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, 448 insertions, 0 deletions

diff --git a/io_uring/openclose.c b/io_uring/openclose.c
new file mode 100644
index 000000000..c71242915
--- /dev/null
+++ b/io_uring/openclose.c
@@ -0,0 +1,448 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/fdtable.h>
+#include <linux/fsnotify.h>
+#include <linux/namei.h>
+#include <linux/pipe_fs_i.h>
+#include <linux/watch_queue.h>
+#include <linux/io_uring.h>
+
+#include <uapi/linux/io_uring.h>
+
+#include "../fs/internal.h"
+
+#include "filetable.h"
+#include "io_uring.h"
+#include "rsrc.h"
+#include "openclose.h"
+
+struct io_open {
+	struct file			*file;
+	int				dfd;
+	u32				file_slot;
+	struct delayed_filename		filename;
+	struct open_how			how;
+	unsigned long			nofile;
+};
+
+struct io_close {
+	struct file			*file;
+	int				fd;
+	u32				file_slot;
+};
+
+struct io_fixed_install {
+	struct file			*file;
+	unsigned int			o_flags;
+};
+
+static bool io_openat_force_async(struct io_open *open)
+{
+	/*
+	 * Don't bother trying for O_TRUNC, O_CREAT, or O_TMPFILE open,
+	 * it'll always -EAGAIN. Note that we test for __O_TMPFILE because
+	 * O_TMPFILE includes O_DIRECTORY, which isn't a flag we need to force
+	 * async for.
+	 */
+	return open->how.flags & (O_TRUNC | O_CREAT | __O_TMPFILE);
+}
+
+static int __io_openat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+	struct io_open *open = io_kiocb_to_cmd(req, struct io_open);
+	const char __user *fname;
+	int ret;
+
+	if (unlikely(sqe->buf_index))
+		return -EINVAL;
+	if (unlikely(req->flags & REQ_F_FIXED_FILE))
+		return -EBADF;
+
+	/* open.how should be already initialised */
+	if (!(open->how.flags & O_PATH) && force_o_largefile())
+		open->how.flags |= O_LARGEFILE;
+
+	open->dfd = READ_ONCE(sqe->fd);
+	fname = u64_to_user_ptr(READ_ONCE(sqe->addr));
+	ret = delayed_getname(&open->filename, fname);
+	if (unlikely(ret))
+		return ret;
+	req->flags |= REQ_F_NEED_CLEANUP;
+
+	open->file_slot = READ_ONCE(sqe->file_index);
+	if (open->file_slot && (open->how.flags & O_CLOEXEC))
+		return -EINVAL;
+
+	open->nofile = rlimit(RLIMIT_NOFILE);
+	if (io_openat_force_async(open))
+		req->flags |= REQ_F_FORCE_ASYNC;
+	return 0;
+}
+
+void io_openat_bpf_populate(struct io_uring_bpf_ctx *bctx, struct io_kiocb *req)
+{
+	struct io_open *open = io_kiocb_to_cmd(req, struct io_open);
+
+	bctx->open.flags = open->how.flags;
+	bctx->open.mode = open->how.mode;
+	bctx->open.resolve = open->how.resolve;
+}
+
+int io_openat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+	struct io_open *open = io_kiocb_to_cmd(req, struct io_open);
+	u64 mode = READ_ONCE(sqe->len);
+	u64 flags = READ_ONCE(sqe->open_flags);
+
+	open->how = build_open_how(flags, mode);
+	return __io_openat_prep(req, sqe);
+}
+
+int io_openat2_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+	struct io_open *open = io_kiocb_to_cmd(req, struct io_open);
+	struct open_how __user *how;
+	size_t len;
+	int ret;
+
+	how = u64_to_user_ptr(READ_ONCE(sqe->addr2));
+	len = READ_ONCE(sqe->len);
+	if (len < OPEN_HOW_SIZE_VER0)
+		return -EINVAL;
+
+	ret = copy_struct_from_user(&open->how, sizeof(open->how), how, len);
+	if (ret)
+		return ret;
+
+	return __io_openat_prep(req, sqe);
+}
+
+int io_openat2(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_open *open = io_kiocb_to_cmd(req, struct io_open);
+	struct open_flags op;
+	struct file *file;
+	bool resolve_nonblock, nonblock_set;
+	bool fixed = !!open->file_slot;
+	CLASS(filename_complete_delayed, name)(&open->filename);
+	int ret;
+
+	ret = build_open_flags(&open->how, &op);
+	if (ret)
+		goto err;
+	nonblock_set = op.open_flag & O_NONBLOCK;
+	resolve_nonblock = open->how.resolve & RESOLVE_CACHED;
+	if (issue_flags & IO_URING_F_NONBLOCK) {
+		WARN_ON_ONCE(io_openat_force_async(open));
+		op.lookup_flags |= LOOKUP_CACHED;
+		op.open_flag |= O_NONBLOCK;
+	}
+
+	if (!fixed) {
+		ret = __get_unused_fd_flags(open->how.flags, open->nofile);
+		if (ret < 0)
+			goto err;
+	}
+
+	file = do_file_open(open->dfd, name, &op);
+	if (IS_ERR(file)) {
+		/*
+		 * We could hang on to this 'fd' on retrying, but seems like
+		 * marginal gain for something that is now known to be a slower
+		 * path. So just put it, and we'll get a new one when we retry.
+		 */
+		if (!fixed)
+			put_unused_fd(ret);
+
+		ret = PTR_ERR(file);
+		/* only retry if RESOLVE_CACHED wasn't already set by application */
+		if (ret == -EAGAIN && !resolve_nonblock &&
+		    (issue_flags & IO_URING_F_NONBLOCK)) {
+			ret = putname_to_delayed(&open->filename,
+						 no_free_ptr(name));
+			if (likely(!ret))
+				return -EAGAIN;
+		}
+		goto err;
+	}
+
+	if ((issue_flags & IO_URING_F_NONBLOCK) && !nonblock_set)
+		file->f_flags &= ~O_NONBLOCK;
+
+	if (!fixed)
+		fd_install(ret, file);
+	else
+		ret = io_fixed_fd_install(req, issue_flags, file,
+						open->file_slot);
+err:
+	req->flags &= ~REQ_F_NEED_CLEANUP;
+	if (ret < 0)
+		req_set_fail(req);
+	io_req_set_res(req, ret, 0);
+	return IOU_COMPLETE;
+}
+
+int io_openat(struct io_kiocb *req, unsigned int issue_flags)
+{
+	return io_openat2(req, issue_flags);
+}
+
+void io_open_cleanup(struct io_kiocb *req)
+{
+	struct io_open *open = io_kiocb_to_cmd(req, struct io_open);
+
+	dismiss_delayed_filename(&open->filename);
+}
+
+int __io_close_fixed(struct io_ring_ctx *ctx, unsigned int issue_flags,
+		     unsigned int offset)
+{
+	int ret;
+
+	io_ring_submit_lock(ctx, issue_flags);
+	ret = io_fixed_fd_remove(ctx, offset);
+	io_ring_submit_unlock(ctx, issue_flags);
+
+	return ret;
+}
+
+static inline int io_close_fixed(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_close *close = io_kiocb_to_cmd(req, struct io_close);
+
+	return __io_close_fixed(req->ctx, issue_flags, close->file_slot - 1);
+}
+
+int io_close_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+	struct io_close *close = io_kiocb_to_cmd(req, struct io_close);
+
+	if (sqe->off || sqe->addr || sqe->len || sqe->rw_flags || sqe->buf_index)
+		return -EINVAL;
+	if (req->flags & REQ_F_FIXED_FILE)
+		return -EBADF;
+
+	close->fd = READ_ONCE(sqe->fd);
+	close->file_slot = READ_ONCE(sqe->file_index);
+	if (close->file_slot && close->fd)
+		return -EINVAL;
+
+	return 0;
+}
+
+int io_close(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct files_struct *files = current->files;
+	struct io_close *close = io_kiocb_to_cmd(req, struct io_close);
+	struct file *file;
+	int ret = -EBADF;
+
+	if (close->file_slot) {
+		ret = io_close_fixed(req, issue_flags);
+		goto err;
+	}
+
+	spin_lock(&files->file_lock);
+	file = files_lookup_fd_locked(files, close->fd);
+	if (!file || io_is_uring_fops(file)) {
+		spin_unlock(&files->file_lock);
+		goto err;
+	}
+
+	/* if the file has a flush method, be safe and punt to async */
+	if (file->f_op->flush && (issue_flags & IO_URING_F_NONBLOCK)) {
+		spin_unlock(&files->file_lock);
+		return -EAGAIN;
+	}
+
+	file = file_close_fd_locked(files, close->fd);
+	spin_unlock(&files->file_lock);
+	if (!file)
+		goto err;
+
+	/* No ->flush() or already async, safely close from here */
+	ret = filp_close(file, current->files);
+err:
+	if (ret < 0)
+		req_set_fail(req);
+	io_req_set_res(req, ret, 0);
+	return IOU_COMPLETE;
+}
+
+int io_install_fixed_fd_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+	struct io_fixed_install *ifi;
+	unsigned int flags;
+
+	if (sqe->off || sqe->addr || sqe->len || sqe->buf_index ||
+	    sqe->splice_fd_in || sqe->addr3)
+		return -EINVAL;
+
+	/* must be a fixed file */
+	if (!(req->flags & REQ_F_FIXED_FILE))
+		return -EBADF;
+
+	flags = READ_ONCE(sqe->install_fd_flags);
+	if (flags & ~IORING_FIXED_FD_NO_CLOEXEC)
+		return -EINVAL;
+
+	/* ensure the task's creds are used when installing/receiving fds */
+	if (req->flags & REQ_F_CREDS)
+		return -EPERM;
+
+	/* default to O_CLOEXEC, disable if IORING_FIXED_FD_NO_CLOEXEC is set */
+	ifi = io_kiocb_to_cmd(req, struct io_fixed_install);
+	ifi->o_flags = O_CLOEXEC;
+	if (flags & IORING_FIXED_FD_NO_CLOEXEC)
+		ifi->o_flags = 0;
+
+	return 0;
+}
+
+int io_install_fixed_fd(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_fixed_install *ifi;
+	int ret;
+
+	ifi = io_kiocb_to_cmd(req, struct io_fixed_install);
+	ret = receive_fd(req->file, NULL, ifi->o_flags);
+	if (ret < 0)
+		req_set_fail(req);
+	io_req_set_res(req, ret, 0);
+	return IOU_COMPLETE;
+}
+
+struct io_pipe {
+	struct file *file;
+	int __user *fds;
+	int flags;
+	int file_slot;
+	unsigned long nofile;
+};
+
+int io_pipe_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+	struct io_pipe *p = io_kiocb_to_cmd(req, struct io_pipe);
+
+	if (sqe->fd || sqe->off || sqe->addr3)
+		return -EINVAL;
+
+	p->fds = u64_to_user_ptr(READ_ONCE(sqe->addr));
+	p->flags = READ_ONCE(sqe->pipe_flags);
+	if (p->flags & ~(O_CLOEXEC | O_NONBLOCK | O_DIRECT | O_NOTIFICATION_PIPE))
+		return -EINVAL;
+
+	p->file_slot = READ_ONCE(sqe->file_index);
+	p->nofile = rlimit(RLIMIT_NOFILE);
+	return 0;
+}
+
+static int io_pipe_fixed(struct io_kiocb *req, struct file **files,
+			 unsigned int issue_flags)
+{
+	struct io_pipe *p = io_kiocb_to_cmd(req, struct io_pipe);
+	struct io_ring_ctx *ctx = req->ctx;
+	bool alloc_slot;
+	int ret, fds[2] = { -1, -1 };
+	int slot = p->file_slot;
+
+	if (p->flags & O_CLOEXEC)
+		return -EINVAL;
+
+	alloc_slot = slot == IORING_FILE_INDEX_ALLOC;
+
+	io_ring_submit_lock(ctx, issue_flags);
+
+	ret = __io_fixed_fd_install(ctx, files[0], slot);
+	if (ret < 0)
+		goto err;
+	fds[0] = alloc_slot ? ret : slot - 1;
+	files[0] = NULL;
+
+	/*
+	 * If a specific slot is given, next one will be used for
+	 * the write side.
+	 */
+	if (!alloc_slot)
+		slot++;
+
+	ret = __io_fixed_fd_install(ctx, files[1], slot);
+	if (ret < 0)
+		goto err;
+	fds[1] = alloc_slot ? ret : slot - 1;
+	files[1] = NULL;
+
+	io_ring_submit_unlock(ctx, issue_flags);
+
+	if (!copy_to_user(p->fds, fds, sizeof(fds)))
+		return 0;
+
+	ret = -EFAULT;
+	io_ring_submit_lock(ctx, issue_flags);
+err:
+	if (fds[0] != -1)
+		io_fixed_fd_remove(ctx, fds[0]);
+	if (fds[1] != -1)
+		io_fixed_fd_remove(ctx, fds[1]);
+	io_ring_submit_unlock(ctx, issue_flags);
+	return ret;
+}
+
+static int io_pipe_fd(struct io_kiocb *req, struct file **files)
+{
+	struct io_pipe *p = io_kiocb_to_cmd(req, struct io_pipe);
+	int ret, fds[2] = { -1, -1 };
+
+	ret = __get_unused_fd_flags(p->flags, p->nofile);
+	if (ret < 0)
+		goto err;
+	fds[0] = ret;
+
+	ret = __get_unused_fd_flags(p->flags, p->nofile);
+	if (ret < 0)
+		goto err;
+	fds[1] = ret;
+
+	if (!copy_to_user(p->fds, fds, sizeof(fds))) {
+		fd_install(fds[0], files[0]);
+		fd_install(fds[1], files[1]);
+		return 0;
+	}
+	ret = -EFAULT;
+err:
+	if (fds[0] != -1)
+		put_unused_fd(fds[0]);
+	if (fds[1] != -1)
+		put_unused_fd(fds[1]);
+	return ret;
+}
+
+int io_pipe(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_pipe *p = io_kiocb_to_cmd(req, struct io_pipe);
+	struct file *files[2];
+	int ret;
+
+	ret = create_pipe_files(files, p->flags);
+	if (ret)
+		return ret;
+
+	if (!!p->file_slot)
+		ret = io_pipe_fixed(req, files, issue_flags);
+	else
+		ret = io_pipe_fd(req, files);
+
+	io_req_set_res(req, ret, 0);
+	if (!ret)
+		return IOU_COMPLETE;
+
+	req_set_fail(req);
+	if (files[0])
+		fput(files[0]);
+	if (files[1])
+		fput(files[1]);
+	return ret;
+}