struct rt_mutex *next_lock;
unsigned long flags;
raw_spin_lock_irqsave(&task->pi_lock, flags);
@@ -555,12 +688,13 @@ void rt_mutex_adjust_pi(struct task_struct *task)
raw_spin_unlock_irqrestore(&task->pi_lock, flags);
return;
}
-
+ next_lock = waiter->lock;
raw_spin_unlock_irqrestore(&task->pi_lock, flags);
/* gets dropped in rt_mutex_adjust_prio_chain()! */
get_task_struct(task);
- rt_mutex_adjust_prio_chain(task, 0, NULL, NULL, task);
+
+ rt_mutex_adjust_prio_chain(task, 0, NULL, next_lock, NULL, task);
}
/**
@@ -612,6 +746,26 @@ __rt_mutex_slowlock(struct rt_mutex *lock, int state,
return ret;
}
+static void rt_mutex_handle_deadlock(int res, int detect_deadlock,
+ struct rt_mutex_waiter *w)
+{
+ /*
+ * If the result is not -EDEADLOCK or the caller requested
+ * deadlock detection, nothing to do here.
+ */
+ if (res != -EDEADLOCK || detect_deadlock)
+ return;
+
+ /*
+ * Yell lowdly and stop the task right here.
+ */
+ rt_mutex_print_deadlock(w);
+ while (1) {
+ set_current_state(TASK_INTERRUPTIBLE);
+ schedule();
+ }
+}
+
/*
* Slow path lock function:
*/
@@ -649,8 +803,10 @@ rt_mutex_slowlock(struct rt_mutex *lock, int state,
set_current_state(TASK_RUNNING);
- if (unlikely(ret))
+ if (unlikely(ret)) {
remove_waiter(lock, &waiter);
+ rt_mutex_handle_deadlock(ret, detect_deadlock, &waiter);
+ }
/*
* try_to_take_rt_mutex() sets the waiter bit
@@ -706,12 +862,49 @@ rt_mutex_slowunlock(struct rt_mutex *lock)
rt_mutex_deadlock_account_unlock(current);
- if (!rt_mutex_has_waiters(lock)) {
- lock->owner = NULL;
- raw_spin_unlock(&lock->wait_lock);
- return;
+ /*
+ * We must be careful here if the fast path is enabled. If we
+ * have no waiters queued we cannot set owner to NULL here
+ * because of:
+ *
+ * foo->lock->owner = NULL;
+ * rtmutex_lock(foo->lock); <- fast path
+ * free = atomic_dec_and_test(foo->refcnt);
+ * rtmutex_unlock(foo->lock); <- fast path
+ * if (free)
+ * kfree(foo);
+ * raw_spin_unlock(foo->lock->wait_lock);
+ *
+ * So for the fastpath enabled kernel:
+ *
+ * Nothing can set the waiters bit as long as we hold
+ * lock->wait_lock. So we do the following sequence:
+ *
+ * owner = rt_mutex_owner(lock);
+ * clear_rt_mutex_waiters(lock);
+ * raw_spin_unlock(&lock->wait_lock);
+ * if (cmpxchg(&lock->owner, owner, 0) == owner)
+ * return;
+ * goto retry;
+ *
+ * The fastpath disabled variant is simple as all access to
+ * lock->owner is serialized by lock->wait_lock:
+ *
+ * lock->owner = NULL;
+ * raw_spin_unlock(&lock->wait_lock);
+ */
+ while (!rt_mutex_has_waiters(lock)) {
+ /* Drops lock->wait_lock ! */
+ if (unlock_rt_mutex_safe(lock) == true)
+ return;
+ /* Relock the rtmutex and try again */
+ raw_spin_lock(&lock->wait_lock);
}
+ /*
+ * The wakeup next waiter path does not suffer from the above
+ * race. See the comments there.
+ */
wakeup_next_waiter(lock);
raw_spin_unlock(&lock->wait_lock);
@@ -958,7 +1151,8 @@ int rt_mutex_start_proxy_lock(struct rt_mutex *lock,
return 1;
}
- ret = task_blocks_on_rt_mutex(lock, waiter, task, detect_deadlock);
+ /* We enforce deadlock detection for futexes */
+ ret = task_blocks_on_rt_mutex(lock, waiter, task, 1);
if (ret && !rt_mutex_owner(lock)) {
/*
diff --git a/kernel/rtmutex.h b/kernel/rtmutex.h
index a1a1dd06421d..f6a1f3c133b1 100644
--- a/kernel/rtmutex.h
+++ b/kernel/rtmutex.h
@@ -24,3 +24,8 @@
#define debug_rt_mutex_print_deadlock(w) do { } while (0)
#define debug_rt_mutex_detect_deadlock(w,d) (d)
#define debug_rt_mutex_reset_waiter(w) do { } while (0)
+
+static inline void rt_mutex_print_deadlock(struct rt_mutex_waiter *w)
+{
+ WARN(1, "rtmutex deadlock detected\n");
+}
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index a494ec317e0a..8897a6f5c408 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1052,7 +1052,6 @@ void tracing_start(void)
arch_spin_unlock(&ftrace_max_lock);
- ftrace_start();
out:
raw_spin_unlock_irqrestore(&tracing_start_lock, flags);
}
@@ -1068,7 +1067,6 @@ void tracing_stop(void)
struct ring_buffer *buffer;
unsigned long flags;
- ftrace_stop();
raw_spin_lock_irqsave(&tracing_start_lock, flags);
if (trace_stop_count++)
goto out;
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index ee50c256fdc3..5cec36b6e838 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1991,7 +1991,6 @@ struct mempolicy *__mpol_dup(struct mempolicy *old)
} else
*new = *old;
- rcu_read_lock();
if (current_cpuset_is_being_rebound()) {
nodemask_t mems = cpuset_mems_allowed(current);
if (new->flags & MPOL_F_REBINDING)
@@ -1999,7 +1998,6 @@ struct mempolicy *__mpol_dup(struct mempolicy *old)
else
mpol_rebind_policy(new, &mems, MPOL_REBIND_ONCE);
}
- rcu_read_unlock();
atomic_set(&new->refcnt, 1);
return new;
}
^ permalink raw reply [flat|nested] 2+ messages in thread