Merge tag 'io_uring-7.3-20261002' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linuxgrafted

Pull io_uring fixes from Jens Axboe:

 - Fix a task_work add use-after-free with SQPOLL.

   The sqpoll thread could pop and complete the last request while
   io_req_normal_work_add() was still looking at them after the mpscq
   push.

   Use the same approach as DEFER_TASKRUN to protect from that, holding
   an RCU read lock across the add, and have exit wait for an RCU grace
   period for SQPOLL rings as well.

 - CQE32 ring fixes: correct the free entry check for 32b CQEs, zero the
   big_cqe for aux CQEs, and only post the dummy skip CQE on CQE_MIXED
   rings

 - Mark the source filter table as COW when cloning bpf filters, so
   registering another filter on the source doesn't modify the shared
   table in place

 - Initialize the task context before running the BPF loop

 - Requeue zcrx multishot receives stopped by a local resource

 - End a TX_TIMESTAMP multishot cmd when the CQ is full (lollipopkit)

* tag 'io_uring-7.3-20261002' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux:
  io_uring: fix task_work add use-after-free with SQPOLL
  io_uring/cmd_net: end TX_TIMESTAMP multishot when the CQ is full
  io_uring/zcrx: requeue multishot receives stopped by a local resource
  io_uring: initialize task context before running the BPF loop
  io_uring: zero big_cqe for aux CQEs on CQE32 rings
  io_uring: fix free entry check for 32b CQEs on CQE32 rings
  io_uring: only post the dummy skip CQE on CQE_MIXED rings
  io_uring/bpf_filter: mark source as COW when cloning filters

1 files changed, 96 insertions, 0 deletions

diff --git a/io_uring/loop.c b/io_uring/loop.c
new file mode 100644
index 000000000..3d472b782
--- /dev/null
+++ b/io_uring/loop.c
@@ -0,0 +1,96 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#include "io_uring.h"
+#include "wait.h"
+#include "loop.h"
+#include "tctx.h"
+
+static inline int io_loop_nr_cqes(const struct io_ring_ctx *ctx,
+				  const struct iou_loop_params *lp)
+{
+	return lp->cq_wait_idx - READ_ONCE(ctx->rings->cq.tail);
+}
+
+static inline void io_loop_wait_start(struct io_ring_ctx *ctx, unsigned nr_wait)
+{
+	atomic_set(&ctx->cq_wait_nr, nr_wait);
+	set_current_state(TASK_INTERRUPTIBLE);
+}
+
+static inline void io_loop_wait_finish(struct io_ring_ctx *ctx)
+{
+	__set_current_state(TASK_RUNNING);
+	atomic_set(&ctx->cq_wait_nr, IO_CQ_WAKE_INIT);
+}
+
+static void io_loop_wait(struct io_ring_ctx *ctx, struct iou_loop_params *lp,
+			 unsigned nr_wait)
+{
+	io_loop_wait_start(ctx, nr_wait);
+
+	if (unlikely(io_local_work_pending(ctx) ||
+		     io_loop_nr_cqes(ctx, lp) <= 0) ||
+		     READ_ONCE(ctx->check_cq)) {
+		io_loop_wait_finish(ctx);
+		return;
+	}
+
+	mutex_unlock(&ctx->uring_lock);
+	schedule();
+	io_loop_wait_finish(ctx);
+	mutex_lock(&ctx->uring_lock);
+}
+
+static int __io_run_loop(struct io_ring_ctx *ctx)
+{
+	struct iou_loop_params lp = {};
+
+	while (true) {
+		int nr_wait, step_res;
+
+		if (unlikely(!ctx->loop_step))
+			return -EFAULT;
+
+		step_res = ctx->loop_step(io_loop_mangle_ctx(ctx), &lp);
+		if (step_res == IOU_LOOP_STOP)
+			break;
+		if (step_res != IOU_LOOP_CONTINUE)
+			return -EINVAL;
+
+		nr_wait = io_loop_nr_cqes(ctx, &lp);
+		if (nr_wait > 0)
+			io_loop_wait(ctx, &lp, nr_wait);
+		else
+			nr_wait = 0;
+
+		if (task_work_pending(current)) {
+			mutex_unlock(&ctx->uring_lock);
+			io_run_task_work();
+			mutex_lock(&ctx->uring_lock);
+		}
+		if (unlikely(task_sigpending(current)))
+			return -EINTR;
+		io_run_local_work_locked(ctx, nr_wait);
+
+		if (READ_ONCE(ctx->check_cq) & BIT(IO_CHECK_CQ_OVERFLOW_BIT))
+			io_cqring_overflow_flush_locked(ctx);
+	}
+
+	return 0;
+}
+
+int io_run_loop(struct io_ring_ctx *ctx)
+{
+	int ret;
+
+	ret = io_uring_add_tctx_node(ctx);
+	if (unlikely(ret))
+		return ret;
+
+	if (!io_allowed_run_tw(ctx))
+		return -EEXIST;
+
+	mutex_lock(&ctx->uring_lock);
+	ret = __io_run_loop(ctx);
+	mutex_unlock(&ctx->uring_lock);
+	return ret;
+}