rcu_read_lock_trace(9)

hey bestie!! welcome to the rcu_read_lock_trace(9) page in the Kernel API Manual ✨ this one is short but iconic, so grab your lil drink and let’s go 🧋💅

💖 NAME 💖

• rcu_read_lock_trace — mark beginning of RCU-trace read-side critical section 💅

🦋 SYNOPSIS 🦋

void rcu_read_lock_trace (void );

🎀 ARGUMENTS 🎀

• void — no arguments. literally none, not even a tiny one 🙈

🌸 DESCRIPTION 🌸

okay so here’s the tea ☕: when synchronize_rcu_tasks_trace is invoked by one task, then that task is guaranteed to block until all other tasks exit their read-side critical sections. no cap, it waits for everybody to finish. 💅

Similarly, if call_rcu_trace is invoked on one task while other tasks are within RCU read-side critical sections, invocation of the corresponding RCU callback is deferred until after all the other tasks exit their critical sections. it’s giving patience, honestly 🫶

For more details, please see the documentation for rcu_read_lock. 💖

💜 SEE ALSO 💜

• Kernel file ./include/linux/rcupdate_trace.h
• rcu_read_lock_tasks_trace(9)
• rcu_read_unlock_tasks_trace(9)
• rcu_read_unlock_trace(9)
• call_rcu_tasks_trace(9)
• synchronize_rcu_tasks_trace(9)
• rcu_barrier_tasks_trace(9)
• rcu_tasks_trace_expedite_current(9)

mwah 💋 okay bye bestie! this page’s source/version is ./include/linux, it’s dated October 2026, and it’s literally rcu_read_lock_trace(9). periodt 🎀✨