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, 398 insertions, 0 deletions

diff --git a/fs/orangefs/dir.c b/fs/orangefs/dir.c
new file mode 100644
index 000000000..115b2c2f5
--- /dev/null
+++ b/fs/orangefs/dir.c
@@ -0,0 +1,398 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2017 Omnibond Systems, L.L.C.
+ */
+
+#include <linux/filelock.h>
+#include "protocol.h"
+#include "orangefs-kernel.h"
+#include "orangefs-bufmap.h"
+
+struct orangefs_dir_part {
+	struct orangefs_dir_part *next;
+	size_t len;
+};
+
+struct orangefs_dir {
+	__u64 token;
+	struct orangefs_dir_part *part;
+	loff_t end;
+	int error;
+};
+
+#define PART_SHIFT (24)
+#define PART_SIZE (1<<24)
+#define PART_MASK (~(PART_SIZE - 1))
+
+/*
+ * There can be up to 512 directory entries.  Each entry is encoded as
+ * follows:
+ * 4 bytes: string size (n)
+ * n bytes: string
+ * 1 byte: trailing zero
+ * padding to 8 bytes
+ * 16 bytes: khandle
+ * padding to 8 bytes
+ *
+ * The trailer_buf starts with a struct orangefs_readdir_response_s
+ * which must be skipped to get to the directory data.
+ *
+ * The data which is received from the userspace daemon is termed a
+ * part and is stored in a linked list in case more than one part is
+ * needed for a large directory.
+ *
+ * The position pointer (ctx->pos) encodes the part and offset on which
+ * to begin reading at.  Bits above PART_SHIFT encode the part and bits
+ * below PART_SHIFT encode the offset.  Parts are stored in a linked
+ * list which grows as data is received from the server.  The overhead
+ * associated with managing the list is presumed to be small compared to
+ * the overhead of communicating with the server.
+ *
+ * As data is received from the server, it is placed at the end of the
+ * part list.  Data is parsed from the current position as it is needed.
+ * When data is determined to be corrupt, it is either because the
+ * userspace component has sent back corrupt data or because the file
+ * pointer has been moved to an invalid location.  Since the two cannot
+ * be differentiated, return EIO.
+ *
+ * Part zero is synthesized to contains `.' and `..'.  Part one is the
+ * first part of the part list.
+ */
+
+static int do_readdir(struct orangefs_dir *od, struct inode *inode,
+    struct orangefs_kernel_op_s *op)
+{
+	struct orangefs_inode_s *oi = ORANGEFS_I(inode);
+	struct orangefs_readdir_response_s *resp;
+	int bufi, r;
+
+	/*
+	 * Despite the badly named field, readdir does not use shared
+	 * memory.  However, there are a limited number of readdir
+	 * slots, which must be allocated here.  This flag simply tells
+	 * the op scheduler to return the op here for retry.
+	 */
+	op->uses_shared_memory = 1;
+	op->upcall.req.readdir.refn = oi->refn;
+	op->upcall.req.readdir.token = od->token;
+	op->upcall.req.readdir.max_dirent_count =
+	    ORANGEFS_MAX_DIRENT_COUNT_READDIR;
+
+again:
+	bufi = orangefs_readdir_index_get();
+	if (bufi < 0) {
+		od->error = bufi;
+		return bufi;
+	}
+
+	op->upcall.req.readdir.buf_index = bufi;
+
+	r = service_operation(op, "orangefs_readdir",
+	    get_interruptible_flag(inode));
+
+	orangefs_readdir_index_put(bufi);
+
+	if (op_state_purged(op)) {
+		if (r == -EAGAIN) {
+			vfree(op->downcall.trailer_buf);
+			goto again;
+		} else if (r == -EIO) {
+			vfree(op->downcall.trailer_buf);
+			od->error = r;
+			return r;
+		}
+	}
+
+	if (r < 0) {
+		vfree(op->downcall.trailer_buf);
+		od->error = r;
+		return r;
+	} else if (op->downcall.status) {
+		vfree(op->downcall.trailer_buf);
+		od->error = op->downcall.status;
+		return op->downcall.status;
+	}
+
+	/*
+	 * The maximum size is size per entry times the 512 entries plus
+	 * the header.  This is well under the limit.
+	 */
+	if (op->downcall.trailer_size > PART_SIZE) {
+		vfree(op->downcall.trailer_buf);
+		od->error = -EIO;
+		return -EIO;
+	}
+
+	resp = (struct orangefs_readdir_response_s *)
+	    op->downcall.trailer_buf;
+	od->token = resp->token;
+	return 0;
+}
+
+static int parse_readdir(struct orangefs_dir *od,
+    struct orangefs_kernel_op_s *op)
+{
+	struct orangefs_dir_part *part, *new;
+	size_t count;
+
+	count = 1;
+	part = od->part;
+	while (part) {
+		count++;
+		if (part->next)
+			part = part->next;
+		else
+			break;
+	}
+
+	new = (void *)op->downcall.trailer_buf;
+	new->next = NULL;
+	new->len = op->downcall.trailer_size -
+	    sizeof(struct orangefs_readdir_response_s);
+	if (!od->part)
+		od->part = new;
+	else
+		part->next = new;
+	count++;
+	od->end = count << PART_SHIFT;
+
+	return 0;
+}
+
+static int orangefs_dir_more(struct orangefs_dir *od, struct inode *inode)
+{
+	struct orangefs_kernel_op_s *op;
+	int r;
+
+	op = op_alloc(ORANGEFS_VFS_OP_READDIR);
+	if (!op) {
+		od->error = -ENOMEM;
+		return -ENOMEM;
+	}
+	r = do_readdir(od, inode, op);
+	if (r) {
+		od->error = r;
+		goto out;
+	}
+	r = parse_readdir(od, op);
+	if (r) {
+		od->error = r;
+		goto out;
+	}
+
+	od->error = 0;
+out:
+	op_release(op);
+	return od->error;
+}
+
+static int fill_from_part(struct orangefs_dir_part *part,
+    struct dir_context *ctx)
+{
+	const int offset = sizeof(struct orangefs_readdir_response_s);
+	struct orangefs_khandle *khandle;
+	__u32 *len;
+	u64 padlen;
+	loff_t i;
+	char *s;
+	i = ctx->pos & ~PART_MASK;
+
+	/* The file offset from userspace is too large. */
+	if (i > part->len)
+		return 1;
+
+	/*
+	 * If the seek pointer is positioned just before an entry it
+	 * should find the next entry.
+	 */
+	if (i % 8)
+		i = i + (8 - i%8)%8;
+
+	while (i < part->len) {
+		if (part->len < i + sizeof *len)
+			break;
+		len = (void *)part + offset + i;
+		/*
+		 * len is the size of the string itself.  padlen is the
+		 * total size of the encoded string.
+		 */
+		padlen = (u64)sizeof *len + *len + 1;
+		padlen += (8 - padlen % 8) % 8;
+		if (part->len < i + padlen + sizeof *khandle)
+			goto next;
+		s = (void *)part + offset + i + sizeof *len;
+		if (s[*len] != 0)
+			goto next;
+		khandle = (void *)part + offset + i + padlen;
+		if (!dir_emit(ctx, s, *len,
+		    orangefs_khandle_to_ino(khandle),
+		    DT_UNKNOWN))
+			return 0;
+		i += padlen + sizeof *khandle;
+		i = i + (8 - i%8)%8;
+		BUG_ON(i > part->len);
+		ctx->pos = (ctx->pos & PART_MASK) | i;
+		continue;
+next:
+		i += 8;
+	}
+	return 1;
+}
+
+static int orangefs_dir_fill(struct orangefs_dir *od, struct dir_context *ctx)
+{
+	struct orangefs_dir_part *part;
+	size_t count;
+
+	count = ((ctx->pos & PART_MASK) >> PART_SHIFT) - 1;
+
+	part = od->part;
+	while (part->next && count) {
+		count--;
+		part = part->next;
+	}
+	/* This means the userspace file offset is invalid. */
+	if (count) {
+		od->error = -EIO;
+		return -EIO;
+	}
+
+	while (part && part->len) {
+		int r;
+		r = fill_from_part(part, ctx);
+		if (r < 0) {
+			od->error = r;
+			return r;
+		} else if (r == 0) {
+			/* Userspace buffer is full. */
+			break;
+		} else {
+			/*
+			 * The part ran out of data.  Move to the next
+			 * part. */
+			ctx->pos = (ctx->pos & PART_MASK) +
+			    (1 << PART_SHIFT);
+			part = part->next;
+		}
+	}
+	return 0;
+}
+
+static loff_t orangefs_dir_llseek(struct file *file, loff_t offset,
+    int whence)
+{
+	struct orangefs_dir *od = file->private_data;
+	/*
+	 * Delete the stored data so userspace sees new directory
+	 * entries.
+	 */
+	if (!whence && offset < od->end) {
+		struct orangefs_dir_part *part = od->part;
+		while (part) {
+			struct orangefs_dir_part *next = part->next;
+			vfree(part);
+			part = next;
+		}
+		od->token = ORANGEFS_ITERATE_START;
+		od->part = NULL;
+		od->end = 1 << PART_SHIFT;
+	}
+	return default_llseek(file, offset, whence);
+}
+
+static int orangefs_dir_iterate(struct file *file,
+    struct dir_context *ctx)
+{
+	struct orangefs_dir *od = file->private_data;
+	struct inode *inode = file_inode(file);
+	int r;
+
+	if (od->error)
+		return od->error;
+
+	if (ctx->pos == 0) {
+		if (!dir_emit_dot(file, ctx))
+			return 0;
+		ctx->pos++;
+	}
+	if (ctx->pos == 1) {
+		if (!dir_emit_dotdot(file, ctx))
+			return 0;
+		ctx->pos = 1 << PART_SHIFT;
+	}
+
+	/*
+	 * The seek position is in the first synthesized part but is not
+	 * valid.
+	 */
+	if ((ctx->pos & PART_MASK) == 0)
+		return -EIO;
+
+	r = 0;
+
+	/*
+	 * Must read more if the user has sought past what has been read
+	 * so far.  Stop a user who has sought past the end.
+	 */
+	while (od->token != ORANGEFS_ITERATE_END &&
+	    ctx->pos > od->end) {
+		r = orangefs_dir_more(od, inode);
+		if (r)
+			return r;
+	}
+	if (od->token == ORANGEFS_ITERATE_END && ctx->pos > od->end)
+		return -EIO;
+
+	/* Then try to fill if there's any left in the buffer. */
+	if (ctx->pos < od->end) {
+		r = orangefs_dir_fill(od, ctx);
+		if (r)
+			return r;
+	}
+
+	/* Finally get some more and try to fill. */
+	if (od->token != ORANGEFS_ITERATE_END) {
+		r = orangefs_dir_more(od, inode);
+		if (r)
+			return r;
+		r = orangefs_dir_fill(od, ctx);
+	}
+
+	return r;
+}
+
+static int orangefs_dir_open(struct inode *inode, struct file *file)
+{
+	struct orangefs_dir *od;
+	file->private_data = kmalloc_obj(struct orangefs_dir);
+	if (!file->private_data)
+		return -ENOMEM;
+	od = file->private_data;
+	od->token = ORANGEFS_ITERATE_START;
+	od->part = NULL;
+	od->end = 1 << PART_SHIFT;
+	od->error = 0;
+	return 0;
+}
+
+static int orangefs_dir_release(struct inode *inode, struct file *file)
+{
+	struct orangefs_dir *od = file->private_data;
+	struct orangefs_dir_part *part = od->part;
+	while (part) {
+		struct orangefs_dir_part *next = part->next;
+		vfree(part);
+		part = next;
+	}
+	kfree(od);
+	return 0;
+}
+
+const struct file_operations orangefs_dir_operations = {
+	.llseek = orangefs_dir_llseek,
+	.read = generic_read_dir,
+	.iterate_shared = orangefs_dir_iterate,
+	.open = orangefs_dir_open,
+	.release = orangefs_dir_release,
+	.setlease = generic_setlease,
+};