Merge branches 'expcb.2026.07.24a', 'misc.2026.07.30a', 'rcu-tasks.2026.07.30a', 'srcu.2026.08.11a' and 'torture.2026.08.14a' into HEADgrafted

Changes:

Make expedited grace periods expedite normal RCU callbacks

Miscellaneous fixes:
 * Improve diagnostic output with character task states.
 * Mark accesses to inform KCSAN of concurrency design.
 * Move from kmalloc() to kmalloc_obj().
 * Documentation updates.
 * Improve handling of RCU deferred quiescent states.
 * Clean up unused function arguments and structure fields.
 * Reduce show_rcu_gp_kthreads() stack space.

Tasks RCU updates:
 * Clean up after SRCU re-implementation of Tasks Trace RCU.
 * Mark accesses to inform KCSAN of concurrency design.
 * Add ->lazy_timer status to diagnostic output.
 * Remove an unnecessary memory barrier.
 * Fix a data race, courtesy of KCSAN.
 * Documentation updates.
 * Convert cond_resched_tasks_rcu_qs() from macro to static inline
   function.

SRCU updates:
 * Add Rust helpers for SRCU.
 * Avoid losing queued work at cleanup_srcu_struct() time.

Torture-test updates:
 * Preparation work for immediate RCU priority deboosting.
 * Test RCU readers from real interrupt handlers (as opposed to softirq).
 * Simplify code through use of cpumask_next_wrap().
 * Improve diagnostic output with character task states.
 * Add rcutorture.nwriters parameter to allow lightweight stall testing,
   and rcutorture.stall_only to make doing so easier.
 * Test an RCU Tasks Trace grace period implying an RCU grace period.
 * Make RCU Tasks Trace torturing track reader batches.
 * Fix a data race, courtesy of KCSAN.
 * Plug a shuffle_tmp_mask memory leak on kthread spawn failure.

3 files changed, 167 insertions, 0 deletions

diff --git a/Documentation/gpu/dp-mst/topology-figure-1.dot b/Documentation/gpu/dp-mst/topology-figure-1.dot
new file mode 100644
index 000000000..157e17c7e
--- /dev/null
+++ b/Documentation/gpu/dp-mst/topology-figure-1.dot
@@ -0,0 +1,52 @@
+digraph T {
+    /* Make sure our payloads are always drawn below the driver node */
+    subgraph cluster_driver {
+        fillcolor = grey;
+        style = filled;
+        driver -> {payload1, payload2} [dir=none];
+    }
+
+    /* Driver malloc references */
+    edge [style=dashed];
+    driver -> port1;
+    driver -> port2;
+    driver -> port3:e;
+    driver -> port4;
+
+    payload1:s -> port1:e;
+    payload2:s -> port3:e;
+    edge [style=""];
+
+    subgraph cluster_topology {
+        label="Topology Manager";
+        labelloc=bottom;
+
+        /* Topology references */
+        mstb1 -> {port1, port2};
+        port1 -> mstb2;
+        port2 -> mstb3 -> {port3, port4};
+        port3 -> mstb4;
+
+        /* Malloc references */
+        edge [style=dashed;dir=back];
+        mstb1 -> {port1, port2};
+        port1 -> mstb2;
+        port2 -> mstb3 -> {port3, port4};
+        port3 -> mstb4;
+    }
+
+    driver [label="DRM driver";style=filled;shape=box;fillcolor=lightblue];
+
+    payload1 [label="Payload #1";style=filled;shape=box;fillcolor=lightblue];
+    payload2 [label="Payload #2";style=filled;shape=box;fillcolor=lightblue];
+
+    mstb1 [label="MSTB #1";style=filled;fillcolor=palegreen;shape=oval];
+    mstb2 [label="MSTB #2";style=filled;fillcolor=palegreen;shape=oval];
+    mstb3 [label="MSTB #3";style=filled;fillcolor=palegreen;shape=oval];
+    mstb4 [label="MSTB #4";style=filled;fillcolor=palegreen;shape=oval];
+
+    port1 [label="Port #1";shape=oval];
+    port2 [label="Port #2";shape=oval];
+    port3 [label="Port #3";shape=oval];
+    port4 [label="Port #4";shape=oval];
+}
diff --git a/Documentation/gpu/dp-mst/topology-figure-2.dot b/Documentation/gpu/dp-mst/topology-figure-2.dot
new file mode 100644
index 000000000..4243dd173
--- /dev/null
+++ b/Documentation/gpu/dp-mst/topology-figure-2.dot
@@ -0,0 +1,56 @@
+digraph T {
+    /* Make sure our payloads are always drawn below the driver node */
+    subgraph cluster_driver {
+        fillcolor = grey;
+        style = filled;
+        driver -> {payload1, payload2} [dir=none];
+    }
+
+    /* Driver malloc references */
+    edge [style=dashed];
+    driver -> port1;
+    driver -> port2;
+    driver -> port3:e;
+    driver -> port4 [color=red];
+
+    payload1:s -> port1:e;
+    payload2:s -> port3:e;
+    edge [style=""];
+
+    subgraph cluster_topology {
+        label="Topology Manager";
+        labelloc=bottom;
+
+        /* Topology references */
+        mstb1 -> {port1, port2};
+        port1 -> mstb2;
+        edge [color=red];
+        port2 -> mstb3 -> {port3, port4};
+        port3 -> mstb4;
+        edge [color=""];
+
+        /* Malloc references */
+        edge [style=dashed;dir=back];
+        mstb1 -> {port1, port2};
+        port1 -> mstb2;
+        port2 -> mstb3 -> port3;
+        edge [color=red];
+        mstb3 -> port4;
+        port3 -> mstb4;
+    }
+
+    mstb1 [label="MSTB #1";style=filled;fillcolor=palegreen];
+    mstb2 [label="MSTB #2";style=filled;fillcolor=palegreen];
+    mstb3 [label="MSTB #3";style=filled;fillcolor=palegreen];
+    mstb4 [label="MSTB #4";style=filled;fillcolor=grey];
+
+    port1 [label="Port #1"];
+    port2 [label="Port #2"];
+    port3 [label="Port #3"];
+    port4 [label="Port #4";style=filled;fillcolor=grey];
+
+    driver [label="DRM driver";style=filled;shape=box;fillcolor=lightblue];
+
+    payload1 [label="Payload #1";style=filled;shape=box;fillcolor=lightblue];
+    payload2 [label="Payload #2";style=filled;shape=box;fillcolor=lightblue];
+}
diff --git a/Documentation/gpu/dp-mst/topology-figure-3.dot b/Documentation/gpu/dp-mst/topology-figure-3.dot
new file mode 100644
index 000000000..6cd78d067
--- /dev/null
+++ b/Documentation/gpu/dp-mst/topology-figure-3.dot
@@ -0,0 +1,59 @@
+digraph T {
+    /* Make sure our payloads are always drawn below the driver node */
+    subgraph cluster_driver {
+        fillcolor = grey;
+        style = filled;
+        edge [dir=none];
+        driver -> payload1;
+        driver -> payload2 [penwidth=3];
+        edge [dir=""];
+    }
+
+    /* Driver malloc references */
+    edge [style=dashed];
+    driver -> port1;
+    driver -> port2;
+    driver -> port3:e;
+    driver -> port4 [color=grey];
+    payload1:s -> port1:e;
+    payload2:s -> port3:e [penwidth=3];
+    edge [style=""];
+
+    subgraph cluster_topology {
+        label="Topology Manager";
+        labelloc=bottom;
+
+        /* Topology references */
+        mstb1 -> {port1, port2};
+        port1 -> mstb2;
+        edge [color=grey];
+        port2 -> mstb3 -> {port3, port4};
+        port3 -> mstb4;
+        edge [color=""];
+
+        /* Malloc references */
+        edge [style=dashed;dir=back];
+        mstb1 -> {port1, port2};
+        port1 -> mstb2;
+        port2 -> mstb3 [penwidth=3];
+        mstb3 -> port3 [penwidth=3];
+        edge [color=grey];
+        mstb3 -> port4;
+        port3 -> mstb4;
+    }
+
+    mstb1 [label="MSTB #1";style=filled;fillcolor=palegreen];
+    mstb2 [label="MSTB #2";style=filled;fillcolor=palegreen];
+    mstb3 [label="MSTB #3";style=filled;fillcolor=palegreen;penwidth=3];
+    mstb4 [label="MSTB #4";style=filled;fillcolor=grey];
+
+    port1 [label="Port #1"];
+    port2 [label="Port #2";penwidth=5];
+    port3 [label="Port #3";penwidth=3];
+    port4 [label="Port #4";style=filled;fillcolor=grey];
+
+    driver [label="DRM driver";style=filled;shape=box;fillcolor=lightblue];
+
+    payload1 [label="Payload #1";style=filled;shape=box;fillcolor=lightblue];
+    payload2 [label="Payload #2";style=filled;shape=box;fillcolor=lightblue;penwidth=3];
+}