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, 220 insertions, 0 deletions

diff --git a/include/trace/events/target.h b/include/trace/events/target.h
new file mode 100644
index 000000000..7e2e20ba2
--- /dev/null
+++ b/include/trace/events/target.h
@@ -0,0 +1,220 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM target
+
+#if !defined(_TRACE_TARGET_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_TARGET_H
+
+#include <linux/tracepoint.h>
+#include <linux/trace_seq.h>
+#include <scsi/scsi_proto.h>
+#include <scsi/scsi_tcq.h>
+#include <target/target_core_base.h>
+
+/* cribbed verbatim from <trace/event/scsi.h> */
+#define scsi_opcode_name(opcode)	{ opcode, #opcode }
+#define show_opcode_name(val)					\
+	__print_symbolic(val,					\
+		scsi_opcode_name(TEST_UNIT_READY),		\
+		scsi_opcode_name(REZERO_UNIT),			\
+		scsi_opcode_name(REQUEST_SENSE),		\
+		scsi_opcode_name(FORMAT_UNIT),			\
+		scsi_opcode_name(READ_BLOCK_LIMITS),		\
+		scsi_opcode_name(REASSIGN_BLOCKS),		\
+		scsi_opcode_name(INITIALIZE_ELEMENT_STATUS),	\
+		scsi_opcode_name(READ_6),			\
+		scsi_opcode_name(WRITE_6),			\
+		scsi_opcode_name(SEEK_6),			\
+		scsi_opcode_name(READ_REVERSE),			\
+		scsi_opcode_name(WRITE_FILEMARKS),		\
+		scsi_opcode_name(SPACE),			\
+		scsi_opcode_name(INQUIRY),			\
+		scsi_opcode_name(RECOVER_BUFFERED_DATA),	\
+		scsi_opcode_name(MODE_SELECT),			\
+		scsi_opcode_name(RESERVE_6),			\
+		scsi_opcode_name(RELEASE_6),			\
+		scsi_opcode_name(COPY),				\
+		scsi_opcode_name(ERASE),			\
+		scsi_opcode_name(MODE_SENSE),			\
+		scsi_opcode_name(START_STOP),			\
+		scsi_opcode_name(RECEIVE_DIAGNOSTIC),		\
+		scsi_opcode_name(SEND_DIAGNOSTIC),		\
+		scsi_opcode_name(ALLOW_MEDIUM_REMOVAL),		\
+		scsi_opcode_name(SET_WINDOW),			\
+		scsi_opcode_name(READ_CAPACITY),		\
+		scsi_opcode_name(READ_10),			\
+		scsi_opcode_name(WRITE_10),			\
+		scsi_opcode_name(SEEK_10),			\
+		scsi_opcode_name(POSITION_TO_ELEMENT),		\
+		scsi_opcode_name(WRITE_VERIFY),			\
+		scsi_opcode_name(VERIFY),			\
+		scsi_opcode_name(SEARCH_HIGH),			\
+		scsi_opcode_name(SEARCH_EQUAL),			\
+		scsi_opcode_name(SEARCH_LOW),			\
+		scsi_opcode_name(SET_LIMITS),			\
+		scsi_opcode_name(PRE_FETCH),			\
+		scsi_opcode_name(READ_POSITION),		\
+		scsi_opcode_name(SYNCHRONIZE_CACHE),		\
+		scsi_opcode_name(LOCK_UNLOCK_CACHE),		\
+		scsi_opcode_name(READ_DEFECT_DATA),		\
+		scsi_opcode_name(MEDIUM_SCAN),			\
+		scsi_opcode_name(COMPARE),			\
+		scsi_opcode_name(COPY_VERIFY),			\
+		scsi_opcode_name(WRITE_BUFFER),			\
+		scsi_opcode_name(READ_BUFFER),			\
+		scsi_opcode_name(UPDATE_BLOCK),			\
+		scsi_opcode_name(READ_LONG),			\
+		scsi_opcode_name(WRITE_LONG),			\
+		scsi_opcode_name(CHANGE_DEFINITION),		\
+		scsi_opcode_name(WRITE_SAME),			\
+		scsi_opcode_name(UNMAP),			\
+		scsi_opcode_name(READ_TOC),			\
+		scsi_opcode_name(LOG_SELECT),			\
+		scsi_opcode_name(LOG_SENSE),			\
+		scsi_opcode_name(XDWRITEREAD_10),		\
+		scsi_opcode_name(MODE_SELECT_10),		\
+		scsi_opcode_name(RESERVE_10),			\
+		scsi_opcode_name(RELEASE_10),			\
+		scsi_opcode_name(MODE_SENSE_10),		\
+		scsi_opcode_name(PERSISTENT_RESERVE_IN),	\
+		scsi_opcode_name(PERSISTENT_RESERVE_OUT),	\
+		scsi_opcode_name(VARIABLE_LENGTH_CMD),		\
+		scsi_opcode_name(REPORT_LUNS),			\
+		scsi_opcode_name(MAINTENANCE_IN),		\
+		scsi_opcode_name(MAINTENANCE_OUT),		\
+		scsi_opcode_name(MOVE_MEDIUM),			\
+		scsi_opcode_name(EXCHANGE_MEDIUM),		\
+		scsi_opcode_name(READ_12),			\
+		scsi_opcode_name(WRITE_12),			\
+		scsi_opcode_name(WRITE_VERIFY_12),		\
+		scsi_opcode_name(SEARCH_HIGH_12),		\
+		scsi_opcode_name(SEARCH_EQUAL_12),		\
+		scsi_opcode_name(SEARCH_LOW_12),		\
+		scsi_opcode_name(READ_ELEMENT_STATUS),		\
+		scsi_opcode_name(SEND_VOLUME_TAG),		\
+		scsi_opcode_name(WRITE_LONG_2),			\
+		scsi_opcode_name(READ_16),			\
+		scsi_opcode_name(WRITE_16),			\
+		scsi_opcode_name(VERIFY_16),			\
+		scsi_opcode_name(WRITE_SAME_16),		\
+		scsi_opcode_name(SERVICE_ACTION_IN_16),		\
+		scsi_opcode_name(SAI_READ_CAPACITY_16),		\
+		scsi_opcode_name(SAI_GET_LBA_STATUS),		\
+		scsi_opcode_name(MI_REPORT_TARGET_PGS),		\
+		scsi_opcode_name(MO_SET_TARGET_PGS),		\
+		scsi_opcode_name(READ_32),			\
+		scsi_opcode_name(WRITE_32),			\
+		scsi_opcode_name(WRITE_SAME_32),		\
+		scsi_opcode_name(ATA_16),			\
+		scsi_opcode_name(ATA_12))
+
+#define show_task_attribute_name(val)				\
+	__print_symbolic(val,					\
+		{ TCM_SIMPLE_TAG,	"SIMPLE"	},	\
+		{ TCM_HEAD_TAG,		"HEAD"		},	\
+		{ TCM_ORDERED_TAG,	"ORDERED"	},	\
+		{ TCM_ACA_TAG,		"ACA"		} )
+
+#define show_scsi_status_name(val)				\
+	__print_symbolic(val,					\
+		{ SAM_STAT_GOOD,	"GOOD" },		\
+		{ SAM_STAT_CHECK_CONDITION, "CHECK CONDITION" }, \
+		{ SAM_STAT_CONDITION_MET, "CONDITION MET" },	\
+		{ SAM_STAT_BUSY,	"BUSY" },		\
+		{ SAM_STAT_INTERMEDIATE, "INTERMEDIATE" },	\
+		{ SAM_STAT_INTERMEDIATE_CONDITION_MET, "INTERMEDIATE CONDITION MET" }, \
+		{ SAM_STAT_RESERVATION_CONFLICT, "RESERVATION CONFLICT" }, \
+		{ SAM_STAT_COMMAND_TERMINATED, "COMMAND TERMINATED" }, \
+		{ SAM_STAT_TASK_SET_FULL, "TASK SET FULL" },	\
+		{ SAM_STAT_ACA_ACTIVE, "ACA ACTIVE" },		\
+		{ SAM_STAT_TASK_ABORTED, "TASK ABORTED" } )
+
+TRACE_EVENT(target_sequencer_start,
+
+	TP_PROTO(struct se_cmd *cmd),
+
+	TP_ARGS(cmd),
+
+	TP_STRUCT__entry(
+		__field( unsigned int,	unpacked_lun	)
+		__field( unsigned long long,	tag	)
+		__field( unsigned int,	opcode		)
+		__field( unsigned int,	data_length	)
+		__field( unsigned int,	task_attribute  )
+		__field( unsigned char,	control		)
+		__array( unsigned char,	cdb, TCM_MAX_COMMAND_SIZE	)
+		__string( initiator,	cmd->se_sess->se_node_acl->initiatorname	)
+	),
+
+	TP_fast_assign(
+		__entry->unpacked_lun	= cmd->orig_fe_lun;
+		__entry->tag		= cmd->tag;
+		__entry->opcode		= cmd->t_task_cdb[0];
+		__entry->data_length	= cmd->data_length;
+		__entry->task_attribute	= cmd->sam_task_attr;
+		__entry->control	= scsi_command_control(cmd->t_task_cdb);
+		memcpy(__entry->cdb, cmd->t_task_cdb, TCM_MAX_COMMAND_SIZE);
+		__assign_str(initiator);
+	),
+
+	TP_printk("%s -> LUN %03u tag %#llx %s data_length %6u  CDB %s  (TA:%s C:%02x)",
+		  __get_str(initiator), __entry->unpacked_lun,
+		  __entry->tag, show_opcode_name(__entry->opcode),
+		  __entry->data_length, __print_hex(__entry->cdb, 16),
+		  show_task_attribute_name(__entry->task_attribute),
+		  __entry->control
+	)
+);
+
+TRACE_EVENT(target_cmd_complete,
+
+	TP_PROTO(struct se_cmd *cmd),
+
+	TP_ARGS(cmd),
+
+	TP_STRUCT__entry(
+		__field( unsigned int,	unpacked_lun	)
+		__field( unsigned long long,	tag	)
+		__field( unsigned int,	opcode		)
+		__field( unsigned int,	data_length	)
+		__field( unsigned int,	task_attribute  )
+		__field( unsigned char,	control		)
+		__field( unsigned char,	scsi_status	)
+		__field( unsigned char,	sense_length	)
+		__array( unsigned char,	cdb, TCM_MAX_COMMAND_SIZE	)
+		__array( unsigned char,	sense_data, 18	)
+		__string(initiator,	cmd->se_sess->se_node_acl->initiatorname)
+	),
+
+	TP_fast_assign(
+		__entry->unpacked_lun	= cmd->orig_fe_lun;
+		__entry->tag		= cmd->tag;
+		__entry->opcode		= cmd->t_task_cdb[0];
+		__entry->data_length	= cmd->data_length;
+		__entry->task_attribute	= cmd->sam_task_attr;
+		__entry->control	= scsi_command_control(cmd->t_task_cdb);
+		__entry->scsi_status	= cmd->scsi_status;
+		__entry->sense_length	= cmd->scsi_status == SAM_STAT_CHECK_CONDITION ?
+			min(18, ((u8 *) cmd->sense_buffer)[SPC_ADD_SENSE_LEN_OFFSET] + 8) : 0;
+		memcpy(__entry->cdb, cmd->t_task_cdb, TCM_MAX_COMMAND_SIZE);
+		memcpy(__entry->sense_data, cmd->sense_buffer, __entry->sense_length);
+		__assign_str(initiator);
+	),
+
+	TP_printk("%s <- LUN %03u tag %#llx status %s (sense len %d%s%s)  %s data_length %6u  CDB %s  (TA:%s C:%02x)",
+		  __get_str(initiator), __entry->unpacked_lun,
+		  __entry->tag,
+		  show_scsi_status_name(__entry->scsi_status),
+		  __entry->sense_length, __entry->sense_length ? " / " : "",
+		  __print_hex(__entry->sense_data, __entry->sense_length),
+		  show_opcode_name(__entry->opcode),
+		  __entry->data_length, __print_hex(__entry->cdb, 16),
+		  show_task_attribute_name(__entry->task_attribute),
+		  __entry->control
+	)
+);
+
+#endif /*  _TRACE_TARGET_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>