Re: Linux 3.4.52

From: Greg KH
Date: Wed Jul 03 2013 - 14:17:16 EST

diff --git a/Makefile b/Makefile
index 5adfadf..810572b 100644
--- a/Makefile
+++ b/Makefile
@@ -1,6 +1,6 @@
VERSION = 3
PATCHLEVEL = 4
-SUBLEVEL = 51
+SUBLEVEL = 52
EXTRAVERSION =
NAME = Saber-toothed Squirrel

diff --git a/arch/arm/include/asm/cacheflush.h b/arch/arm/include/asm/cacheflush.h
index 42dec04..0a5e8a5 100644
--- a/arch/arm/include/asm/cacheflush.h
+++ b/arch/arm/include/asm/cacheflush.h
@@ -305,9 +305,7 @@ static inline void flush_anon_page(struct vm_area_struct *vma,
}

#define ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE
-static inline void flush_kernel_dcache_page(struct page *page)
-{
-}
+extern void flush_kernel_dcache_page(struct page *);

#define flush_dcache_mmap_lock(mapping) \
spin_lock_irq(&(mapping)->tree_lock)
diff --git a/arch/arm/mm/flush.c b/arch/arm/mm/flush.c
index 40ca11e..8f0d285 100644
--- a/arch/arm/mm/flush.c
+++ b/arch/arm/mm/flush.c
@@ -299,6 +299,39 @@ void flush_dcache_page(struct page *page)
EXPORT_SYMBOL(flush_dcache_page);

/*
+ * Ensure cache coherency for the kernel mapping of this page. We can
+ * assume that the page is pinned via kmap.
+ *
+ * If the page only exists in the page cache and there are no user
+ * space mappings, this is a no-op since the page was already marked
+ * dirty at creation. Otherwise, we need to flush the dirty kernel
+ * cache lines directly.
+ */
+void flush_kernel_dcache_page(struct page *page)
+{
+ if (cache_is_vivt() || cache_is_vipt_aliasing()) {
+ struct address_space *mapping;
+
+ mapping = page_mapping(page);
+
+ if (!mapping || mapping_mapped(mapping)) {
+ void *addr;
+
+ addr = page_address(page);
+ /*
+ * kmap_atomic() doesn't set the page virtual
+ * address for highmem pages, and
+ * kunmap_atomic() takes care of cache
+ * flushing already.
+ */
+ if (!IS_ENABLED(CONFIG_HIGHMEM) || addr)
+ __cpuc_flush_dcache_area(addr, PAGE_SIZE);
+ }
+ }
+}
+EXPORT_SYMBOL(flush_kernel_dcache_page);
+
+/*
* Flush an anonymous page so that users of get_user_pages()
* can safely access the data. The expected sequence is:
*
diff --git a/arch/arm/mm/nommu.c b/arch/arm/mm/nommu.c
index d51225f..eb5293a 100644
--- a/arch/arm/mm/nommu.c
+++ b/arch/arm/mm/nommu.c
@@ -57,6 +57,12 @@ void flush_dcache_page(struct page *page)
}
EXPORT_SYMBOL(flush_dcache_page);

+void flush_kernel_dcache_page(struct page *page)
+{
+ __cpuc_flush_dcache_area(page_address(page), PAGE_SIZE);
+}
+EXPORT_SYMBOL(flush_kernel_dcache_page);
+
void copy_to_user_page(struct vm_area_struct *vma, struct page *page,
unsigned long uaddr, void *dst, const void *src,
unsigned long len)
diff --git a/drivers/net/wan/dlci.c b/drivers/net/wan/dlci.c
index 147614e..6a8a382 100644
--- a/drivers/net/wan/dlci.c
+++ b/drivers/net/wan/dlci.c
@@ -384,21 +384,37 @@ static int dlci_del(struct dlci_add *dlci)
struct frad_local *flp;
struct net_device *master, *slave;
int err;
+ bool found = false;
+
+ rtnl_lock();

/* validate slave device */
master = __dev_get_by_name(&init_net, dlci->devname);
- if (!master)
- return -ENODEV;
+ if (!master) {
+ err = -ENODEV;
+ goto out;
+ }
+
+ list_for_each_entry(dlp, &dlci_devs, list) {
+ if (dlp->master == master) {
+ found = true;
+ break;
+ }
+ }
+ if (!found) {
+ err = -ENODEV;
+ goto out;
+ }

if (netif_running(master)) {
- return -EBUSY;
+ err = -EBUSY;
+ goto out;
}

dlp = netdev_priv(master);
slave = dlp->slave;
flp = netdev_priv(slave);

- rtnl_lock();
err = (*flp->deassoc)(slave, master);
if (!err) {
list_del(&dlp->list);
@@ -407,8 +423,8 @@ static int dlci_del(struct dlci_add *dlci)

dev_put(slave);
}
+out:
rtnl_unlock();
-
return err;
}

diff --git a/drivers/tty/serial/pch_uart.c b/drivers/tty/serial/pch_uart.c
index 7d47514..2e99f79 100644
--- a/drivers/tty/serial/pch_uart.c
+++ b/drivers/tty/serial/pch_uart.c
@@ -1034,22 +1034,37 @@ static unsigned int dma_handle_tx(struct eg20t_port *priv)
static void pch_uart_err_ir(struct eg20t_port *priv, unsigned int lsr)
{
u8 fcr = ioread8(priv->membase + UART_FCR);
+ struct uart_port *port = &priv->port;
+ struct tty_struct *tty = tty_port_tty_get(&port->state->port);
+ char *error_msg[5] = {};
+ int i = 0;

/* Reset FIFO */
fcr |= UART_FCR_CLEAR_RCVR;
iowrite8(fcr, priv->membase + UART_FCR);

if (lsr & PCH_UART_LSR_ERR)
- dev_err(&priv->pdev->dev, "Error data in FIFO\n");
+ error_msg[i++] = "Error data in FIFO\n";

- if (lsr & UART_LSR_FE)
- dev_err(&priv->pdev->dev, "Framing Error\n");
+ if (lsr & UART_LSR_FE) {
+ port->icount.frame++;
+ error_msg[i++] = " Framing Error\n";
+ }

- if (lsr & UART_LSR_PE)
- dev_err(&priv->pdev->dev, "Parity Error\n");
+ if (lsr & UART_LSR_PE) {
+ port->icount.parity++;
+ error_msg[i++] = " Parity Error\n";
+ }

- if (lsr & UART_LSR_OE)
- dev_err(&priv->pdev->dev, "Overrun Error\n");
+ if (lsr & UART_LSR_OE) {
+ port->icount.overrun++;
+ error_msg[i++] = " Overrun Error\n";
+ }
+
+ if (tty == NULL) {
+ for (i = 0; error_msg[i] != NULL; i++)
+ dev_err(&priv->pdev->dev, error_msg[i]);
+ }
}

static irqreturn_t pch_uart_interrupt(int irq, void *dev_id)
diff --git a/fs/exec.c b/fs/exec.c
index 2b7f5ff..0ea0b4c 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1163,13 +1163,6 @@ void setup_new_exec(struct linux_binprm * bprm)
set_dumpable(current->mm, suid_dumpable);
}

- /*
- * Flush performance counters when crossing a
- * security domain:
- */
- if (!get_dumpable(current->mm))
- perf_event_exit_task(current);
-
/* An exec changes our domain. We are no longer part of the thread
group */

@@ -1233,6 +1226,15 @@ void install_exec_creds(struct linux_binprm *bprm)

commit_creds(bprm->cred);
bprm->cred = NULL;
+
+ /*
+ * Disable monitoring for regular users
+ * when executing setuid binaries. Must
+ * wait until new credentials are committed
+ * by commit_creds() above
+ */
+ if (get_dumpable(current->mm) != SUID_DUMP_USER)
+ perf_event_exit_task(current);
/*
* cred_guard_mutex must be held at least to this point to prevent
* ptrace_attach() from altering our determination of the task's
diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c
index 8640a12..25c472b 100644
--- a/fs/ubifs/dir.c
+++ b/fs/ubifs/dir.c
@@ -357,31 +357,50 @@ static unsigned int vfs_dent_type(uint8_t type)
static int ubifs_readdir(struct file *file, void *dirent, filldir_t filldir)
{
int err, over = 0;
+ loff_t pos = file->f_pos;
struct qstr nm;
union ubifs_key key;
struct ubifs_dent_node *dent;
struct inode *dir = file->f_path.dentry->d_inode;
struct ubifs_info *c = dir->i_sb->s_fs_info;

- dbg_gen("dir ino %lu, f_pos %#llx", dir->i_ino, file->f_pos);
+ dbg_gen("dir ino %lu, f_pos %#llx", dir->i_ino, pos);

- if (file->f_pos > UBIFS_S_KEY_HASH_MASK || file->f_pos == 2)
+ if (pos > UBIFS_S_KEY_HASH_MASK || pos == 2)
/*
* The directory was seek'ed to a senseless position or there
* are no more entries.
*/
return 0;

+ if (file->f_version == 0) {
+ /*
+ * The file was seek'ed, which means that @file->private_data
+ * is now invalid. This may also be just the first
+ * 'ubifs_readdir()' invocation, in which case
+ * @file->private_data is NULL, and the below code is
+ * basically a no-op.
+ */
+ kfree(file->private_data);
+ file->private_data = NULL;
+ }
+
+ /*
+ * 'generic_file_llseek()' unconditionally sets @file->f_version to
+ * zero, and we use this for detecting whether the file was seek'ed.
+ */
+ file->f_version = 1;
+
/* File positions 0 and 1 correspond to "." and ".." */
- if (file->f_pos == 0) {
+ if (pos == 0) {
ubifs_assert(!file->private_data);
over = filldir(dirent, ".", 1, 0, dir->i_ino, DT_DIR);
if (over)
return 0;
- file->f_pos = 1;
+ file->f_pos = pos = 1;
}

- if (file->f_pos == 1) {
+ if (pos == 1) {
ubifs_assert(!file->private_data);
over = filldir(dirent, "..", 2, 1,
parent_ino(file->f_path.dentry), DT_DIR);
@@ -397,7 +416,7 @@ static int ubifs_readdir(struct file *file, void *dirent, filldir_t filldir)
goto out;
}

- file->f_pos = key_hash_flash(c, &dent->key);
+ file->f_pos = pos = key_hash_flash(c, &dent->key);
file->private_data = dent;
}

@@ -405,17 +424,16 @@ static int ubifs_readdir(struct file *file, void *dirent, filldir_t filldir)
if (!dent) {
/*
* The directory was seek'ed to and is now readdir'ed.
- * Find the entry corresponding to @file->f_pos or the
- * closest one.
+ * Find the entry corresponding to @pos or the closest one.
*/
- dent_key_init_hash(c, &key, dir->i_ino, file->f_pos);
+ dent_key_init_hash(c, &key, dir->i_ino, pos);
nm.name = NULL;
dent = ubifs_tnc_next_ent(c, &key, &nm);
if (IS_ERR(dent)) {
err = PTR_ERR(dent);
goto out;
}
- file->f_pos = key_hash_flash(c, &dent->key);
+ file->f_pos = pos = key_hash_flash(c, &dent->key);
file->private_data = dent;
}

@@ -427,7 +445,7 @@ static int ubifs_readdir(struct file *file, void *dirent, filldir_t filldir)
ubifs_inode(dir)->creat_sqnum);

nm.len = le16_to_cpu(dent->nlen);
- over = filldir(dirent, dent->name, nm.len, file->f_pos,
+ over = filldir(dirent, dent->name, nm.len, pos,
le64_to_cpu(dent->inum),
vfs_dent_type(dent->type));
if (over)
@@ -443,9 +461,17 @@ static int ubifs_readdir(struct file *file, void *dirent, filldir_t filldir)
}

kfree(file->private_data);
- file->f_pos = key_hash_flash(c, &dent->key);
+ file->f_pos = pos = key_hash_flash(c, &dent->key);
file->private_data = dent;
cond_resched();
+
+ if (file->f_version == 0)
+ /*
+ * The file was seek'ed meanwhile, lets return and start
+ * reading direntries from the new position on the next
+ * invocation.
+ */
+ return 0;
}

out:
@@ -456,15 +482,13 @@ out:

kfree(file->private_data);
file->private_data = NULL;
+ /* 2 is a special value indicating that there are no more direntries */
file->f_pos = 2;
return 0;
}

-/* If a directory is seeked, we have to free saved readdir() state */
static loff_t ubifs_dir_llseek(struct file *file, loff_t offset, int origin)
{
- kfree(file->private_data);
- file->private_data = NULL;
return generic_file_llseek(file, offset, origin);
}

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 8e9a069..89fb74e 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -950,8 +950,7 @@ struct perf_event {
/* mmap bits */
struct mutex mmap_mutex;
atomic_t mmap_count;
- int mmap_locked;
- struct user_struct *mmap_user;
+
struct ring_buffer *rb;
struct list_head rb_entry;

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 839a24f..7ceb270 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -193,9 +193,6 @@ static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
static void update_context_time(struct perf_event_context *ctx);
static u64 perf_event_time(struct perf_event *event);

-static void ring_buffer_attach(struct perf_event *event,
- struct ring_buffer *rb);
-
void __weak perf_event_print_debug(void) { }

extern __weak const char *perf_pmu_name(void)
@@ -2849,6 +2846,7 @@ static void free_event_rcu(struct rcu_head *head)
}

static void ring_buffer_put(struct ring_buffer *rb);
+static void ring_buffer_detach(struct perf_event *event, struct ring_buffer *rb);

static void free_event(struct perf_event *event)
{
@@ -2873,15 +2871,30 @@ static void free_event(struct perf_event *event)
if (has_branch_stack(event)) {
static_key_slow_dec_deferred(&perf_sched_events);
/* is system-wide event */
- if (!(event->attach_state & PERF_ATTACH_TASK))
+ if (!(event->attach_state & PERF_ATTACH_TASK)) {
atomic_dec(&per_cpu(perf_branch_stack_events,
event->cpu));
+ }
}
}

if (event->rb) {
- ring_buffer_put(event->rb);
- event->rb = NULL;
+ struct ring_buffer *rb;
+
+ /*
+ * Can happen when we close an event with re-directed output.
+ *
+ * Since we have a 0 refcount, perf_mmap_close() will skip
+ * over us; possibly making our ring_buffer_put() the last.
+ */
+ mutex_lock(&event->mmap_mutex);
+ rb = event->rb;
+ if (rb) {
+ rcu_assign_pointer(event->rb, NULL);
+ ring_buffer_detach(event, rb);
+ ring_buffer_put(rb); /* could be last */
+ }
+ mutex_unlock(&event->mmap_mutex);
}

if (is_cgroup_event(event))
@@ -3119,30 +3132,13 @@ static unsigned int perf_poll(struct file *file, poll_table *wait)
unsigned int events = POLL_HUP;

/*
- * Race between perf_event_set_output() and perf_poll(): perf_poll()
- * grabs the rb reference but perf_event_set_output() overrides it.
- * Here is the timeline for two threads T1, T2:
- * t0: T1, rb = rcu_dereference(event->rb)
- * t1: T2, old_rb = event->rb
- * t2: T2, event->rb = new rb
- * t3: T2, ring_buffer_detach(old_rb)
- * t4: T1, ring_buffer_attach(rb1)
- * t5: T1, poll_wait(event->waitq)
- *
- * To avoid this problem, we grab mmap_mutex in perf_poll()
- * thereby ensuring that the assignment of the new ring buffer
- * and the detachment of the old buffer appear atomic to perf_poll()
+ * Pin the event->rb by taking event->mmap_mutex; otherwise
+ * perf_event_set_output() can swizzle our rb and make us miss wakeups.
*/
mutex_lock(&event->mmap_mutex);
-
- rcu_read_lock();
- rb = rcu_dereference(event->rb);
- if (rb) {
- ring_buffer_attach(event, rb);
+ rb = event->rb;
+ if (rb)
events = atomic_xchg(&rb->poll, 0);
- }
- rcu_read_unlock();
-
mutex_unlock(&event->mmap_mutex);

poll_wait(file, &event->waitq, wait);
@@ -3459,16 +3455,12 @@ static void ring_buffer_attach(struct perf_event *event,
return;

spin_lock_irqsave(&rb->event_lock, flags);
- if (!list_empty(&event->rb_entry))
- goto unlock;
-
- list_add(&event->rb_entry, &rb->event_list);
-unlock:
+ if (list_empty(&event->rb_entry))
+ list_add(&event->rb_entry, &rb->event_list);
spin_unlock_irqrestore(&rb->event_lock, flags);
}

-static void ring_buffer_detach(struct perf_event *event,
- struct ring_buffer *rb)
+static void ring_buffer_detach(struct perf_event *event, struct ring_buffer *rb)
{
unsigned long flags;

@@ -3487,13 +3479,10 @@ static void ring_buffer_wakeup(struct perf_event *event)

rcu_read_lock();
rb = rcu_dereference(event->rb);
- if (!rb)
- goto unlock;
-
- list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
- wake_up_all(&event->waitq);
-
-unlock:
+ if (rb) {
+ list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
+ wake_up_all(&event->waitq);
+ }
rcu_read_unlock();
}

@@ -3522,18 +3511,10 @@ static struct ring_buffer *ring_buffer_get(struct perf_event *event)

static void ring_buffer_put(struct ring_buffer *rb)
{
- struct perf_event *event, *n;
- unsigned long flags;
-
if (!atomic_dec_and_test(&rb->refcount))
return;

- spin_lock_irqsave(&rb->event_lock, flags);
- list_for_each_entry_safe(event, n, &rb->event_list, rb_entry) {
- list_del_init(&event->rb_entry);
- wake_up_all(&event->waitq);
- }
- spin_unlock_irqrestore(&rb->event_lock, flags);
+ WARN_ON_ONCE(!list_empty(&rb->event_list));

call_rcu(&rb->rcu_head, rb_free_rcu);
}
@@ -3543,26 +3524,100 @@ static void perf_mmap_open(struct vm_area_struct *vma)
struct perf_event *event = vma->vm_file->private_data;

atomic_inc(&event->mmap_count);
+ atomic_inc(&event->rb->mmap_count);
}

+/*
+ * A buffer can be mmap()ed multiple times; either directly through the same
+ * event, or through other events by use of perf_event_set_output().
+ *
+ * In order to undo the VM accounting done by perf_mmap() we need to destroy
+ * the buffer here, where we still have a VM context. This means we need
+ * to detach all events redirecting to us.
+ */
static void perf_mmap_close(struct vm_area_struct *vma)
{
struct perf_event *event = vma->vm_file->private_data;

- if (atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex)) {
- unsigned long size = perf_data_size(event->rb);
- struct user_struct *user = event->mmap_user;
- struct ring_buffer *rb = event->rb;
+ struct ring_buffer *rb = event->rb;
+ struct user_struct *mmap_user = rb->mmap_user;
+ int mmap_locked = rb->mmap_locked;
+ unsigned long size = perf_data_size(rb);
+
+ atomic_dec(&rb->mmap_count);
+
+ if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
+ return;
+
+ /* Detach current event from the buffer. */
+ rcu_assign_pointer(event->rb, NULL);
+ ring_buffer_detach(event, rb);
+ mutex_unlock(&event->mmap_mutex);
+
+ /* If there's still other mmap()s of this buffer, we're done. */
+ if (atomic_read(&rb->mmap_count)) {
+ ring_buffer_put(rb); /* can't be last */
+ return;
+ }
+
+ /*
+ * No other mmap()s, detach from all other events that might redirect
+ * into the now unreachable buffer. Somewhat complicated by the
+ * fact that rb::event_lock otherwise nests inside mmap_mutex.
+ */
+again:
+ rcu_read_lock();
+ list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
+ if (!atomic_long_inc_not_zero(&event->refcount)) {
+ /*
+ * This event is en-route to free_event() which will
+ * detach it and remove it from the list.
+ */
+ continue;
+ }
+ rcu_read_unlock();

- atomic_long_sub((size >> PAGE_SHIFT) + 1, &user->locked_vm);
- vma->vm_mm->pinned_vm -= event->mmap_locked;
- rcu_assign_pointer(event->rb, NULL);
- ring_buffer_detach(event, rb);
+ mutex_lock(&event->mmap_mutex);
+ /*
+ * Check we didn't race with perf_event_set_output() which can
+ * swizzle the rb from under us while we were waiting to
+ * acquire mmap_mutex.
+ *
+ * If we find a different rb; ignore this event, a next
+ * iteration will no longer find it on the list. We have to
+ * still restart the iteration to make sure we're not now
+ * iterating the wrong list.
+ */
+ if (event->rb == rb) {
+ rcu_assign_pointer(event->rb, NULL);
+ ring_buffer_detach(event, rb);
+ ring_buffer_put(rb); /* can't be last, we still have one */
+ }
mutex_unlock(&event->mmap_mutex);
+ put_event(event);

- ring_buffer_put(rb);
- free_uid(user);
+ /*
+ * Restart the iteration; either we're on the wrong list or
+ * destroyed its integrity by doing a deletion.
+ */
+ goto again;
}
+ rcu_read_unlock();
+
+ /*
+ * It could be there's still a few 0-ref events on the list; they'll
+ * get cleaned up by free_event() -- they'll also still have their
+ * ref on the rb and will free it whenever they are done with it.
+ *
+ * Aside from that, this buffer is 'fully' detached and unmapped,
+ * undo the VM accounting.
+ */
+
+ atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
+ vma->vm_mm->pinned_vm -= mmap_locked;
+ free_uid(mmap_user);
+
+ ring_buffer_put(rb); /* could be last */
}

static const struct vm_operations_struct perf_mmap_vmops = {
@@ -3612,12 +3667,24 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma)
return -EINVAL;

WARN_ON_ONCE(event->ctx->parent_ctx);
+again:
mutex_lock(&event->mmap_mutex);
if (event->rb) {
- if (event->rb->nr_pages == nr_pages)
- atomic_inc(&event->rb->refcount);
- else
+ if (event->rb->nr_pages != nr_pages) {
ret = -EINVAL;
+ goto unlock;
+ }
+
+ if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
+ /*
+ * Raced against perf_mmap_close() through
+ * perf_event_set_output(). Try again, hope for better
+ * luck.
+ */
+ mutex_unlock(&event->mmap_mutex);
+ goto again;
+ }
+
goto unlock;
}

@@ -3658,12 +3725,16 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma)
ret = -ENOMEM;
goto unlock;
}
- rcu_assign_pointer(event->rb, rb);
+
+ atomic_set(&rb->mmap_count, 1);
+ rb->mmap_locked = extra;
+ rb->mmap_user = get_current_user();

atomic_long_add(user_extra, &user->locked_vm);
- event->mmap_locked = extra;
- event->mmap_user = get_current_user();
- vma->vm_mm->pinned_vm += event->mmap_locked;
+ vma->vm_mm->pinned_vm += extra;
+
+ ring_buffer_attach(event, rb);
+ rcu_assign_pointer(event->rb, rb);

perf_event_update_userpage(event);

@@ -3672,7 +3743,11 @@ unlock:
atomic_inc(&event->mmap_count);
mutex_unlock(&event->mmap_mutex);

- vma->vm_flags |= VM_RESERVED;
+ /*
+ * Since pinned accounting is per vm we cannot allow fork() to copy our
+ * vma.
+ */
+ vma->vm_flags |= VM_DONTCOPY | VM_RESERVED;
vma->vm_ops = &perf_mmap_vmops;

return ret;
@@ -6161,6 +6236,8 @@ set:
if (atomic_read(&event->mmap_count))
goto unlock;

+ old_rb = event->rb;
+
if (output_event) {
/* get the rb we want to redirect to */
rb = ring_buffer_get(output_event);
@@ -6168,16 +6245,28 @@ set:
goto unlock;
}

- old_rb = event->rb;
- rcu_assign_pointer(event->rb, rb);
if (old_rb)
ring_buffer_detach(event, old_rb);
+
+ if (rb)
+ ring_buffer_attach(event, rb);
+
+ rcu_assign_pointer(event->rb, rb);
+
+ if (old_rb) {
+ ring_buffer_put(old_rb);
+ /*
+ * Since we detached before setting the new rb, so that we
+ * could attach the new rb, we could have missed a wakeup.
+ * Provide it now.
+ */
+ wake_up_all(&event->waitq);
+ }
+
ret = 0;
unlock:
mutex_unlock(&event->mmap_mutex);

- if (old_rb)
- ring_buffer_put(old_rb);
out:
return ret;
}
diff --git a/kernel/events/hw_breakpoint.c b/kernel/events/hw_breakpoint.c
index bb38c4d..fc8bfcf 100644
--- a/kernel/events/hw_breakpoint.c
+++ b/kernel/events/hw_breakpoint.c
@@ -147,7 +147,7 @@ fetch_bp_busy_slots(struct bp_busy_slots *slots, struct perf_event *bp,
return;
}

- for_each_online_cpu(cpu) {
+ for_each_possible_cpu(cpu) {
unsigned int nr;

nr = per_cpu(nr_cpu_bp_pinned[type], cpu);
@@ -233,7 +233,7 @@ toggle_bp_slot(struct perf_event *bp, bool enable, enum bp_type_idx type,
if (cpu >= 0) {
toggle_bp_task_slot(bp, cpu, enable, type, weight);
} else {
- for_each_online_cpu(cpu)
+ for_each_possible_cpu(cpu)
toggle_bp_task_slot(bp, cpu, enable, type, weight);
}

diff --git a/kernel/events/internal.h b/kernel/events/internal.h
index b0b107f..b400e64 100644
--- a/kernel/events/internal.h
+++ b/kernel/events/internal.h
@@ -30,6 +30,10 @@ struct ring_buffer {
spinlock_t event_lock;
struct list_head event_list;

+ atomic_t mmap_count;
+ unsigned long mmap_locked;
+ struct user_struct *mmap_user;
+
struct perf_event_mmap_page *user_page;
void *data_pages[0];
};
diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index fa07aed..932420d 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -1880,6 +1880,9 @@ static struct sk_buff *l2cap_build_cmd(struct l2cap_conn *conn,
BT_DBG("conn %p, code 0x%2.2x, ident 0x%2.2x, len %d",
conn, code, ident, dlen);

+ if (conn->mtu < L2CAP_HDR_SIZE + L2CAP_CMD_HDR_SIZE)
+ return NULL;
+
len = L2CAP_HDR_SIZE + L2CAP_CMD_HDR_SIZE + dlen;
count = min_t(unsigned int, conn->mtu, len);

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