Merge tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Don't destroy user event fields when removal fails

   User event fields are destroyed before the event is removed from
   visibility. But that can fail leaving the still visible event with no
   fields. Move the destroying of the fields to after the event is
   successfully removed from visibility.

 - Initialize function graph state is fork before calling
   copy_exec_state()

   For non-CLONE_VM forks, copy_exec_state() allocates a new
   task_exec_state. If that allocation fails, ftrace_graph_exit_task()
   will free the tasks ret_stack pointer. Since that pointer is still
   using the parent's ret_stack, it mistakenly frees the parent's
   pointer too.

   Call ftrace_graph_init() on the task first which will NULL out the
   new tasks's ret_stack and if the copy fails, it will not free
   anything.

 - Remove FGRAPH_MAX_INDEX

   The macro FGRAPH_MAX_INDEX was added but never used. Remove it.

 - Save ent_size in function graph printing of nested functions

   The function graph tracer needs to look at the next event to see if
   the next event is the return of the current function entry. If it is,
   it prints a single line:

	ktime_get();

   Otherwise it prints it like a nested function:

	tick_nohz_irq_exit() {
	    ktime_get();
	    kcpustat_irq_exit();
	}

   In order to look at the next event, it must save the current event so
   that it has the information to print from it. It saves the event in
   the iterator descriptor called "ent". What it doesn't save is the
   ent_size of the event which is now used to know if the function graph
   arguments are to be printed. The peek doesn't save the size so the
   size used happens to be that of the size of the last event that was
   seen.

   Save the entry event size in the iterator descriptor so that the
   correct size is used.

 - Fix several errors with freeing data in the histogram code

   The histogram code had a lot of leaked or or incorrect accounting
   when failures happen. Correct them.

 - Fix histogram regression of .percent and .graph modifiers

   Up until 6.3 histogram values could have "percent" or "graph"
   modifiers that changed how they were printed. But a change that added
   restricting histograms values from being strings, stack traces and
   other modifiers inadvertently prevented them from using the percent
   and graph modifiers, which were legal use cases for values.

   Put back the percent and graph modifiers.

 - Fix various typos in the comments

 - Set the trace_clock before initializing a histogram with clock
   argument

   The histogram API allows the user to specific which trace clock to
   use via a "clock=" string. The histogram is set up first before the
   clock is checked. If the passed in clock is not valid, it exits
   without fully fixing up the histogram leaving it on the list and a
   use-after-free can trigger.

   Update the clock argument first and if it fails then exit gracefully
   before the histogram trigger is placed on any lists.

 - Restore :mod: trailer after parsing in ftrace_set_clr_event

   The function ftrace_set_clr_event() modifies the parse string and
   needs to put it back to what was passed in. It searches for ":mod:"
   via a strsep() but fails to put back the first ':' in the string.

   Add back the ':' in the passed in string.

 - Take trace_array reference when opening a tracer options file

   The options files are dynamically created and some tracers add their
   own options. When a tracer adds their own list of options, the
   trace_array holding them has an array to hold the list of options for
   each tracer. This array increases in size via a krealloc(), and the
   new entry gets a newly allocated array to hold the options of the new
   tracer being added.

   The element in each entry of the tracer's option array holds a
   pointer back to the trace_array, a pointer to the tracer it is
   associated to, a pointer to the flags of the option.

   The issue is that these arrays are freed when the trace_array is
   freed when its instance it represents is removed from the instances
   directory. There's a race that an open of one of these options files
   can happen when the instance is being removed.

   Add a new helper function to be called by the open function of the
   options file to iterate all existing trace_arrays under a lock and
   find the one that has the given option element in one of it's tracer
   arrays. If found, then update the associated trace_array's reference
   counter to keep it from being freed. If not found, have the open call
   return -ENODEV.

 - Disable interrupts when acquiring the lock in rb_wake_up_waiters()

   The function rb_wake_up_waiters() assumes it will be called in
   interrupt context and does not disable irqs when taking
   cpu_buffer->reader_lock, which can be called in hard interrupt
   context. The issue is in PREEMPT_RT, this function is called in
   thread context leaving this lock open to a deadlock.

   Take the lock with interrupts disabled.

 - Use rcu_assign_pointer() for tmp_ops filter hash

   The tmp_ops used in update_ftrace_direct_mod() assigns its
   filter_hash field directly, but that field is annotated as __rcu and
   sparse complains. Assign it with rcu_assign_pointer()

 - Fix use-after-free in enable_trigger_private_data_free()

   The trace_event_call is accessed through the event_trigger_data's
   trace_event_file pointer to put the trace_event_call on freeing. The
   issue is that the trace_event_file data may have been freed already
   causing a use-after-free. Add a field to the event_trigger_data that
   points directly to the trace_event_call so that it can decrement its
   reference directly without needing to go through the
   trace_event_file.

 - Fix accounting of buffer data remote headers

   trace_buffer_desc_size() and trace_remote_alloc_buffer() undercount
   the number of pages is needed for the asked for size as it doesn't
   take into account the meta data on each page. Add a helper function
   to do the calculation properly and use that in these functions.

 - Catch nr_page_va overflow in ring_buffer_desc sizing

   The number of pages per remote ring buffer is capped by
   ring_buffer_desc::nr_page_va (32 bits). A buffer_size large enough to
   overflow that field would silently allocate a descriptor smaller than
   what was asked for.

 - Do not resize the subbuf order if any per_cpu buffer is disabled

   The mmapping of ring buffers disables resizing the subbuffers, but it
   is done per-cpu whereas the subbuf size change is done for all the
   per_cpu buffers under the buffer->mutex. It could change the size of
   some while the mapping is happening on others. Have the resize of the
   subbuf order check all the per_cpu buffers under the lock to see if
   any of them is disabled before starting and causing an inconsistency
   between buffers that are being mapped.

* tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (25 commits)
  ring-buffer: Check resize_disabled before publishing the new subbuf order
  tracing/remotes: Catch nr_page_va overflow in ring_buffer_desc sizing
  tracing/remotes: Account for ring buffer page header in size calculation
  tracing: Don't dereference trace_event_file in deferred trigger free
  ftrace: Use rcu_assign_pointer() for tmp_ops filter hash
  ring-buffer: Acquire the lock with irqsave in rb_wake_up_waiters()
  tracing: Take trace_array reference when opening a tracer options file
  tracing: Fix ring_buffer_read_page_size() kernel-doc
  tracing: Restore :mod: trailer after parsing in ftrace_set_clr_event()
  tracing: Fix memory corruption from a "STACKTRACE" histogram key
  tracing: Fix memory corruption from the histogram stacktrace modifier
  tracing: Undo the registration when enabling the histogram trigger fails
  tracing: Take the reference before publishing the named histogram trigger
  tracing: Set the trace clock before registering the histogram trigger
  tracing: Fix typo "preceeded" in comment
  tracing: Fix typo "availabe" in comment
  tracing: Let histogram values keep the percent and graph modifiers
  tracing: Keep the entry count when the histogram stats allocation fails
  tracing: Free histogram the field rejected for a bad modifier
  tracing: Free histogram the var ref when its initialization fails
  ...

1 files changed, 380 insertions, 0 deletions

diff --git a/fs/sync.c b/fs/sync.c
new file mode 100644
index 000000000..4a84dd837
--- /dev/null
+++ b/fs/sync.c
@@ -0,0 +1,380 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * High-level sync()-related operations
+ */
+
+#include <linux/blkdev.h>
+#include <linux/kernel.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include <linux/export.h>
+#include <linux/namei.h>
+#include <linux/sched.h>
+#include <linux/writeback.h>
+#include <linux/syscalls.h>
+#include <linux/linkage.h>
+#include <linux/pagemap.h>
+#include <linux/quotaops.h>
+#include <linux/backing-dev.h>
+#include "internal.h"
+
+#define VALID_FLAGS (SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE| \
+			SYNC_FILE_RANGE_WAIT_AFTER)
+
+/*
+ * Write out and wait upon all dirty data associated with this
+ * superblock.  Filesystem data as well as the underlying block
+ * device.  Takes the superblock lock.
+ */
+int sync_filesystem(struct super_block *sb)
+{
+	int ret = 0;
+
+	/*
+	 * We need to be protected against the filesystem going from
+	 * r/o to r/w or vice versa.
+	 */
+	WARN_ON(!rwsem_is_locked(&sb->s_umount));
+
+	/*
+	 * No point in syncing out anything if the filesystem is read-only.
+	 */
+	if (sb_rdonly(sb))
+		return 0;
+
+	/*
+	 * Do the filesystem syncing work.  For simple filesystems
+	 * writeback_inodes_sb(sb) just dirties buffers with inodes so we have
+	 * to submit I/O for these buffers via sync_blockdev().  This also
+	 * speeds up the wait == 1 case since in that case write_inode()
+	 * methods call sync_dirty_buffer() and thus effectively write one block
+	 * at a time.
+	 */
+	writeback_inodes_sb(sb, WB_REASON_SYNC);
+	if (sb->s_op->sync_fs) {
+		ret = sb->s_op->sync_fs(sb, 0);
+		if (ret)
+			return ret;
+	}
+	ret = sync_blockdev_nowait(sb->s_bdev);
+	if (ret)
+		return ret;
+
+	sync_inodes_sb(sb);
+	if (sb->s_op->sync_fs) {
+		ret = sb->s_op->sync_fs(sb, 1);
+		if (ret)
+			return ret;
+	}
+	return sync_blockdev(sb->s_bdev);
+}
+EXPORT_SYMBOL(sync_filesystem);
+
+static void sync_inodes_one_sb(struct super_block *sb, void *arg)
+{
+	if (!sb_rdonly(sb))
+		sync_inodes_sb(sb);
+}
+
+static void sync_fs_one_sb(struct super_block *sb, void *arg)
+{
+	if (!sb_rdonly(sb) && !(sb->s_iflags & SB_I_SKIP_SYNC) &&
+	    sb->s_op->sync_fs)
+		sb->s_op->sync_fs(sb, *(int *)arg);
+}
+
+/*
+ * Sync everything. We start by waking flusher threads so that most of
+ * writeback runs on all devices in parallel. Then we sync all inodes reliably
+ * which effectively also waits for all flusher threads to finish doing
+ * writeback. At this point all data is on disk so metadata should be stable
+ * and we tell filesystems to sync their metadata via ->sync_fs() calls.
+ * Finally, we writeout all block devices because some filesystems (e.g. ext2)
+ * just write metadata (such as inodes or bitmaps) to block device page cache
+ * and do not sync it on their own in ->sync_fs().
+ */
+void ksys_sync(void)
+{
+	int nowait = 0, wait = 1;
+
+	wakeup_flusher_threads(WB_REASON_SYNC);
+	iterate_supers(sync_inodes_one_sb, NULL);
+	iterate_supers(sync_fs_one_sb, &nowait);
+	iterate_supers(sync_fs_one_sb, &wait);
+	sync_bdevs(false);
+	sync_bdevs(true);
+}
+
+SYSCALL_DEFINE0(sync)
+{
+	ksys_sync();
+	return 0;
+}
+
+static void do_sync_work(struct work_struct *work)
+{
+	int nowait = 0;
+	int wait = 1;
+
+	/*
+	 * Sync twice to reduce the possibility we skipped some inodes / pages
+	 * because they were temporarily locked
+	 */
+	iterate_supers(sync_inodes_one_sb, NULL);
+	iterate_supers(sync_fs_one_sb, &nowait);
+	sync_bdevs(false);
+	iterate_supers(sync_inodes_one_sb, NULL);
+	iterate_supers(sync_fs_one_sb, &wait);
+	sync_bdevs(false);
+	printk("Emergency Sync complete\n");
+	kfree(work);
+}
+
+void emergency_sync(void)
+{
+	struct work_struct *work;
+
+	work = kmalloc_obj(*work, GFP_ATOMIC);
+	if (work) {
+		INIT_WORK(work, do_sync_work);
+		schedule_work(work);
+	}
+}
+
+/*
+ * sync a single super
+ */
+SYSCALL_DEFINE1(syncfs, int, fd)
+{
+	CLASS(fd, f)(fd);
+	struct super_block *sb;
+	int ret, ret2;
+
+	if (fd_empty(f))
+		return -EBADF;
+	sb = fd_file(f)->f_path.dentry->d_sb;
+
+	down_read(&sb->s_umount);
+	ret = sync_filesystem(sb);
+	up_read(&sb->s_umount);
+
+	ret2 = errseq_check_and_advance(&sb->s_wb_err, &fd_file(f)->f_sb_err);
+
+	return ret ? ret : ret2;
+}
+
+/**
+ * vfs_fsync_range - helper to sync a range of data & metadata to disk
+ * @file:		file to sync
+ * @start:		offset in bytes of the beginning of data range to sync
+ * @end:		offset in bytes of the end of data range (inclusive)
+ * @datasync:		perform only datasync
+ *
+ * Write back data in range @start..@end and metadata for @file to disk.  If
+ * @datasync is set only metadata needed to access modified file data is
+ * written.
+ */
+int vfs_fsync_range(struct file *file, loff_t start, loff_t end, int datasync)
+{
+	struct inode *inode = file->f_mapping->host;
+
+	if (!file->f_op->fsync)
+		return -EINVAL;
+	if (!datasync)
+		sync_lazytime(inode);
+	return file->f_op->fsync(file, start, end, datasync);
+}
+EXPORT_SYMBOL(vfs_fsync_range);
+
+/**
+ * vfs_fsync - perform a fsync or fdatasync on a file
+ * @file:		file to sync
+ * @datasync:		only perform a fdatasync operation
+ *
+ * Write back data and metadata for @file to disk.  If @datasync is
+ * set only metadata needed to access modified file data is written.
+ */
+int vfs_fsync(struct file *file, int datasync)
+{
+	return vfs_fsync_range(file, 0, LLONG_MAX, datasync);
+}
+EXPORT_SYMBOL(vfs_fsync);
+
+static int do_fsync(unsigned int fd, int datasync)
+{
+	CLASS(fd, f)(fd);
+
+	if (fd_empty(f))
+		return -EBADF;
+
+	return vfs_fsync(fd_file(f), datasync);
+}
+
+SYSCALL_DEFINE1(fsync, unsigned int, fd)
+{
+	return do_fsync(fd, 0);
+}
+
+SYSCALL_DEFINE1(fdatasync, unsigned int, fd)
+{
+	return do_fsync(fd, 1);
+}
+
+int sync_file_range(struct file *file, loff_t offset, loff_t nbytes,
+		    unsigned int flags)
+{
+	int ret;
+	struct address_space *mapping;
+	loff_t endbyte;			/* inclusive */
+	umode_t i_mode;
+
+	ret = -EINVAL;
+	if (flags & ~VALID_FLAGS)
+		goto out;
+
+	endbyte = offset + nbytes;
+
+	if ((s64)offset < 0)
+		goto out;
+	if ((s64)endbyte < 0)
+		goto out;
+	if (endbyte < offset)
+		goto out;
+
+	if (sizeof(pgoff_t) == 4) {
+		if (offset >= (0x100000000ULL << PAGE_SHIFT)) {
+			/*
+			 * The range starts outside a 32 bit machine's
+			 * pagecache addressing capabilities.  Let it "succeed"
+			 */
+			ret = 0;
+			goto out;
+		}
+		if (endbyte >= (0x100000000ULL << PAGE_SHIFT)) {
+			/*
+			 * Out to EOF
+			 */
+			nbytes = 0;
+		}
+	}
+
+	if (nbytes == 0)
+		endbyte = LLONG_MAX;
+	else
+		endbyte--;		/* inclusive */
+
+	i_mode = file_inode(file)->i_mode;
+	ret = -ESPIPE;
+	if (!S_ISREG(i_mode) && !S_ISBLK(i_mode) && !S_ISDIR(i_mode))
+		goto out;
+
+	mapping = file->f_mapping;
+	ret = 0;
+	if (flags & SYNC_FILE_RANGE_WAIT_BEFORE) {
+		ret = file_fdatawait_range(file, offset, endbyte);
+		if (ret < 0)
+			goto out;
+	}
+
+	if (flags & SYNC_FILE_RANGE_WRITE) {
+		if ((flags & SYNC_FILE_RANGE_WRITE_AND_WAIT) ==
+			     SYNC_FILE_RANGE_WRITE_AND_WAIT)
+			ret = filemap_fdatawrite_range(mapping, offset,
+					endbyte);
+		else
+			ret = filemap_flush_range(mapping, offset, endbyte);
+		if (ret < 0)
+			goto out;
+	}
+
+	if (flags & SYNC_FILE_RANGE_WAIT_AFTER)
+		ret = file_fdatawait_range(file, offset, endbyte);
+
+out:
+	return ret;
+}
+
+/*
+ * ksys_sync_file_range() permits finely controlled syncing over a segment of
+ * a file in the range offset .. (offset+nbytes-1) inclusive.  If nbytes is
+ * zero then ksys_sync_file_range() will operate from offset out to EOF.
+ *
+ * The flag bits are:
+ *
+ * SYNC_FILE_RANGE_WAIT_BEFORE: wait upon writeout of all pages in the range
+ * before performing the write.
+ *
+ * SYNC_FILE_RANGE_WRITE: initiate writeout of all those dirty pages in the
+ * range which are not presently under writeback. Note that this may block for
+ * significant periods due to exhaustion of disk request structures.
+ *
+ * SYNC_FILE_RANGE_WAIT_AFTER: wait upon writeout of all pages in the range
+ * after performing the write.
+ *
+ * Useful combinations of the flag bits are:
+ *
+ * SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE: ensures that all pages
+ * in the range which were dirty on entry to ksys_sync_file_range() are placed
+ * under writeout.  This is a start-write-for-data-integrity operation.
+ *
+ * SYNC_FILE_RANGE_WRITE: start writeout of all dirty pages in the range which
+ * are not presently under writeout.  This is an asynchronous flush-to-disk
+ * operation.  Not suitable for data integrity operations.
+ *
+ * SYNC_FILE_RANGE_WAIT_BEFORE (or SYNC_FILE_RANGE_WAIT_AFTER): wait for
+ * completion of writeout of all pages in the range.  This will be used after an
+ * earlier SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE operation to wait
+ * for that operation to complete and to return the result.
+ *
+ * SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE|SYNC_FILE_RANGE_WAIT_AFTER
+ * (a.k.a. SYNC_FILE_RANGE_WRITE_AND_WAIT):
+ * a traditional sync() operation.  This is a write-for-data-integrity operation
+ * which will ensure that all pages in the range which were dirty on entry to
+ * ksys_sync_file_range() are written to disk.  It should be noted that disk
+ * caches are not flushed by this call, so there are no guarantees here that the
+ * data will be available on disk after a crash.
+ *
+ *
+ * SYNC_FILE_RANGE_WAIT_BEFORE and SYNC_FILE_RANGE_WAIT_AFTER will detect any
+ * I/O errors or ENOSPC conditions and will return those to the caller, after
+ * clearing the EIO and ENOSPC flags in the address_space.
+ *
+ * It should be noted that none of these operations write out the file's
+ * metadata.  So unless the application is strictly performing overwrites of
+ * already-instantiated disk blocks, there are no guarantees here that the data
+ * will be available after a crash.
+ */
+int ksys_sync_file_range(int fd, loff_t offset, loff_t nbytes,
+			 unsigned int flags)
+{
+	CLASS(fd, f)(fd);
+
+	if (fd_empty(f))
+		return -EBADF;
+
+	return sync_file_range(fd_file(f), offset, nbytes, flags);
+}
+
+SYSCALL_DEFINE4(sync_file_range, int, fd, loff_t, offset, loff_t, nbytes,
+				unsigned int, flags)
+{
+	return ksys_sync_file_range(fd, offset, nbytes, flags);
+}
+
+#if defined(CONFIG_COMPAT) && defined(__ARCH_WANT_COMPAT_SYNC_FILE_RANGE)
+COMPAT_SYSCALL_DEFINE6(sync_file_range, int, fd, compat_arg_u64_dual(offset),
+		       compat_arg_u64_dual(nbytes), unsigned int, flags)
+{
+	return ksys_sync_file_range(fd, compat_arg_u64_glue(offset),
+				    compat_arg_u64_glue(nbytes), flags);
+}
+#endif
+
+/* It would be nice if people remember that not all the world's an i386
+   when they introduce new system calls */
+SYSCALL_DEFINE4(sync_file_range2, int, fd, unsigned int, flags,
+				 loff_t, offset, loff_t, nbytes)
+{
+	return ksys_sync_file_range(fd, offset, nbytes, flags);
+}