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.

6 files changed, 312 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/hwlock/allwinner,sun6i-a31-hwspinlock.yaml b/Documentation/devicetree/bindings/hwlock/allwinner,sun6i-a31-hwspinlock.yaml
new file mode 100644
index 000000000..584cce321
--- /dev/null
+++ b/Documentation/devicetree/bindings/hwlock/allwinner,sun6i-a31-hwspinlock.yaml
@@ -0,0 +1,53 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/hwlock/allwinner,sun6i-a31-hwspinlock.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: SUN6I hardware spinlock driver for Allwinner sun6i compatible SoCs
+
+maintainers:
+  - Wilken Gottwalt <wilken.gottwalt@posteo.net>
+
+description:
+  The hardware unit provides semaphores between the ARM cores and the embedded
+  companion core on the SoC.
+
+properties:
+  compatible:
+    const: allwinner,sun6i-a31-hwspinlock
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  resets:
+    maxItems: 1
+
+  '#hwlock-cells':
+    const: 1
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - resets
+  - "#hwlock-cells"
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/sun8i-a23-a33-ccu.h>
+    #include <dt-bindings/reset/sun8i-a23-a33-ccu.h>
+
+    hwlock@1c18000 {
+        compatible = "allwinner,sun6i-a31-hwspinlock";
+        reg = <0x01c18000 0x1000>;
+        clocks = <&ccu CLK_BUS_SPINLOCK>;
+        resets = <&ccu RST_BUS_SPINLOCK>;
+        #hwlock-cells = <1>;
+    };
+...
diff --git a/Documentation/devicetree/bindings/hwlock/hwlock.txt b/Documentation/devicetree/bindings/hwlock/hwlock.txt
new file mode 100644
index 000000000..085d1f5c9
--- /dev/null
+++ b/Documentation/devicetree/bindings/hwlock/hwlock.txt
@@ -0,0 +1,59 @@
+Generic hwlock bindings
+=======================
+
+Generic bindings that are common to all the hwlock platform specific driver
+implementations.
+
+Please also look through the individual platform specific hwlock binding
+documentations for identifying any additional properties specific to that
+platform.
+
+hwlock providers:
+=================
+
+Required properties:
+- #hwlock-cells:        Specifies the number of cells needed to represent a
+                        specific lock.
+
+hwlock users:
+=============
+
+Consumers that require specific hwlock(s) should specify them using the
+property "hwlocks", and an optional "hwlock-names" property.
+
+Required properties:
+- hwlocks:              List of phandle to a hwlock provider node and an
+                        associated hwlock args specifier as indicated by
+                        #hwlock-cells. The list can have just a single hwlock
+                        or multiple hwlocks, with each hwlock represented by
+                        a phandle and a corresponding args specifier.
+
+Optional properties:
+- hwlock-names:         List of hwlock name strings defined in the same order
+                        as the hwlocks, with one name per hwlock. Consumers can
+                        use the hwlock-names to match and get a specific hwlock.
+
+
+1. Example of a node using a single specific hwlock:
+
+The following example has a node requesting a hwlock in the bank defined by
+the node hwlock1. hwlock1 is a hwlock provider with an argument specifier
+of length 1.
+
+	node {
+		...
+		hwlocks = <&hwlock1 2>;
+		...
+	};
+
+2. Example of a node using multiple specific hwlocks:
+
+The following example has a node requesting two hwlocks, a hwlock within
+the hwlock device node 'hwlock1' with #hwlock-cells value of 1, and another
+hwlock within the hwlock device node 'hwlock2' with #hwlock-cells value of 2.
+
+	node {
+		...
+		hwlocks = <&hwlock1 2>, <&hwlock2 0 3>;
+		...
+	};
diff --git a/Documentation/devicetree/bindings/hwlock/qcom-hwspinlock.yaml b/Documentation/devicetree/bindings/hwlock/qcom-hwspinlock.yaml
new file mode 100644
index 000000000..ee2726149
--- /dev/null
+++ b/Documentation/devicetree/bindings/hwlock/qcom-hwspinlock.yaml
@@ -0,0 +1,55 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/hwlock/qcom-hwspinlock.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Qualcomm Hardware Mutex Block
+
+maintainers:
+  - Bjorn Andersson <bjorn.andersson@linaro.org>
+
+description:
+  The hardware block provides mutexes utilized between different processors on
+  the SoC as part of the communication protocol used by these processors.
+
+properties:
+  compatible:
+    oneOf:
+      - enum:
+          - qcom,sfpb-mutex
+          - qcom,tcsr-mutex
+      - items:
+          - enum:
+              - qcom,apq8084-tcsr-mutex
+              - qcom,ipq6018-tcsr-mutex
+              - qcom,msm8226-tcsr-mutex
+              - qcom,msm8994-tcsr-mutex
+          - const: qcom,tcsr-mutex
+      - items:
+          - enum:
+              - qcom,msm8974-tcsr-mutex
+          - const: qcom,tcsr-mutex
+          - const: syscon
+
+  reg:
+    maxItems: 1
+
+  '#hwlock-cells':
+    const: 1
+
+required:
+  - compatible
+  - reg
+  - '#hwlock-cells'
+
+additionalProperties: false
+
+examples:
+  - |
+    hwlock@1f40000 {
+        compatible = "qcom,tcsr-mutex";
+        reg = <0x01f40000 0x40000>;
+        #hwlock-cells = <1>;
+    };
+...
diff --git a/Documentation/devicetree/bindings/hwlock/sprd,hwspinlock-r3p0.yaml b/Documentation/devicetree/bindings/hwlock/sprd,hwspinlock-r3p0.yaml
new file mode 100644
index 000000000..abe11df25
--- /dev/null
+++ b/Documentation/devicetree/bindings/hwlock/sprd,hwspinlock-r3p0.yaml
@@ -0,0 +1,50 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/hwlock/sprd,hwspinlock-r3p0.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Spreadtrum hardware spinlock
+
+maintainers:
+  - Orson Zhai <orsonzhai@gmail.com>
+  - Baolin Wang <baolin.wang7@gmail.com>
+  - Chunyan Zhang <zhang.lyra@gmail.com>
+
+properties:
+  compatible:
+    const: sprd,hwspinlock-r3p0
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  clock-names:
+    const: enable
+
+  '#hwlock-cells':
+    const: 1
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - clock-names
+  - '#hwlock-cells'
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/sprd,sc9860-clk.h>
+
+    hwlock@40500000 {
+      compatible = "sprd,hwspinlock-r3p0";
+      reg = <0x40500000 0x1000>;
+      clocks = <&aon_gate CLK_SPLK_EB>;
+      clock-names = "enable";
+      #hwlock-cells = <1>;
+    };
+...
diff --git a/Documentation/devicetree/bindings/hwlock/st,stm32-hwspinlock.yaml b/Documentation/devicetree/bindings/hwlock/st,stm32-hwspinlock.yaml
new file mode 100644
index 000000000..829d1fdf4
--- /dev/null
+++ b/Documentation/devicetree/bindings/hwlock/st,stm32-hwspinlock.yaml
@@ -0,0 +1,49 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/hwlock/st,stm32-hwspinlock.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: STMicroelectronics STM32 Hardware Spinlock
+
+maintainers:
+  - Fabien Dessenne <fabien.dessenne@foss.st.com>
+
+properties:
+  "#hwlock-cells":
+    const: 1
+
+  compatible:
+    const: st,stm32-hwspinlock
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  clock-names:
+    items:
+      - const: hsem
+
+required:
+  - "#hwlock-cells"
+  - compatible
+  - reg
+  - clocks
+  - clock-names
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/stm32mp1-clks.h>
+    hwspinlock@4c000000 {
+        compatible = "st,stm32-hwspinlock";
+        #hwlock-cells = <1>;
+        reg = <0x4c000000 0x400>;
+        clocks = <&rcc HSEM>;
+        clock-names = "hsem";
+    };
+
+...
diff --git a/Documentation/devicetree/bindings/hwlock/ti,omap-hwspinlock.yaml b/Documentation/devicetree/bindings/hwlock/ti,omap-hwspinlock.yaml
new file mode 100644
index 000000000..5ba60d532
--- /dev/null
+++ b/Documentation/devicetree/bindings/hwlock/ti,omap-hwspinlock.yaml
@@ -0,0 +1,46 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/hwlock/ti,omap-hwspinlock.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: TI HwSpinlock for OMAP and K3 based SoCs
+
+maintainers:
+  - Suman Anna <s-anna@ti.com>
+
+properties:
+  compatible:
+    enum:
+      - ti,omap4-hwspinlock  # for OMAP44xx, OMAP54xx, AM33xx, AM43xx, DRA7xx SoCs
+      - ti,am64-hwspinlock   # for K3 AM64x SoCs
+      - ti,am654-hwspinlock  # for K3 AM65x, J721E and J7200 SoCs
+
+  reg:
+    maxItems: 1
+
+  "#hwlock-cells":
+    const: 1
+    description: |
+      The OMAP hwspinlock users will use a 0-indexed relative hwlock number as
+      the argument specifier value for requesting a specific hwspinlock within
+      a hwspinlock bank.
+
+      Please look at the generic hwlock binding for usage information for
+      consumers, "Documentation/devicetree/bindings/hwlock/hwlock.txt"
+
+required:
+  - compatible
+  - reg
+  - "#hwlock-cells"
+
+additionalProperties: false
+
+examples:
+
+  - |
+    spinlock@4a0f6000 {
+        compatible = "ti,omap4-hwspinlock";
+        reg = <0x4a0f6000 0x1000>;
+        #hwlock-cells = <1>;
+    };