Zqiang 927d1f4f77 rcu/nocb: Fix WARN_ON_ONCE() in the rcu_nocb_bypass_lock() ... [ Upstream commit dda98810b5 ] For the kernels built with CONFIG_RCU_NOCB_CPU_DEFAULT_ALL=y and CONFIG_RCU_LAZY=y, the following scenarios will trigger WARN_ON_ONCE() in the rcu_nocb_bypass_lock() and rcu_nocb_wait_contended() functions: CPU2 CPU11 kthread rcu_nocb_cb_kthread ksys_write rcu_do_batch vfs_write rcu_torture_timer_cb proc_sys_write __kmem_cache_free proc_sys_call_handler kmemleak_free drop_caches_sysctl_handler delete_object_full drop_slab __delete_object shrink_slab put_object lazy_rcu_shrink_scan call_rcu rcu_nocb_flush_bypass __call_rcu_commn rcu_nocb_bypass_lock raw_spin_trylock(&rdp->nocb_bypass_lock) fail atomic_inc(&rdp->nocb_lock_contended); rcu_nocb_wait_contended WARN_ON_ONCE(smp_processor_id() != rdp->cpu); WARN_ON_ONCE(atomic_read(&rdp->nocb_lock_contended)) | |_ _ _ _ _ _ _ _ _ _same rdp and rdp->cpu != 11_ _ _ _ _ _ _ _ _ __| Reproduce this bug with "echo 3 > /proc/sys/vm/drop_caches". This commit therefore uses rcu_nocb_try_flush_bypass() instead of rcu_nocb_flush_bypass() in lazy_rcu_shrink_scan(). If the nocb_bypass queue is being flushed, then rcu_nocb_try_flush_bypass will return directly. Signed-off-by: Zqiang <qiang.zhang1211@gmail.com> Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org> Reviewed-by: Frederic Weisbecker <frederic@kernel.org> Reviewed-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Sasha Levin <sashal@kernel.org>		2024-04-13 13:10:04 +02:00
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Kconfig	rcu: Employ jiffies-based backstop to callback time limit	2023-05-11 13:42:39 -07:00
Kconfig.debug	rcu: Restrict access to RCU CPU stall notifiers	2023-12-12 02:31:22 +05:30
Makefile	rcuperf: Change rcuperf to rcuscale	2020-08-24 18:39:24 -07:00
rcu.h	rcu: Restrict access to RCU CPU stall notifiers	2023-12-12 02:31:22 +05:30
rcu_segcblist.c	rcu: Use rcu_segcblist_segempty() instead of open coding it	2023-10-04 17:33:18 +02:00
rcu_segcblist.h	rcu: Throttle callback invocation based on number of ready callbacks	2023-01-03 17:28:34 -08:00
rcuscale.c	rcuscale: Move rcu_scale_writer() schedule_timeout_uninterruptible() to _idle()	2023-07-14 15:01:49 -07:00
rcutorture.c	Merge branches 'doc.2023.12.13a', 'torture.2023.11.23a', 'fixes.2023.12.13a', 'rcu-tasks.2023.12.12b' and 'srcu.2023.12.13a' into rcu-merge.2023.12.13a	2023-12-14 01:21:31 +05:30
refscale.c	refscale: Print out additional module parameters	2023-09-11 23:02:18 +02:00
srcutiny.c	rcu: Dump memory object info if callback function is invalid	2023-09-13 22:29:12 +02:00
srcutree.c	srcu: Explain why callbacks invocations can't run concurrently	2023-12-12 02:41:17 +05:30
sync.c	rcu/sync: Use call_rcu_hurry() instead of call_rcu	2022-11-29 14:04:33 -08:00
tasks.h	rcu-tasks: Mark RCU Tasks accesses to current->rcu_tasks_idle_cpu	2023-12-12 02:22:47 +05:30
tiny.c	rcu: Dump memory object info if callback function is invalid	2023-09-13 22:29:12 +02:00
tree.c	rcu/exp: Handle RCU expedited grace period kworker allocation failure	2024-03-26 18:16:27 -04:00
tree.h	rcu/tree: Defer setting of jiffies during stall reset	2023-09-11 22:36:40 +02:00
tree_exp.h	rcu/exp: Handle RCU expedited grace period kworker allocation failure	2024-03-26 18:16:27 -04:00
tree_nocb.h	rcu/nocb: Fix WARN_ON_ONCE() in the rcu_nocb_bypass_lock()	2024-04-13 13:10:04 +02:00
tree_plugin.h	rcu: Mark additional concurrent load from ->cpu_no_qs.b.exp	2023-05-11 13:42:39 -07:00
tree_stall.h	rcu: Restrict access to RCU CPU stall notifiers	2023-12-12 02:31:22 +05:30
update.c	rcu: Restrict access to RCU CPU stall notifiers	2023-12-12 02:31:22 +05:30