From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793208505; b=LeWlHkmr0mXUyQssTwdGF5zZLtWFFVmUTS0AolFKtzQUyoM/Cc+I+VxRxUSSjEyfarh/ q4lb+w/YtIYf/6i926e/1tsEaxDUytCCLywylnNvKvr6/i1GWPu5nzT7oCN3YDl30uNlP zegdA0o7IdVzV5JJWeZkKp7zd38lZOVtMlFbA5dyYfL+/ABunKRpNRfCcR/7LTlVJAfJD eHZhsbkj68+qLl0jKaLAAzo2QyBvf7huOXzUo9IbEt1tsKuV155vLesGVymUGBDYnzgnd EBrD5Y7o5ojTkAU6mQMcvjXVQvxQpjK4gs0p/NchQ7Qp06T1LvOz1CyLs0fJOrSxhGg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793208505; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=IVAlaHIe3ExAzkC6wIwzDUD9pjYTTzvLX9+0tyvS4bQ=; b=mWt3ccAZlunjNqVr4TO5waxN6/SlrFnHP+o2lK2euWd7KJR9BCQ0wclNlosueF2vh0xg bFaeH1N3PpoZ630/OeV7q4KFWXXaeFums9Sd4MUEhS60XgORiM7LWxvIL1UK5yigtWYZE DUxLnJ3NiY25yzK6weix2dM1mt+oiRdP1PeMR3Wui378T+qQrl9vYKq4UwtXaqNhaSRup O3+tRIOe46EMkIQCLfPv8yaviT2ZQWJV2jTa+aw8UzggsbOcA5cM0uXxLNvzvMRdsP+qR quFQmD/nCYdYr4VkZE6+QRSXBeOZRmKbPcI7sao2aGOl91p4y+qbxpL67iwV9smkj9Q== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=UICSRrG3; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5FC50606A31E; Wed, 28 Oct 2026 17:28:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=UICSRrG3 Received: by smtp.kernel.org (Postfix) with ESMTPSA id AFBAB1F01825; Wed, 28 Oct 2026 17:28:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793208505; bh=IVAlaHIe3ExAzkC6wIwzDUD9pjYTTzvLX9+0tyvS4bQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=UICSRrG37v2p8H1f66oK5X0X4rSHUEsAvq0M7phr8FePzQR9YeDpgeoZ8Ej7Th3gc L8GKwGu76sr4GwvuDVzqaUEdrK0wZwBvlbLX9+KHaj0MOSU6zuw0+xQwmE0FRm+L5v yWfSqhWNoZSkeQYKwWToiGO7L6zpaXGA7KsiwQIM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Vincent Donnefort , Sebastian Andrzej Siewior , Steven Rostedt , Sasha Levin Subject: [PATCH 5.10 100/516] ring-buffer: Acquire the lock with irqsave in rb_wake_up_waiters() Date: Wed, 28 Oct 2026 17:54:12 +0100 Message-ID: <20261028170005.890261689@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261028170003.522232767@linuxfoundation.org> References: <20261028170003.522232767@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Sebastian Andrzej Siewior [ Upstream commit 815e07c8fe885a87751c2496a30ae0dcd4118210 ] 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 [ Replaced scoped_guard() with explicit raw_spin_lock_irqsave()/raw_spin_unlock_irqrestore() calls for GNU89 compatibility. ] Signed-off-by: Sasha Levin --- kernel/trace/ring_buffer.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 1c1b4139c4726..0612ef61bf973 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -835,15 +835,15 @@ static void rb_wake_up_waiters(struct irq_work *work) /* Only cpu_buffer sets the above flags */ struct ring_buffer_per_cpu *cpu_buffer = container_of(rbwork, struct ring_buffer_per_cpu, irq_work); + unsigned long flags; - /* Called from interrupt context */ - raw_spin_lock(&cpu_buffer->reader_lock); + raw_spin_lock_irqsave(&cpu_buffer->reader_lock, flags); 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); + raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags); wake_up_all(&rbwork->full_waiters); } -- 2.53.0