Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 116 insertions, 0 deletions

diff --git a/fs/ext2/xattr.h b/fs/ext2/xattr.h
new file mode 100644
index 000000000..6a4966949
--- /dev/null
+++ b/fs/ext2/xattr.h
@@ -0,0 +1,116 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+  File: linux/ext2_xattr.h
+
+  On-disk format of extended attributes for the ext2 filesystem.
+
+  (C) 2001 Andreas Gruenbacher, <a.gruenbacher@computer.org>
+*/
+
+#include <linux/init.h>
+#include <linux/xattr.h>
+
+/* Magic value in attribute blocks */
+#define EXT2_XATTR_MAGIC		0xEA020000
+
+/* Maximum number of references to one attribute block */
+#define EXT2_XATTR_REFCOUNT_MAX		1024
+
+/* Name indexes */
+#define EXT2_XATTR_INDEX_USER			1
+#define EXT2_XATTR_INDEX_POSIX_ACL_ACCESS	2
+#define EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT	3
+#define EXT2_XATTR_INDEX_TRUSTED		4
+#define	EXT2_XATTR_INDEX_LUSTRE			5
+#define EXT2_XATTR_INDEX_SECURITY	        6
+
+struct ext2_xattr_header {
+	__le32	h_magic;	/* magic number for identification */
+	__le32	h_refcount;	/* reference count */
+	__le32	h_blocks;	/* number of disk blocks used */
+	__le32	h_hash;		/* hash value of all attributes */
+	__u32	h_reserved[4];	/* zero right now */
+};
+
+struct ext2_xattr_entry {
+	__u8	e_name_len;	/* length of name */
+	__u8	e_name_index;	/* attribute name index */
+	__le16	e_value_offs;	/* offset in disk block of value */
+	__le32	e_value_block;	/* disk block attribute is stored on (n/i) */
+	__le32	e_value_size;	/* size of attribute value */
+	__le32	e_hash;		/* hash value of name and value */
+	char	e_name[];	/* attribute name */
+};
+
+#define EXT2_XATTR_PAD_BITS		2
+#define EXT2_XATTR_PAD		(1<<EXT2_XATTR_PAD_BITS)
+#define EXT2_XATTR_ROUND		(EXT2_XATTR_PAD-1)
+#define EXT2_XATTR_LEN(name_len) \
+	(((name_len) + EXT2_XATTR_ROUND + \
+	sizeof(struct ext2_xattr_entry)) & ~EXT2_XATTR_ROUND)
+#define EXT2_XATTR_NEXT(entry) \
+	( (struct ext2_xattr_entry *)( \
+	  (char *)(entry) + EXT2_XATTR_LEN((entry)->e_name_len)) )
+#define EXT2_XATTR_SIZE(size) \
+	(((size) + EXT2_XATTR_ROUND) & ~EXT2_XATTR_ROUND)
+
+struct mb_cache;
+
+# ifdef CONFIG_EXT2_FS_XATTR
+
+extern const struct xattr_handler ext2_xattr_user_handler;
+extern const struct xattr_handler ext2_xattr_trusted_handler;
+extern const struct xattr_handler ext2_xattr_security_handler;
+
+extern ssize_t ext2_listxattr(struct dentry *, char *, size_t);
+
+extern int ext2_xattr_get(struct inode *, int, const char *, void *, size_t);
+extern int ext2_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
+
+extern void ext2_xattr_delete_inode(struct inode *);
+
+extern struct mb_cache *ext2_xattr_create_cache(void);
+extern void ext2_xattr_destroy_cache(struct mb_cache *cache);
+
+extern const struct xattr_handler * const ext2_xattr_handlers[];
+
+# else  /* CONFIG_EXT2_FS_XATTR */
+
+static inline int
+ext2_xattr_get(struct inode *inode, int name_index,
+	       const char *name, void *buffer, size_t size)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline int
+ext2_xattr_set(struct inode *inode, int name_index, const char *name,
+	       const void *value, size_t size, int flags)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline void
+ext2_xattr_delete_inode(struct inode *inode)
+{
+}
+
+static inline void ext2_xattr_destroy_cache(struct mb_cache *cache)
+{
+}
+
+#define ext2_xattr_handlers NULL
+#define ext2_listxattr NULL
+
+# endif  /* CONFIG_EXT2_FS_XATTR */
+
+#ifdef CONFIG_EXT2_FS_SECURITY
+extern int ext2_init_security(struct inode *inode, struct inode *dir,
+			      const struct qstr *qstr);
+#else
+static inline int ext2_init_security(struct inode *inode, struct inode *dir,
+				     const struct qstr *qstr)
+{
+	return 0;
+}
+#endif