summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2014-07-04 05:53:13 +0400
committerLinus Torvalds <torvalds@linux-foundation.org>2014-07-04 05:53:13 +0400
commit3089f54a7928d28645661c2f3d829e3939d60dd3 (patch)
tree5709fd26998109924da0f2e27154413980b201af
parentef34c6ce49cce8b4d4913fa9166729071f48bab1 (diff)
parent4a3a99045177369700c60d074c0e525e8093b0fc (diff)
downloadlinux-3089f54a7928d28645661c2f3d829e3939d60dd3.tar.xz
Merge tag 'driver-core-3.16-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull driver core fixes from Greg KH: "Well, one drivercore fix for kernfs to resolve a reported issue with sysfs files being updated from atomic contexts, and another lz4 bugfix for testing potential buffer overflows" * tag 'driver-core-3.16-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: lz4: add overrun checks to lz4_uncompress_unknownoutputsize() kernfs: kernfs_notify() must be useable from non-sleepable contexts
-rw-r--r--fs/kernfs/file.c69
-rw-r--r--include/linux/kernfs.h1
-rw-r--r--lib/lz4/lz4_decompress.c6
3 files changed, 61 insertions, 15 deletions
diff --git a/fs/kernfs/file.c b/fs/kernfs/file.c
index e3d37f607f97..d895b4b7b661 100644
--- a/fs/kernfs/file.c
+++ b/fs/kernfs/file.c
@@ -39,6 +39,19 @@ struct kernfs_open_node {
struct list_head files; /* goes through kernfs_open_file.list */
};
+/*
+ * kernfs_notify() may be called from any context and bounces notifications
+ * through a work item. To minimize space overhead in kernfs_node, the
+ * pending queue is implemented as a singly linked list of kernfs_nodes.
+ * The list is terminated with the self pointer so that whether a
+ * kernfs_node is on the list or not can be determined by testing the next
+ * pointer for NULL.
+ */
+#define KERNFS_NOTIFY_EOL ((void *)&kernfs_notify_list)
+
+static DEFINE_SPINLOCK(kernfs_notify_lock);
+static struct kernfs_node *kernfs_notify_list = KERNFS_NOTIFY_EOL;
+
static struct kernfs_open_file *kernfs_of(struct file *file)
{
return ((struct seq_file *)file->private_data)->private;
@@ -783,24 +796,25 @@ static unsigned int kernfs_fop_poll(struct file *filp, poll_table *wait)
return DEFAULT_POLLMASK|POLLERR|POLLPRI;
}
-/**
- * kernfs_notify - notify a kernfs file
- * @kn: file to notify
- *
- * Notify @kn such that poll(2) on @kn wakes up.
- */
-void kernfs_notify(struct kernfs_node *kn)
+static void kernfs_notify_workfn(struct work_struct *work)
{
- struct kernfs_root *root = kernfs_root(kn);
+ struct kernfs_node *kn;
struct kernfs_open_node *on;
struct kernfs_super_info *info;
- unsigned long flags;
-
- if (WARN_ON(kernfs_type(kn) != KERNFS_FILE))
+repeat:
+ /* pop one off the notify_list */
+ spin_lock_irq(&kernfs_notify_lock);
+ kn = kernfs_notify_list;
+ if (kn == KERNFS_NOTIFY_EOL) {
+ spin_unlock_irq(&kernfs_notify_lock);
return;
+ }
+ kernfs_notify_list = kn->attr.notify_next;
+ kn->attr.notify_next = NULL;
+ spin_unlock_irq(&kernfs_notify_lock);
/* kick poll */
- spin_lock_irqsave(&kernfs_open_node_lock, flags);
+ spin_lock_irq(&kernfs_open_node_lock);
on = kn->attr.open;
if (on) {
@@ -808,12 +822,12 @@ void kernfs_notify(struct kernfs_node *kn)
wake_up_interruptible(&on->poll);
}
- spin_unlock_irqrestore(&kernfs_open_node_lock, flags);
+ spin_unlock_irq(&kernfs_open_node_lock);
/* kick fsnotify */
mutex_lock(&kernfs_mutex);
- list_for_each_entry(info, &root->supers, node) {
+ list_for_each_entry(info, &kernfs_root(kn)->supers, node) {
struct inode *inode;
struct dentry *dentry;
@@ -833,6 +847,33 @@ void kernfs_notify(struct kernfs_node *kn)
}
mutex_unlock(&kernfs_mutex);
+ kernfs_put(kn);
+ goto repeat;
+}
+
+/**
+ * kernfs_notify - notify a kernfs file
+ * @kn: file to notify
+ *
+ * Notify @kn such that poll(2) on @kn wakes up. Maybe be called from any
+ * context.
+ */
+void kernfs_notify(struct kernfs_node *kn)
+{
+ static DECLARE_WORK(kernfs_notify_work, kernfs_notify_workfn);
+ unsigned long flags;
+
+ if (WARN_ON(kernfs_type(kn) != KERNFS_FILE))
+ return;
+
+ spin_lock_irqsave(&kernfs_notify_lock, flags);
+ if (!kn->attr.notify_next) {
+ kernfs_get(kn);
+ kn->attr.notify_next = kernfs_notify_list;
+ kernfs_notify_list = kn;
+ schedule_work(&kernfs_notify_work);
+ }
+ spin_unlock_irqrestore(&kernfs_notify_lock, flags);
}
EXPORT_SYMBOL_GPL(kernfs_notify);
diff --git a/include/linux/kernfs.h b/include/linux/kernfs.h
index 17aa1cce6f8e..145375ea0bd9 100644
--- a/include/linux/kernfs.h
+++ b/include/linux/kernfs.h
@@ -91,6 +91,7 @@ struct kernfs_elem_attr {
const struct kernfs_ops *ops;
struct kernfs_open_node *open;
loff_t size;
+ struct kernfs_node *notify_next; /* for kernfs_notify() */
};
/*
diff --git a/lib/lz4/lz4_decompress.c b/lib/lz4/lz4_decompress.c
index b74da447e81e..7a85967060a5 100644
--- a/lib/lz4/lz4_decompress.c
+++ b/lib/lz4/lz4_decompress.c
@@ -192,6 +192,8 @@ static int lz4_uncompress_unknownoutputsize(const char *source, char *dest,
int s = 255;
while ((ip < iend) && (s == 255)) {
s = *ip++;
+ if (unlikely(length > (size_t)(length + s)))
+ goto _output_error;
length += s;
}
}
@@ -232,6 +234,8 @@ static int lz4_uncompress_unknownoutputsize(const char *source, char *dest,
if (length == ML_MASK) {
while (ip < iend) {
int s = *ip++;
+ if (unlikely(length > (size_t)(length + s)))
+ goto _output_error;
length += s;
if (s == 255)
continue;
@@ -284,7 +288,7 @@ static int lz4_uncompress_unknownoutputsize(const char *source, char *dest,
/* write overflow error detected */
_output_error:
- return (int) (-(((char *) ip) - source));
+ return -1;
}
int lz4_decompress(const unsigned char *src, size_t *src_len,