From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0E7114AF168; Fri, 11 Sep 2026 18:16:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789150583; cv=none; b=O8mqv3flSk9bZ6cALKdGAiM7wXnCmbROgnxHtwdN0TQ7av3WWJw6Ic7ioIVK3zOM8fpgX0Gd7cDSb5HrbCvztut9zNQNYmXrlhfSo9MDFEfVM/wdn7Meh+63bXV+dICKgcW55m6V3/q3855Nrl8JQ8Hhzq31VjpaEv0oipWCf38= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789150583; c=relaxed/simple; bh=ZNK7lfuT09qSARdbt1/cZs7gniyWCRs5j7azukBwUOg=; h=Message-ID:Date:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=gMh4tX8leXC/cZl+2SS71r/lnFJnKHs7CF2hWdvjaViVFXX9BCE2L/1gZ2WpWArl5AfUDaPtCUzQeWZ6tyW0+hTGmwaq0tm6bZmHCdZiuXdA2ktIJNiO2H42YiXC4u7UG5euB1lkwc52M4mWkr7NevaIDJC0mfsSxY2RCGx7Dt8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=b1hkwYvr; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="b1hkwYvr" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CFDCE1F008BC; Fri, 11 Sep 2026 18:16:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789150570; bh=BW1arZP/jeW3t4WrRP5pr3VhcnT2T+SZnRTRC8idGJU=; h=Date:From:To:Cc:Subject:References; b=b1hkwYvrOmimg5y9V1j7so/Lrw/XPUACCW4TWvX9q2Z8X8Xo3B6MuUTi55Ah+HbGZ Pn/ExFu9U6tBSd+tPqY28cxJMy7JmHSHNijc/3c2zG0iDT7HaaMnZuXmzxdViaYSef spq6mZ3CIG3cbpIFR/o4rDzObTkv0nkr3i1Lk758rd3h8XE7VjQ7sK93rd149RE1B7 bY+esHnR1/d3TCWMZ+sOtaQBCZJMdpCLIj9F5gcNa8na+I2018fSPEywLm22ECiLNb op+GvTNdvTuxstafSwtdaj8WfAnBn1bZi8fDeP5Z+//idLNmz4HCflcI5qLrleTm6U V490Hv268vN/w== Received: from rostedt by gandalf with local (Exim 4.99.4) (envelope-from ) id 1x55oa-0000000955h-1lP9; Fri, 11 Sep 2026 14:17:32 -0400 Message-ID: <20260911181732.227965353@kernel.org> User-Agent: quilt/0.69 Date: Fri, 11 Sep 2026 14:16:56 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers , Andrew Morton , stable@vger.kernel.org, Vincent Donnefort , Sebastian Andrzej Siewior Subject: [for-linus][PATCH 20/20] ring-buffer: Acquire the lock with irqsave in rb_wake_up_waiters() References: <20260911181636.485043797@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 From: Sebastian Andrzej Siewior 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 Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Steven Rostedt --- kernel/trace/ring_buffer.c | 13 ++++++------- 1 file 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); } -- 2.53.0