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, 54 insertions, 0 deletions

diff --git a/scripts/coccinelle/misc/doubleinit.cocci b/scripts/coccinelle/misc/doubleinit.cocci
new file mode 100644
index 000000000..7dbfde3f4
--- /dev/null
+++ b/scripts/coccinelle/misc/doubleinit.cocci
@@ -0,0 +1,54 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/// Find duplicate field initializations.  This has a high rate of false
+/// positives due to #ifdefs, which Coccinelle is not aware of in a structure
+/// initialization.
+///
+// Confidence: Low
+// Copyright: (C) 2010-2012 Nicolas Palix.
+// Copyright: (C) 2010-2012 Julia Lawall, INRIA/LIP6.
+// Copyright: (C) 2010-2012 Gilles Muller, INRIA/LiP6.
+// URL: https://coccinelle.gitlabpages.inria.fr/website
+// Comments: requires at least Coccinelle 0.2.4, lex or parse error otherwise
+// Options: --no-includes --include-headers
+
+virtual org
+virtual report
+
+@r@
+identifier I, s, fld;
+position p0,p;
+expression E;
+@@
+
+struct I s =@p0 { ..., .fld@p = E, ...};
+
+@s@
+identifier I, s, r.fld;
+position r.p0,p;
+expression E;
+@@
+
+struct I s =@p0 { ..., .fld@p = E, ...};
+
+@script:python depends on org@
+p0 << r.p0;
+fld << r.fld;
+ps << s.p;
+pr << r.p;
+@@
+
+if int(ps[0].line) < int(pr[0].line) or (int(ps[0].line) == int(pr[0].line) and int(ps[0].column) < int(pr[0].column)):
+  cocci.print_main(fld,p0)
+  cocci.print_secs("s",ps)
+  cocci.print_secs("r",pr)
+
+@script:python depends on report@
+p0 << r.p0;
+fld << r.fld;
+ps << s.p;
+pr << r.p;
+@@
+
+if int(ps[0].line) < int(pr[0].line) or (int(ps[0].line) == int(pr[0].line) and int(ps[0].column) < int(pr[0].column)):
+  msg = "%s: first occurrence line %s, second occurrence line %s" % (fld,ps[0].line,pr[0].line)
+  coccilib.report.print_report(p0[0],msg)