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.

1 files changed, 274 insertions, 0 deletions

diff --git a/tools/usb/hcd-tests.sh b/tools/usb/hcd-tests.sh
new file mode 100644
index 000000000..73f914d13
--- /dev/null
+++ b/tools/usb/hcd-tests.sh
@@ -0,0 +1,274 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+#
+# test types can be passed on the command line:
+#
+# - control: any device can do this
+# - out, in:  out needs 'bulk sink' firmware, in needs 'bulk src'
+# - iso-out, iso-in:  out needs 'iso sink' firmware, in needs 'iso src'
+# - halt: needs bulk sink+src, tests halt set/clear from host
+# - unlink: needs bulk sink and/or src, test HCD unlink processing
+# - loop: needs firmware that will buffer N transfers
+#
+# run it for hours, days, weeks.
+#
+
+#
+# this default provides a steady test load for a bulk device
+#
+TYPES='control out in'
+#TYPES='control out in halt'
+
+#
+# to test HCD code
+#
+#  - include unlink tests
+#  - add some ${RANDOM}ness
+#  - connect several devices concurrently (same HC)
+#  - keep HC's IRQ lines busy with unrelated traffic (IDE, net, ...)
+#  - add other concurrent system loads
+#
+
+declare -i COUNT BUFLEN
+
+COUNT=50000
+BUFLEN=2048
+
+# NOTE:  the 'in' and 'out' cases are usually bulk, but can be
+# set up to use interrupt transfers by 'usbtest' module options
+
+
+if [ "$DEVICE" = "" ]; then
+	echo "testing ALL recognized usbtest devices"
+	echo ""
+	TEST_ARGS="-a"
+else
+	TEST_ARGS=""
+fi
+
+do_test ()
+{
+    if ! ./testusb $TEST_ARGS -s $BUFLEN -c $COUNT $* 2>/dev/null
+    then
+	echo "FAIL"
+	exit 1
+    fi
+}
+
+ARGS="$*"
+
+if [ "$ARGS" = "" ];
+then
+    ARGS="$TYPES"
+fi
+
+# FIXME use /sys/bus/usb/device/$THIS/bConfigurationValue to
+# check and change configs
+
+CONFIG=''
+
+check_config ()
+{
+    if [ "$CONFIG" = "" ]; then
+	CONFIG=$1
+	echo "assuming $CONFIG configuration"
+	return
+    fi
+    if [ "$CONFIG" = $1 ]; then
+	return
+    fi
+
+    echo "** device must be in $1 config, but it's $CONFIG instead"
+    exit 1
+}
+
+
+echo "TESTING:  $ARGS"
+
+while : true
+do
+    echo $(date)
+
+    for TYPE in $ARGS
+    do
+	# restore defaults
+	COUNT=5000
+	BUFLEN=2048
+
+	# FIXME automatically multiply COUNT by 10 when
+	# /sys/bus/usb/device/$THIS/speed == "480"
+
+#	COUNT=50000
+
+	case $TYPE in
+	control)
+	    # any device, in any configuration, can use this.
+	    echo '** Control test cases:'
+
+	    echo "test 9: ch9 postconfig"
+	    do_test -t 9 -c 5000
+	    echo "test 10: control queueing"
+	    do_test -t 10 -c 5000
+
+	    # this relies on some vendor-specific commands
+	    echo "test 14: control writes"
+	    do_test -t 14 -c 15000 -s 256 -v 1
+
+	    echo "test 21: control writes, unaligned"
+	    do_test -t 21 -c 100 -s 256 -v 1
+
+	    ;;
+
+	out)
+	    check_config sink-src
+	    echo '** Host Write (OUT) test cases:'
+
+	    echo "test 1: $COUNT transfers, same size"
+	    do_test -t 1
+	    echo "test 3: $COUNT transfers, variable/short size"
+	    do_test -t 3 -v 421
+
+	    COUNT=100
+	    echo "test 17: $COUNT transfers, unaligned DMA map by core"
+	    do_test -t 17
+
+	    echo "test 19: $COUNT transfers, unaligned DMA map by usb_alloc_coherent"
+	    do_test -t 19
+
+	    COUNT=2000
+	    echo "test 5: $COUNT scatterlists, same size entries"
+	    do_test -t 5
+
+	    # try to trigger short OUT processing bugs
+	    echo "test 7a: $COUNT scatterlists, variable size/short entries"
+	    do_test -t 7 -v 579
+	    BUFLEN=4096
+	    echo "test 7b: $COUNT scatterlists, variable size/bigger entries"
+	    do_test -t 7 -v 41
+	    BUFLEN=64
+	    echo "test 7c: $COUNT scatterlists, variable size/micro entries"
+	    do_test -t 7 -v 63
+	    ;;
+
+	iso-out)
+	    check_config sink-src
+	    echo '** Host ISOCHRONOUS Write (OUT) test cases:'
+
+	    # at peak iso transfer rates:
+	    # - usb 2.0 high bandwidth, this is one frame.
+	    # - usb 1.1, it's twenty-four frames.
+	    BUFLEN=24500
+
+	    COUNT=1000
+
+# COUNT=10000
+
+	    echo "test 15: $COUNT transfers, same size"
+	    # do_test -t 15 -g 3 -v 0
+	    BUFLEN=32768
+	    do_test -t 15 -g 8 -v 0
+
+	    # FIXME it'd make sense to have an iso OUT test issuing
+	    # short writes on more packets than the last one
+
+	    COUNT=100
+	    echo "test 22: $COUNT transfers, non aligned"
+	    do_test -t 22 -g 8 -v 0
+
+	    ;;
+
+	in)
+	    check_config sink-src
+	    echo '** Host Read (IN) test cases:'
+
+	    # NOTE:  these "variable size" reads are just multiples
+	    # of 512 bytes, no EOVERFLOW testing is done yet
+
+	    echo "test 2: $COUNT transfers, same size"
+	    do_test -t 2
+	    echo "test 4: $COUNT transfers, variable size"
+	    do_test -t 4
+
+	    COUNT=100
+	    echo "test 18: $COUNT transfers, unaligned DMA map by core"
+	    do_test -t 18
+
+	    echo "test 20: $COUNT transfers, unaligned DMA map by usb_alloc_coherent"
+	    do_test -t 20
+
+	    COUNT=2000
+	    echo "test 6: $COUNT scatterlists, same size entries"
+	    do_test -t 6
+	    echo "test 8: $COUNT scatterlists, variable size entries"
+	    do_test -t 8
+	    ;;
+
+	iso-in)
+	    check_config sink-src
+	    echo '** Host ISOCHRONOUS Read (IN) test cases:'
+
+	    # at peak iso transfer rates:
+	    # - usb 2.0 high bandwidth, this is one frame.
+	    # - usb 1.1, it's twenty-four frames.
+	    BUFLEN=24500
+
+	    COUNT=1000
+
+# COUNT=10000
+
+	    echo "test 16: $COUNT transfers, same size"
+	    # do_test -t 16 -g 3 -v 0
+	    BUFLEN=32768
+	    do_test -t 16 -g 8 -v 0
+
+	    # FIXME since iso expects faults, it'd make sense
+	    # to have an iso IN test issuing short reads ...
+
+	    COUNT=100
+	    echo "test 23: $COUNT transfers, unaligned"
+	    do_test -t 23 -g 8 -v 0
+
+	    ;;
+
+	halt)
+	    # NOTE:  sometimes hardware doesn't cooperate well with halting
+	    # endpoints from the host side.  so long as mass-storage class
+	    # firmware can halt them from the device, don't worry much if
+	    # you can't make this test work on your device.
+	    COUNT=2000
+	    echo "test 13: $COUNT halt set/clear"
+	    do_test -t 13
+	    ;;
+
+	unlink)
+	    COUNT=2000
+	    echo "test 11: $COUNT read unlinks"
+	    do_test -t 11
+
+	    echo "test 12: $COUNT write unlinks"
+	    do_test -t 12
+	    ;;
+
+	loop)
+	    # defaults need too much buffering for ez-usb devices
+	    BUFLEN=2048
+	    COUNT=32
+
+	    # modprobe g_zero qlen=$COUNT buflen=$BUFLEN loopdefault
+	    check_config loopback
+
+	    # FIXME someone needs to write and merge a version of this
+
+	    echo "write $COUNT buffers of $BUFLEN bytes, read them back"
+
+	    echo "write $COUNT variable size buffers, read them back"
+
+	    ;;
+
+	*)
+	    echo "Don't understand test type $TYPE"
+	    exit 1;
+	esac
+	echo ''
+    done
+done