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[46.135.95.94]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-ab6e47d06e5sm1167625566b.63.2025.02.05.11.32.58 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 05 Feb 2025 11:33:01 -0800 (PST) From: Mateusz Guzik To: ebiederm@xmission.com, oleg@redhat.com Cc: brauner@kernel.org, akpm@linux-foundation.org, Liam.Howlett@oracle.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Mateusz Guzik Subject: [PATCH v4 3/5] pid: sprinkle tasklist_lock asserts Date: Wed, 5 Feb 2025 20:32:19 +0100 Message-ID: <20250205193221.402150-4-mjguzik@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20250205193221.402150-1-mjguzik@gmail.com> References: <20250205193221.402150-1-mjguzik@gmail.com> MIME-Version: 1.0 X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 4EAF4180010 X-Stat-Signature: kmh3qwfew3wujzxaz8ucqm69f66ffu4q X-Rspam-User: X-HE-Tag: 1738783983-590091 X-HE-Meta: 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 MVWOF0TT ZWRQ66ZE5Dv0c3FiDaRoXX+PjA9ze1/x/1FKvWP8sIQMv+rGNc2OTiTHb+1n6soT9wO05TYVJuGi0iuUUEQqo0z0o2PBkGc6WgUTuvGh3Ye/uLWuwaOwvrtYmDYcCqUV16NoBHj6sGWbASQmgQs3fjavl+aaYmmDLFVVlflYz65wDca1vAS+tlV8izSLOtDktn+RDasvuM6Exat6byJDjxE+s6Lr9KXfANayovmg8EzTBZecnqu89VPUeKkSV737dZYmHbCnqLlFZSgw3NLVGIMNR7duGAVMPoPW86zTKeawYWLPp2hyQ4dyZnTbNd+Kk3o8msu4IzvbhdtVhn1rBNo3/yrpcwplczDyeicLf59eIqEvbZOXj0c2u3GYayAbfmUlyrOeR4idcJtYRIrCw9fd3jUWbTbzX4RhnbiahWMMXbJRMPOJ0t84S1Dc5jGiBkwxU X-Bogosity: Ham, tests=bogofilter, spamicity=0.000156, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Reviewed-by: Oleg Nesterov Signed-off-by: Mateusz Guzik --- kernel/pid.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/kernel/pid.c b/kernel/pid.c index 924084713be8..2ae872f689a7 100644 --- a/kernel/pid.c +++ b/kernel/pid.c @@ -339,17 +339,23 @@ static struct pid **task_pid_ptr(struct task_struct *task, enum pid_type type) */ void attach_pid(struct task_struct *task, enum pid_type type) { - struct pid *pid = *task_pid_ptr(task, type); + struct pid *pid; + + lockdep_assert_held_write(&tasklist_lock); + + pid = *task_pid_ptr(task, type); hlist_add_head_rcu(&task->pid_links[type], &pid->tasks[type]); } static void __change_pid(struct task_struct *task, enum pid_type type, struct pid *new) { - struct pid **pid_ptr = task_pid_ptr(task, type); - struct pid *pid; + struct pid **pid_ptr, *pid; int tmp; + lockdep_assert_held_write(&tasklist_lock); + + pid_ptr = task_pid_ptr(task, type); pid = *pid_ptr; hlist_del_rcu(&task->pid_links[type]); @@ -386,6 +392,8 @@ void exchange_tids(struct task_struct *left, struct task_struct *right) struct hlist_head *head1 = &pid1->tasks[PIDTYPE_PID]; struct hlist_head *head2 = &pid2->tasks[PIDTYPE_PID]; + lockdep_assert_held_write(&tasklist_lock); + /* Swap the single entry tid lists */ hlists_swap_heads_rcu(head1, head2); @@ -403,6 +411,7 @@ void transfer_pid(struct task_struct *old, struct task_struct *new, enum pid_type type) { WARN_ON_ONCE(type == PIDTYPE_PID); + lockdep_assert_held_write(&tasklist_lock); hlist_replace_rcu(&old->pid_links[type], &new->pid_links[type]); }