linux/kernel/rcu
Paul E. McKenney 61bbcfb505 srcu: Push srcu_node allocation to GP when non-preemptible
When the srcutree.convert_to_big and srcutree.big_cpu_lim kernel boot
parameters specify initialization-time allocation of the srcu_node
tree for statically allocated srcu_struct structures (for example, in
DEFINE_SRCU() at build time instead of init_srcu_struct() at runtime),
init_srcu_struct_nodes() will attempt to dynamically allocate this tree
at the first run-time update-side use of this srcu_struct structure,
but while holding a raw spinlock.  Because the memory allocator can
acquire non-raw spinlocks, this can result in lockdep splats.

This commit therefore uses the same SRCU_SIZE_ALLOC trick that is used
when the first run-time update-side use of this srcu_struct structure
happens before srcu_init() is called.  The actual allocation then takes
place from workqueue context at the ends of upcoming SRCU grace periods.

[boqun: Adjust the sha1 of the Fixes tag]

Fixes: 175b45ed34 ("srcu: Use raw spinlocks so call_srcu() can be used under preempt_disable()")
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Boqun Feng <boqun@kernel.org>
2026-03-25 08:59:02 -07:00
..
Kconfig rcu: Add noinstr-fast rcu_read_{,un}lock_tasks_trace() APIs 2026-01-01 16:39:46 +08:00
Kconfig.debug rcu: Add a small-width RCU watching counter debug option 2025-10-28 17:32:56 +01:00
Makefile rcuperf: Change rcuperf to rcuscale 2020-08-24 18:39:24 -07:00
rcu_segcblist.c rcu/nocb: Simplify (de-)offloading state machine 2024-09-09 00:03:55 +05:30
rcu_segcblist.h rcu: Remove unused declaration rcu_segcblist_offload() 2024-10-22 15:36:56 +02:00
rcu.h srcu: Use raw spinlocks so call_srcu() can be used under preempt_disable() 2026-03-25 08:55:50 -07:00
rcuscale.c Convert remaining multi-line kmalloc_obj/flex GFP_KERNEL uses 2026-02-22 08:26:33 -08:00
rcutorture.c Convert remaining multi-line kmalloc_obj/flex GFP_KERNEL uses 2026-02-22 08:26:33 -08:00
refscale.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
srcutiny.c srcu: Permit Tiny SRCU srcu_read_unlock() with interrupts disabled 2025-11-05 23:58:11 +01:00
srcutree.c srcu: Push srcu_node allocation to GP when non-preemptible 2026-03-25 08:59:02 -07:00
sync.c rcu: Eliminate lockless accesses to rcu_sync->gp_count 2024-07-04 13:48:57 -07:00
tasks.h Convert remaining multi-line kmalloc_obj/flex GFP_KERNEL uses 2026-02-22 08:26:33 -08:00
tiny.c sched: Provide and use set_need_resched_current() 2025-11-20 22:26:09 +01:00
tree_exp.h rcu: Make expedited RCU CPU stall warnings detect stall-end races 2026-01-07 21:58:26 +08:00
tree_nocb.h rcu/nocb: Extract nocb_defer_wakeup_cancel() helper 2026-01-23 11:12:25 -08:00
tree_plugin.h rcu: Fix rcu_read_unlock() deadloop due to softirq 2026-01-07 21:58:37 +08:00
tree_stall.h sched: Provide and use set_need_resched_current() 2025-11-20 22:26:09 +01:00
tree.c Merge branch 'rcu-nocb.20260123a' 2026-01-23 11:15:36 -08:00
tree.h Merge branch 'rcu-nocb.20260123a' 2026-01-23 11:15:36 -08:00
update.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00