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bh=iUfaeCF69Nkp/7VspLJNX3subJ+K5BfO1gas842MLb8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=H8FRPy2qNoTKzxtpc7RlnD1OVR7cuEo2NLTc+m75ifE/yaBYm6jotUNMrwbH/dwlH JFH/newSJ7oLWf4qc9dggeU2UUzVtSLZZv4gPJAdQaUGuOfPNx93PMhRah+v63UUC2 AU+Mx0kM2ZoxZUoHHI0oogq+AGiyBcIXJWR/GhrNz99jNRmx+eFwqpigU6tUYu9f0w FU7GXZeMIT860jHe3Hy7kZK2wqV+N9e1ZJ2QsAok/YuRxMTb6q1qKd+9j6PSULPSfC OBL5We/ItwuaNruJJeRZMZyXCDoDyXIUN36/cmzMtY0rzDNTz/4qf4xinqWntMRXxx rx8zsM4E6JEfw== From: Frederic Weisbecker To: LKML Cc: Frederic Weisbecker , Christoph Lameter , Dennis Zhou , Marco Crivellari , Michal Hocko , Peter Zijlstra , Tejun Heo , Thomas Gleixner , Vlastimil Babka , Waiman Long , linux-mm@kvack.org Subject: [PATCH 12/27] cpu: Provide lockdep check for CPU hotplug lock write-held Date: Fri, 20 Jun 2025 17:22:53 +0200 Message-ID: <20250620152308.27492-13-frederic@kernel.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250620152308.27492-1-frederic@kernel.org> References: <20250620152308.27492-1-frederic@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 1F3A840013 X-Stat-Signature: ugo1qyeyfmykbffq1yhteisqh5gqo7sq X-Rspam-User: X-HE-Tag: 1750433027-246920 X-HE-Meta: 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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 --- 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 069fce6c7eae..ccf11a17c7fd 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -533,6 +533,11 @@ 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) -- 2.48.1