[PATCH 11/33] cpu: Provide lockdep check for CPU hotplug lock write-held
From: Frederic Weisbecker <frederic@kernel.org>
Date: 2026-01-01 22:15:45
Also in:
cgroups, linux-arm-kernel, linux-block, linux-mm, linux-pci, lkml
Subsystem:
cpu hotplug, per-cpu memory allocator, the rest · Maintainers:
Thomas Gleixner, Peter Zijlstra, Dennis Zhou, Tejun Heo, Christoph Lameter, Linus Torvalds
cpuset modifies partitions, including isolated, while holding the cpu hotplug lock read-held. This means that write-holding the CPU hotplug lock is safe to synchronize against housekeeping cpumask changes. Provide a lockdep check to validate that. Signed-off-by: Frederic Weisbecker <frederic@kernel.org> --- include/linux/cpuhplock.h | 1 + include/linux/percpu-rwsem.h | 1 + kernel/cpu.c | 5 +++++ 3 files changed, 7 insertions(+)
diff --git a/include/linux/cpuhplock.h b/include/linux/cpuhplock.h
index f7aa20f62b87..286b3ab92e15 100644
--- a/include/linux/cpuhplock.h
+++ b/include/linux/cpuhplock.h@@ -13,6 +13,7 @@ struct device; extern int lockdep_is_cpus_held(void); +extern int lockdep_is_cpus_write_held(void); #ifdef CONFIG_HOTPLUG_CPU void cpus_write_lock(void);
diff --git a/include/linux/percpu-rwsem.h b/include/linux/percpu-rwsem.h
index 288f5235649a..c8cb010d655e 100644
--- a/include/linux/percpu-rwsem.h
+++ b/include/linux/percpu-rwsem.h@@ -161,6 +161,7 @@ extern void percpu_free_rwsem(struct percpu_rw_semaphore *); __percpu_init_rwsem(sem, #sem, &rwsem_key); \ }) +#define percpu_rwsem_is_write_held(sem) lockdep_is_held_type(sem, 0) #define percpu_rwsem_is_held(sem) lockdep_is_held(sem) #define percpu_rwsem_assert_held(sem) lockdep_assert_held(sem)
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 40b8496f47c5..01968a5c4a16 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c@@ -534,6 +534,11 @@ int lockdep_is_cpus_held(void) { return percpu_rwsem_is_held(&cpu_hotplug_lock); } + +int lockdep_is_cpus_write_held(void) +{ + return percpu_rwsem_is_write_held(&cpu_hotplug_lock); +} #endif static void lockdep_acquire_cpus_lock(void)
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2.51.1