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, 755 insertions, 0 deletions

diff --git a/io_uring/timeout.c b/io_uring/timeout.c
new file mode 100644
index 000000000..c4dd26cf3
--- /dev/null
+++ b/io_uring/timeout.c
@@ -0,0 +1,755 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/file.h>
+#include <linux/io_uring.h>
+#include <linux/time_namespace.h>
+
+#include <trace/events/io_uring.h>
+
+#include <uapi/linux/io_uring.h>
+
+#include "io_uring.h"
+#include "refs.h"
+#include "cancel.h"
+#include "timeout.h"
+
+struct io_timeout {
+	struct file			*file;
+	u32				off;
+	u32				target_seq;
+	u32				repeats;
+	struct list_head		list;
+	/* head of the link, used by linked timeouts only */
+	struct io_kiocb			*head;
+	/* for linked completions */
+	struct io_kiocb			*prev;
+};
+
+struct io_timeout_rem {
+	struct file			*file;
+	u64				addr;
+
+	/* timeout update */
+	ktime_t				time;
+	u32				flags;
+	bool				ltimeout;
+};
+
+static clockid_t io_flags_to_clock(unsigned flags)
+{
+	switch (flags & IORING_TIMEOUT_CLOCK_MASK) {
+	case IORING_TIMEOUT_BOOTTIME:
+		return CLOCK_BOOTTIME;
+	case IORING_TIMEOUT_REALTIME:
+		return CLOCK_REALTIME;
+	default:
+		/* can't happen, vetted at prep time */
+		WARN_ON_ONCE(1);
+		fallthrough;
+	case 0:
+		return CLOCK_MONOTONIC;
+	}
+}
+
+static int io_parse_user_time(ktime_t *time, u64 arg, unsigned flags)
+{
+	struct timespec64 ts;
+
+	if (flags & IORING_TIMEOUT_IMMEDIATE_ARG) {
+		*time = ns_to_ktime(arg);
+		if (*time < 0)
+			return -EINVAL;
+		goto out;
+	}
+
+	if (get_timespec64(&ts, u64_to_user_ptr(arg)))
+		return -EFAULT;
+	if (ts.tv_sec < 0 || ts.tv_nsec < 0)
+		return -EINVAL;
+	*time = timespec64_to_ktime(ts);
+out:
+	if (flags & IORING_TIMEOUT_ABS)
+		*time = timens_ktime_to_host(io_flags_to_clock(flags), *time);
+	return 0;
+}
+
+static struct io_kiocb *__io_disarm_linked_timeout(struct io_kiocb *req,
+						   struct io_kiocb *link);
+
+static inline bool io_is_timeout_noseq(struct io_kiocb *req)
+{
+	struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
+	struct io_timeout_data *data = req->async_data;
+
+	return !timeout->off || data->flags & IORING_TIMEOUT_MULTISHOT;
+}
+
+static inline void io_put_req(struct io_kiocb *req)
+{
+	if (req_ref_put_and_test(req)) {
+		io_queue_next(req);
+		io_free_req(req);
+	}
+}
+
+static inline bool io_timeout_finish(struct io_timeout *timeout,
+				     struct io_timeout_data *data)
+{
+	if (!(data->flags & IORING_TIMEOUT_MULTISHOT))
+		return true;
+
+	if (!timeout->off || (timeout->repeats && --timeout->repeats))
+		return false;
+
+	return true;
+}
+
+static enum hrtimer_restart io_timeout_fn(struct hrtimer *timer);
+
+static void io_timeout_complete(struct io_tw_req tw_req, io_tw_token_t tw)
+{
+	struct io_kiocb *req = tw_req.req;
+	struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
+	struct io_timeout_data *data = req->async_data;
+	struct io_ring_ctx *ctx = req->ctx;
+
+	if (!io_timeout_finish(timeout, data)) {
+		if (io_req_post_cqe(req, -ETIME, IORING_CQE_F_MORE)) {
+			/* re-arm timer */
+			raw_spin_lock_irq(&ctx->timeout_lock);
+			list_add(&timeout->list, ctx->timeout_list.prev);
+			hrtimer_start(&data->timer, data->time, data->mode);
+			raw_spin_unlock_irq(&ctx->timeout_lock);
+			return;
+		}
+	}
+
+	io_req_task_complete(tw_req, tw);
+}
+
+static __cold bool io_flush_killed_timeouts(struct list_head *list, int err)
+{
+	if (list_empty(list))
+		return false;
+
+	while (!list_empty(list)) {
+		struct io_timeout *timeout;
+		struct io_kiocb *req;
+
+		timeout = list_first_entry(list, struct io_timeout, list);
+		list_del_init(&timeout->list);
+		req = cmd_to_io_kiocb(timeout);
+		if (err)
+			req_set_fail(req);
+		io_req_queue_tw_complete(req, err);
+	}
+
+	return true;
+}
+
+static void io_kill_timeout(struct io_kiocb *req, struct list_head *list)
+	__must_hold(&req->ctx->timeout_lock)
+{
+	struct io_timeout_data *io = req->async_data;
+
+	if (hrtimer_try_to_cancel(&io->timer) != -1) {
+		struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
+
+		atomic_set(&req->ctx->cq_timeouts,
+			atomic_read(&req->ctx->cq_timeouts) + 1);
+		list_move_tail(&timeout->list, list);
+	}
+}
+
+__cold void io_flush_timeouts(struct io_ring_ctx *ctx)
+{
+	struct io_timeout *timeout, *tmp;
+	LIST_HEAD(list);
+	u32 seq;
+
+	raw_spin_lock_irq(&ctx->timeout_lock);
+	seq = READ_ONCE(ctx->cached_cq_tail) - atomic_read(&ctx->cq_timeouts);
+
+	list_for_each_entry_safe(timeout, tmp, &ctx->timeout_list, list) {
+		struct io_kiocb *req = cmd_to_io_kiocb(timeout);
+		u32 events_needed, events_got;
+
+		if (io_is_timeout_noseq(req))
+			break;
+
+		/*
+		 * Since seq can easily wrap around over time, subtract
+		 * the last seq at which timeouts were flushed before comparing.
+		 * Assuming not more than 2^31-1 events have happened since,
+		 * these subtractions won't have wrapped, so we can check if
+		 * target is in [last_seq, current_seq] by comparing the two.
+		 */
+		events_needed = timeout->target_seq - ctx->cq_last_tm_flush;
+		events_got = seq - ctx->cq_last_tm_flush;
+		if (events_got < events_needed)
+			break;
+
+		io_kill_timeout(req, &list);
+	}
+	ctx->cq_last_tm_flush = seq;
+	raw_spin_unlock_irq(&ctx->timeout_lock);
+	io_flush_killed_timeouts(&list, 0);
+}
+
+static void io_req_tw_fail_links(struct io_tw_req tw_req, io_tw_token_t tw)
+{
+	struct io_kiocb *link = tw_req.req;
+
+	io_tw_lock(link->ctx, tw);
+	while (link) {
+		struct io_kiocb *nxt = link->link;
+		long res = -ECANCELED;
+
+		if (link->flags & REQ_F_FAIL)
+			res = link->cqe.res;
+		link->link = NULL;
+		io_req_set_res(link, res, 0);
+		io_req_task_complete((struct io_tw_req){link}, tw);
+		link = nxt;
+	}
+}
+
+static void io_fail_links(struct io_kiocb *req)
+	__must_hold(&req->ctx->completion_lock)
+{
+	struct io_kiocb *link = req->link;
+	bool ignore_cqes = req->flags & REQ_F_SKIP_LINK_CQES;
+
+	if (!link)
+		return;
+
+	while (link) {
+		if (ignore_cqes)
+			link->flags |= REQ_F_CQE_SKIP;
+		else
+			link->flags &= ~REQ_F_CQE_SKIP;
+		trace_io_uring_fail_link(req, link);
+		link = link->link;
+	}
+
+	link = req->link;
+	link->io_task_work.func = io_req_tw_fail_links;
+	io_req_task_work_add(link);
+	req->link = NULL;
+}
+
+static inline void io_remove_next_linked(struct io_kiocb *req)
+{
+	struct io_kiocb *nxt = req->link;
+
+	req->link = nxt->link;
+	nxt->link = NULL;
+}
+
+void io_disarm_next(struct io_kiocb *req)
+	__must_hold(&req->ctx->completion_lock)
+{
+	struct io_kiocb *link = NULL;
+
+	if (req->flags & REQ_F_ARM_LTIMEOUT) {
+		link = req->link;
+		req->flags &= ~REQ_F_ARM_LTIMEOUT;
+		if (link && link->opcode == IORING_OP_LINK_TIMEOUT) {
+			io_remove_next_linked(req);
+			io_req_queue_tw_complete(link, -ECANCELED);
+		}
+	} else if (req->flags & REQ_F_LINK_TIMEOUT) {
+		struct io_ring_ctx *ctx = req->ctx;
+
+		raw_spin_lock_irq(&ctx->timeout_lock);
+		if (req->link && req->link->opcode == IORING_OP_LINK_TIMEOUT)
+			link = __io_disarm_linked_timeout(req, req->link);
+
+		raw_spin_unlock_irq(&ctx->timeout_lock);
+		if (link)
+			io_req_queue_tw_complete(link, -ECANCELED);
+	}
+	if (unlikely((req->flags & REQ_F_FAIL) &&
+		     !(req->flags & REQ_F_HARDLINK)))
+		io_fail_links(req);
+}
+
+static struct io_kiocb *__io_disarm_linked_timeout(struct io_kiocb *req,
+						   struct io_kiocb *link)
+	__must_hold(&req->ctx->completion_lock)
+	__must_hold(&req->ctx->timeout_lock)
+{
+	struct io_timeout_data *io = link->async_data;
+	struct io_timeout *timeout = io_kiocb_to_cmd(link, struct io_timeout);
+
+	io_remove_next_linked(req);
+
+	/* If this is NULL, then timer already claimed it and will complete it */
+	if (!timeout->head)
+		return NULL;
+	timeout->head = NULL;
+	if (hrtimer_try_to_cancel(&io->timer) != -1) {
+		list_del(&timeout->list);
+		return link;
+	}
+
+	return NULL;
+}
+
+static enum hrtimer_restart io_timeout_fn(struct hrtimer *timer)
+{
+	struct io_timeout_data *data = container_of(timer,
+						struct io_timeout_data, timer);
+	struct io_kiocb *req = data->req;
+	struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
+	struct io_ring_ctx *ctx = req->ctx;
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&ctx->timeout_lock, flags);
+	list_del_init(&timeout->list);
+	atomic_set(&ctx->cq_timeouts,
+		atomic_read(&ctx->cq_timeouts) + 1);
+	raw_spin_unlock_irqrestore(&ctx->timeout_lock, flags);
+
+	if (!(data->flags & IORING_TIMEOUT_ETIME_SUCCESS))
+		req_set_fail(req);
+
+	io_req_set_res(req, -ETIME, 0);
+	req->io_task_work.func = io_timeout_complete;
+	io_req_task_work_add(req);
+	return HRTIMER_NORESTART;
+}
+
+static struct io_kiocb *io_timeout_extract(struct io_ring_ctx *ctx,
+					   struct io_cancel_data *cd)
+	__must_hold(&ctx->timeout_lock)
+{
+	struct io_timeout *timeout;
+	struct io_timeout_data *io;
+	struct io_kiocb *req = NULL;
+
+	list_for_each_entry(timeout, &ctx->timeout_list, list) {
+		struct io_kiocb *tmp = cmd_to_io_kiocb(timeout);
+
+		if (io_cancel_req_match(tmp, cd)) {
+			req = tmp;
+			break;
+		}
+	}
+	if (!req)
+		return ERR_PTR(-ENOENT);
+
+	io = req->async_data;
+	if (hrtimer_try_to_cancel(&io->timer) == -1)
+		return ERR_PTR(-EALREADY);
+	timeout = io_kiocb_to_cmd(req, struct io_timeout);
+	list_del_init(&timeout->list);
+	return req;
+}
+
+int io_timeout_cancel(struct io_ring_ctx *ctx, struct io_cancel_data *cd)
+	__must_hold(&ctx->completion_lock)
+{
+	struct io_kiocb *req;
+
+	raw_spin_lock_irq(&ctx->timeout_lock);
+	req = io_timeout_extract(ctx, cd);
+	raw_spin_unlock_irq(&ctx->timeout_lock);
+
+	if (IS_ERR(req))
+		return PTR_ERR(req);
+	io_req_task_queue_fail(req, -ECANCELED);
+	return 0;
+}
+
+static void io_req_task_link_timeout(struct io_tw_req tw_req, io_tw_token_t tw)
+{
+	struct io_kiocb *req = tw_req.req;
+	struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
+	struct io_kiocb *prev = timeout->prev;
+	int ret;
+
+	if (prev) {
+		/*
+		 * splice the linked timeout out of prev's chain if the regular
+		 * completion path didn't already do it.
+		 */
+		if (prev->link == req)
+			prev->link = req->link;
+		req->link = NULL;
+
+		if (!tw.cancel) {
+			struct io_cancel_data cd = {
+				.ctx		= req->ctx,
+				.data		= prev->cqe.user_data,
+			};
+
+			ret = io_try_cancel(req->tctx, &cd, 0);
+		} else {
+			ret = -ECANCELED;
+		}
+		io_req_set_res(req, ret ?: -ETIME, 0);
+		io_req_task_complete(tw_req, tw);
+		io_put_req(prev);
+	} else {
+		io_req_set_res(req, -ETIME, 0);
+		io_req_task_complete(tw_req, tw);
+	}
+}
+
+static enum hrtimer_restart io_link_timeout_fn(struct hrtimer *timer)
+{
+	struct io_timeout_data *data = container_of(timer,
+						struct io_timeout_data, timer);
+	struct io_kiocb *prev, *req = data->req;
+	struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
+	struct io_ring_ctx *ctx = req->ctx;
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&ctx->timeout_lock, flags);
+	prev = timeout->head;
+	timeout->head = NULL;
+
+	/*
+	 * We don't expect the list to be empty, that will only happen if we
+	 * race with the completion of the linked work. Splice of prev is
+	 * done in io_req_task_link_timeout(), if needed.
+	 */
+	if (prev) {
+		if (!req_ref_inc_not_zero(prev)) {
+			io_remove_next_linked(prev);
+			prev = NULL;
+		}
+	}
+	list_del(&timeout->list);
+	timeout->prev = prev;
+	raw_spin_unlock_irqrestore(&ctx->timeout_lock, flags);
+
+	req->io_task_work.func = io_req_task_link_timeout;
+	io_req_task_work_add(req);
+	return HRTIMER_NORESTART;
+}
+
+static clockid_t io_timeout_get_clock(struct io_timeout_data *data)
+{
+	return io_flags_to_clock(data->flags);
+}
+
+static int io_linked_timeout_update(struct io_ring_ctx *ctx, __u64 user_data,
+				    ktime_t ts, enum hrtimer_mode mode)
+	__must_hold(&ctx->timeout_lock)
+{
+	struct io_timeout_data *io;
+	struct io_timeout *timeout;
+	struct io_kiocb *req = NULL;
+
+	list_for_each_entry(timeout, &ctx->ltimeout_list, list) {
+		struct io_kiocb *tmp = cmd_to_io_kiocb(timeout);
+
+		if (user_data == tmp->cqe.user_data) {
+			req = tmp;
+			break;
+		}
+	}
+	if (!req)
+		return -ENOENT;
+
+	io = req->async_data;
+	if (hrtimer_try_to_cancel(&io->timer) == -1)
+		return -EALREADY;
+	hrtimer_setup(&io->timer, io_link_timeout_fn, io_timeout_get_clock(io), mode);
+	hrtimer_start(&io->timer, ts, mode);
+	return 0;
+}
+
+static int io_timeout_update(struct io_ring_ctx *ctx, __u64 user_data,
+			     ktime_t time, enum hrtimer_mode mode)
+	__must_hold(&ctx->timeout_lock)
+{
+	struct io_cancel_data cd = { .ctx = ctx, .data = user_data, };
+	struct io_kiocb *req = io_timeout_extract(ctx, &cd);
+	struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
+	struct io_timeout_data *data;
+
+	if (IS_ERR(req))
+		return PTR_ERR(req);
+
+	timeout->off = 0; /* noseq */
+	data = req->async_data;
+	data->time = time;
+
+	list_add_tail(&timeout->list, &ctx->timeout_list);
+	hrtimer_setup(&data->timer, io_timeout_fn, io_timeout_get_clock(data), mode);
+	hrtimer_start(&data->timer, data->time, mode);
+	return 0;
+}
+
+int io_timeout_remove_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+	struct io_timeout_rem *tr = io_kiocb_to_cmd(req, struct io_timeout_rem);
+	int ret;
+
+	if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT)))
+		return -EINVAL;
+	if (sqe->addr3 || sqe->__pad2[0])
+		return -EINVAL;
+	if (sqe->buf_index || sqe->len || sqe->splice_fd_in)
+		return -EINVAL;
+
+	tr->ltimeout = false;
+	tr->addr = READ_ONCE(sqe->addr);
+	tr->flags = READ_ONCE(sqe->timeout_flags);
+	if (tr->flags & IORING_TIMEOUT_UPDATE_MASK) {
+		if (hweight32(tr->flags & IORING_TIMEOUT_CLOCK_MASK) > 1)
+			return -EINVAL;
+		if (tr->flags & IORING_LINK_TIMEOUT_UPDATE)
+			tr->ltimeout = true;
+		if (tr->flags & ~(IORING_TIMEOUT_UPDATE_MASK |
+				  IORING_TIMEOUT_ABS |
+				  IORING_TIMEOUT_IMMEDIATE_ARG))
+			return -EINVAL;
+		ret = io_parse_user_time(&tr->time, READ_ONCE(sqe->addr2), tr->flags);
+		if (ret)
+			return ret;
+	} else if (tr->flags) {
+		/* timeout removal doesn't support flags */
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static inline enum hrtimer_mode io_translate_timeout_mode(unsigned int flags)
+{
+	return (flags & IORING_TIMEOUT_ABS) ? HRTIMER_MODE_ABS
+					    : HRTIMER_MODE_REL;
+}
+
+/*
+ * Remove or update an existing timeout command
+ */
+int io_timeout_remove(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_timeout_rem *tr = io_kiocb_to_cmd(req, struct io_timeout_rem);
+	struct io_ring_ctx *ctx = req->ctx;
+	int ret;
+
+	if (!(tr->flags & IORING_TIMEOUT_UPDATE)) {
+		struct io_cancel_data cd = { .ctx = ctx, .data = tr->addr, };
+
+		spin_lock(&ctx->completion_lock);
+		ret = io_timeout_cancel(ctx, &cd);
+		spin_unlock(&ctx->completion_lock);
+	} else {
+		enum hrtimer_mode mode = io_translate_timeout_mode(tr->flags);
+
+		raw_spin_lock_irq(&ctx->timeout_lock);
+		if (tr->ltimeout)
+			ret = io_linked_timeout_update(ctx, tr->addr, tr->time, mode);
+		else
+			ret = io_timeout_update(ctx, tr->addr, tr->time, mode);
+		raw_spin_unlock_irq(&ctx->timeout_lock);
+	}
+
+	if (ret < 0)
+		req_set_fail(req);
+	io_req_set_res(req, ret, 0);
+	return IOU_COMPLETE;
+}
+
+static int __io_timeout_prep(struct io_kiocb *req,
+			     const struct io_uring_sqe *sqe,
+			     bool is_timeout_link)
+{
+	struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
+	struct io_timeout_data *data;
+	unsigned flags;
+	u32 off = READ_ONCE(sqe->off);
+	int ret;
+
+	if (sqe->addr3 || sqe->__pad2[0])
+		return -EINVAL;
+	if (sqe->buf_index || sqe->len != 1 || sqe->splice_fd_in)
+		return -EINVAL;
+	if (off && is_timeout_link)
+		return -EINVAL;
+	flags = READ_ONCE(sqe->timeout_flags);
+	if (flags & ~(IORING_TIMEOUT_ABS | IORING_TIMEOUT_CLOCK_MASK |
+		      IORING_TIMEOUT_ETIME_SUCCESS |
+		      IORING_TIMEOUT_MULTISHOT |
+		      IORING_TIMEOUT_IMMEDIATE_ARG))
+		return -EINVAL;
+	/* more than one clock specified is invalid, obviously */
+	if (hweight32(flags & IORING_TIMEOUT_CLOCK_MASK) > 1)
+		return -EINVAL;
+	/* multishot requests only make sense with rel values */
+	if (!(~flags & (IORING_TIMEOUT_MULTISHOT | IORING_TIMEOUT_ABS)))
+		return -EINVAL;
+
+	INIT_LIST_HEAD(&timeout->list);
+	timeout->off = off;
+	if (unlikely(off && !(req->ctx->int_flags & IO_RING_F_OFF_TIMEOUT_USED)))
+		req->ctx->int_flags |= IO_RING_F_OFF_TIMEOUT_USED;
+	/*
+	 * for multishot reqs w/ fixed nr of repeats, repeats tracks the
+	 * remaining nr
+	 */
+	timeout->repeats = 0;
+	if ((flags & IORING_TIMEOUT_MULTISHOT) && off > 0)
+		timeout->repeats = off;
+
+	if (WARN_ON_ONCE(req_has_async_data(req)))
+		return -EFAULT;
+	data = io_uring_alloc_async_data(NULL, req);
+	if (!data)
+		return -ENOMEM;
+	data->req = req;
+	data->flags = flags;
+
+	ret = io_parse_user_time(&data->time, READ_ONCE(sqe->addr), flags);
+	if (ret)
+		return ret;
+
+	data->mode = io_translate_timeout_mode(flags);
+
+	if (is_timeout_link) {
+		struct io_submit_link *link = &req->ctx->submit_state.link;
+
+		if (!link->head)
+			return -EINVAL;
+		if (link->last->opcode == IORING_OP_LINK_TIMEOUT)
+			return -EINVAL;
+		timeout->head = link->last;
+		link->last->flags |= REQ_F_ARM_LTIMEOUT;
+		hrtimer_setup(&data->timer, io_link_timeout_fn, io_timeout_get_clock(data),
+			      data->mode);
+	} else {
+		hrtimer_setup(&data->timer, io_timeout_fn, io_timeout_get_clock(data), data->mode);
+	}
+	return 0;
+}
+
+int io_timeout_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+	return __io_timeout_prep(req, sqe, false);
+}
+
+int io_link_timeout_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+	return __io_timeout_prep(req, sqe, true);
+}
+
+int io_timeout(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
+	struct io_ring_ctx *ctx = req->ctx;
+	struct io_timeout_data *data = req->async_data;
+	struct list_head *entry;
+	u32 tail, off = timeout->off;
+
+	raw_spin_lock_irq(&ctx->timeout_lock);
+
+	/*
+	 * sqe->off holds how many events that need to occur for this
+	 * timeout event to be satisfied. If it isn't set, then this is
+	 * a pure timeout request, sequence isn't used.
+	 */
+	if (io_is_timeout_noseq(req)) {
+		entry = ctx->timeout_list.prev;
+		goto add;
+	}
+
+	tail = data_race(ctx->cached_cq_tail) - atomic_read(&ctx->cq_timeouts);
+	timeout->target_seq = tail + off;
+
+	/* Update the last seq here in case io_flush_timeouts() hasn't.
+	 * This is safe because ->completion_lock is held, and submissions
+	 * and completions are never mixed in the same ->completion_lock section.
+	 */
+	ctx->cq_last_tm_flush = tail;
+
+	/*
+	 * Insertion sort, ensuring the first entry in the list is always
+	 * the one we need first.
+	 */
+	list_for_each_prev(entry, &ctx->timeout_list) {
+		struct io_timeout *nextt = list_entry(entry, struct io_timeout, list);
+		struct io_kiocb *nxt = cmd_to_io_kiocb(nextt);
+
+		if (io_is_timeout_noseq(nxt))
+			continue;
+		/* nxt.seq is behind @tail, otherwise would've been completed */
+		if (off >= nextt->target_seq - tail)
+			break;
+	}
+add:
+	list_add(&timeout->list, entry);
+	hrtimer_start(&data->timer, data->time, data->mode);
+	raw_spin_unlock_irq(&ctx->timeout_lock);
+	return IOU_ISSUE_SKIP_COMPLETE;
+}
+
+void io_queue_linked_timeout(struct io_kiocb *req)
+{
+	struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
+	struct io_ring_ctx *ctx = req->ctx;
+
+	raw_spin_lock_irq(&ctx->timeout_lock);
+	/*
+	 * If the back reference is NULL, then our linked request finished
+	 * before we got a chance to setup the timer
+	 */
+	if (timeout->head) {
+		struct io_timeout_data *data = req->async_data;
+
+		hrtimer_start(&data->timer, data->time, data->mode);
+		list_add_tail(&timeout->list, &ctx->ltimeout_list);
+	}
+	raw_spin_unlock_irq(&ctx->timeout_lock);
+	/* drop submission reference */
+	io_put_req(req);
+}
+
+static bool io_match_task(struct io_kiocb *head, struct io_uring_task *tctx,
+			  bool cancel_all)
+	__must_hold(&head->ctx->timeout_lock)
+{
+	struct io_kiocb *req;
+
+	if (tctx && head->tctx != tctx)
+		return false;
+	if (cancel_all)
+		return true;
+
+	io_for_each_link(req, head) {
+		if (req->flags & REQ_F_INFLIGHT)
+			return true;
+	}
+	return false;
+}
+
+/* Returns true if we found and killed one or more timeouts */
+__cold bool io_kill_timeouts(struct io_ring_ctx *ctx, struct io_uring_task *tctx,
+			     bool cancel_all)
+{
+	struct io_timeout *timeout, *tmp;
+	LIST_HEAD(list);
+
+	/*
+	 * completion_lock is needed for io_match_task(). Take it before
+	 * timeout_lockfirst to keep locking ordering.
+	 */
+	spin_lock(&ctx->completion_lock);
+	raw_spin_lock_irq(&ctx->timeout_lock);
+	list_for_each_entry_safe(timeout, tmp, &ctx->timeout_list, list) {
+		struct io_kiocb *req = cmd_to_io_kiocb(timeout);
+
+		if (io_match_task(req, tctx, cancel_all))
+			io_kill_timeout(req, &list);
+	}
+	raw_spin_unlock_irq(&ctx->timeout_lock);
+	spin_unlock(&ctx->completion_lock);
+
+	return io_flush_killed_timeouts(&list, -ECANCELED);
+}