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, 197 insertions, 0 deletions

diff --git a/samples/livepatch/livepatch-callbacks-demo.c b/samples/livepatch/livepatch-callbacks-demo.c
new file mode 100644
index 000000000..9e69d9cae
--- /dev/null
+++ b/samples/livepatch/livepatch-callbacks-demo.c
@@ -0,0 +1,197 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2017 Joe Lawrence <joe.lawrence@redhat.com>
+ */
+
+/*
+ * livepatch-callbacks-demo.c - (un)patching callbacks livepatch demo
+ *
+ *
+ * Purpose
+ * -------
+ *
+ * Demonstration of registering livepatch (un)patching callbacks.
+ *
+ *
+ * Usage
+ * -----
+ *
+ * Step 1 - load the simple module
+ *
+ *   insmod samples/livepatch/livepatch-callbacks-mod.ko
+ *
+ *
+ * Step 2 - load the demonstration livepatch (with callbacks)
+ *
+ *   insmod samples/livepatch/livepatch-callbacks-demo.ko
+ *
+ *
+ * Step 3 - cleanup
+ *
+ *   echo 0 > /sys/kernel/livepatch/livepatch_callbacks_demo/enabled
+ *   rmmod livepatch_callbacks_demo
+ *   rmmod livepatch_callbacks_mod
+ *
+ * Watch dmesg output to see livepatch enablement, callback execution
+ * and patching operations for both vmlinux and module targets.
+ *
+ * NOTE: swap the insmod order of livepatch-callbacks-mod.ko and
+ *       livepatch-callbacks-demo.ko to observe what happens when a
+ *       target module is loaded after a livepatch with callbacks.
+ *
+ * NOTE: 'pre_patch_ret' is a module parameter that sets the pre-patch
+ *       callback return status.  Try setting up a non-zero status
+ *       such as -19 (-ENODEV):
+ *
+ *       # Load demo livepatch, vmlinux is patched
+ *       insmod samples/livepatch/livepatch-callbacks-demo.ko
+ *
+ *       # Setup next pre-patch callback to return -ENODEV
+ *       echo -19 > /sys/module/livepatch_callbacks_demo/parameters/pre_patch_ret
+ *
+ *       # Module loader refuses to load the target module
+ *       insmod samples/livepatch/livepatch-callbacks-mod.ko
+ *       insmod: ERROR: could not insert module samples/livepatch/livepatch-callbacks-mod.ko: No such device
+ *
+ * NOTE: There is a second target module,
+ *       livepatch-callbacks-busymod.ko, available for experimenting
+ *       with livepatch (un)patch callbacks.  This module contains
+ *       a 'sleep_secs' parameter that parks the module on one of the
+ *       functions that the livepatch demo module wants to patch.
+ *       Modifying this value and tweaking the order of module loads can
+ *       effectively demonstrate stalled patch transitions:
+ *
+ *       # Load a target module, let it park on 'busymod_work_func' for
+ *       # thirty seconds
+ *       insmod samples/livepatch/livepatch-callbacks-busymod.ko sleep_secs=30
+ *
+ *       # Meanwhile load the livepatch
+ *       insmod samples/livepatch/livepatch-callbacks-demo.ko
+ *
+ *       # ... then load and unload another target module while the
+ *       # transition is in progress
+ *       insmod samples/livepatch/livepatch-callbacks-mod.ko
+ *       rmmod samples/livepatch/livepatch-callbacks-mod.ko
+ *
+ *       # Finally cleanup
+ *       echo 0 > /sys/kernel/livepatch/livepatch_callbacks_demo/enabled
+ *       rmmod samples/livepatch/livepatch-callbacks-demo.ko
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/livepatch.h>
+
+static int pre_patch_ret;
+module_param(pre_patch_ret, int, 0644);
+MODULE_PARM_DESC(pre_patch_ret, "pre_patch_ret (default=0)");
+
+static const char *const module_state[] = {
+	[MODULE_STATE_LIVE]	= "[MODULE_STATE_LIVE] Normal state",
+	[MODULE_STATE_COMING]	= "[MODULE_STATE_COMING] Full formed, running module_init",
+	[MODULE_STATE_GOING]	= "[MODULE_STATE_GOING] Going away",
+	[MODULE_STATE_UNFORMED]	= "[MODULE_STATE_UNFORMED] Still setting it up",
+};
+
+static void callback_info(const char *callback, struct klp_object *obj)
+{
+	if (obj->mod)
+		pr_info("%s: %s -> %s\n", callback, obj->mod->name,
+			module_state[obj->mod->state]);
+	else
+		pr_info("%s: vmlinux\n", callback);
+}
+
+/* Executed on object patching (ie, patch enablement) */
+static int pre_patch_callback(struct klp_object *obj)
+{
+	callback_info(__func__, obj);
+	return pre_patch_ret;
+}
+
+/* Executed on object unpatching (ie, patch disablement) */
+static void post_patch_callback(struct klp_object *obj)
+{
+	callback_info(__func__, obj);
+}
+
+/* Executed on object unpatching (ie, patch disablement) */
+static void pre_unpatch_callback(struct klp_object *obj)
+{
+	callback_info(__func__, obj);
+}
+
+/* Executed on object unpatching (ie, patch disablement) */
+static void post_unpatch_callback(struct klp_object *obj)
+{
+	callback_info(__func__, obj);
+}
+
+static void patched_work_func(struct work_struct *work)
+{
+	pr_info("%s\n", __func__);
+}
+
+static struct klp_func no_funcs[] = {
+	{ }
+};
+
+static struct klp_func busymod_funcs[] = {
+	{
+		.old_name = "busymod_work_func",
+		.new_func = patched_work_func,
+	}, { }
+};
+
+static struct klp_object objs[] = {
+	{
+		.name = NULL,	/* vmlinux */
+		.funcs = no_funcs,
+		.callbacks = {
+			.pre_patch = pre_patch_callback,
+			.post_patch = post_patch_callback,
+			.pre_unpatch = pre_unpatch_callback,
+			.post_unpatch = post_unpatch_callback,
+		},
+	},	{
+		.name = "livepatch_callbacks_mod",
+		.funcs = no_funcs,
+		.callbacks = {
+			.pre_patch = pre_patch_callback,
+			.post_patch = post_patch_callback,
+			.pre_unpatch = pre_unpatch_callback,
+			.post_unpatch = post_unpatch_callback,
+		},
+	},	{
+		.name = "livepatch_callbacks_busymod",
+		.funcs = busymod_funcs,
+		.callbacks = {
+			.pre_patch = pre_patch_callback,
+			.post_patch = post_patch_callback,
+			.pre_unpatch = pre_unpatch_callback,
+			.post_unpatch = post_unpatch_callback,
+		},
+	}, { }
+};
+
+static struct klp_patch patch = {
+	.mod = THIS_MODULE,
+	.objs = objs,
+};
+
+static int livepatch_callbacks_demo_init(void)
+{
+	return klp_enable_patch(&patch);
+}
+
+static void livepatch_callbacks_demo_exit(void)
+{
+}
+
+module_init(livepatch_callbacks_demo_init);
+module_exit(livepatch_callbacks_demo_exit);
+MODULE_DESCRIPTION("Live patching demo for (un)patching callbacks");
+MODULE_LICENSE("GPL");
+MODULE_INFO(livepatch, "Y");