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| author | Sebastian Andrzej Siewior <bigeasy@linutronix.de> | 2026-09-11 12:21:52 +0200 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2026-09-11 14:09:42 -0400 |
| commit | 815e07c8fe885a87751c2496a30ae0dcd4118210 (patch) | |
| tree | ac96bc0eaeab706e445fd000af0c2cdbd59f6f9b | |
| parent | ed0aff60f83a9bdc2f6556376ac79c96b3ce7e80 (diff) | |
| download | linux-next-815e07c8fe885a87751c2496a30ae0dcd4118210.tar.gz linux-next-815e07c8fe885a87751c2496a30ae0dcd4118210.zip | |
ring-buffer: Acquire the lock with irqsave in rb_wake_up_waiters()
rb_wake_up_waiters() is a irq_work callback which is initialized with
init_irq_work(). As such it will be invoked in thread context on
PREEMPT_RT. Invoking the callback in IRQ context on PREEMPT_RT is not an
option due its usage of wake_up_all(). Since this callback may run in
thread context, it needs to acquire ring_buffer_per_cpu::reader_lock with
disabling interrupts and may not assume that they are disabled.
Use raw_spinlock_irqsave() to acquire ring_buffer_per_cpu::reader_lock.
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260911102152.YEtwkBj9@linutronix.de
Fixes: 68282dd930ea3 ("ring-buffer: Fix resetting of shortest_full")
Reviewed-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| -rw-r--r-- | kernel/trace/ring_buffer.c | 13 |
1 files changed, 6 insertions, 7 deletions
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 0e30c7bd6045..9bc8ce8c5676 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -904,14 +904,13 @@ static void rb_wake_up_waiters(struct irq_work *work) struct ring_buffer_per_cpu *cpu_buffer = container_of(rbwork, struct ring_buffer_per_cpu, irq_work); - /* Called from interrupt context */ - raw_spin_lock(&cpu_buffer->reader_lock); - rbwork->wakeup_full = false; - rbwork->full_waiters_pending = false; + scoped_guard(raw_spinlock_irqsave, &cpu_buffer->reader_lock) { + rbwork->wakeup_full = false; + rbwork->full_waiters_pending = false; - /* Waking up all waiters, they will reset the shortest full */ - cpu_buffer->shortest_full = 0; - raw_spin_unlock(&cpu_buffer->reader_lock); + /* Waking up all waiters, they will reset the shortest full */ + cpu_buffer->shortest_full = 0; + } wake_up_all(&rbwork->full_waiters); } |