From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 C38FD12875C; Mon, 18 Dec 2023 12:47:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="vQv1OeHb" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8617CC433CB; Mon, 18 Dec 2023 12:47:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1702903643; bh=rKso6YWkWl1RNRQih0vmpvNpO29N4ATAAdlBKIb6p+4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=vQv1OeHb3X4CQYY1ZxFnzEOSzFEcsA5kMzjvkBZKym5Bt43IVSAI8OxqF23MMYhxi I4qyX87EK7MdApCOOLwz9iyo5mbhMJPAVAbz93SEycZVYq1V+VLKOoUxik4eAdv1oM r6pS1GtfMJdI808JkoWDEhFW7Cyw51g7+yLu1hKIS4Lz00KAytTZhfSaIShfQAcRgw +lCHR0xpLPCKoZxlROV8zFuZhHWeUu19qQuPRm5LtKO8BbGoWsCaz1F0HoDD6d1A98 4z2UWPsXIb+4pFYED7AhJ1BruOAX+nBnjokvs6JTLO3JT1afaDDYzLRLMmOULblqSH OK+AuYh8dDCaA== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: "Steven Rostedt (Google)" , Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers , Sasha Levin , linux-trace-kernel@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 6/6] ring-buffer: Do not record in NMI if the arch does not support cmpxchg in NMI Date: Mon, 18 Dec 2023 07:47:11 -0500 Message-ID: <20231218124713.1382373-6-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20231218124713.1382373-1-sashal@kernel.org> References: <20231218124713.1382373-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 4.19.302 Content-Transfer-Encoding: 8bit From: "Steven Rostedt (Google)" [ Upstream commit 712292308af2265cd9b126aedfa987f10f452a33 ] As the ring buffer recording requires cmpxchg() to work, if the architecture does not support cmpxchg in NMI, then do not do any recording within an NMI. Link: https://lore.kernel.org/linux-trace-kernel/20231213175403.6fc18540@gandalf.local.home Cc: Masami Hiramatsu Cc: Mark Rutland Cc: Mathieu Desnoyers Signed-off-by: Steven Rostedt (Google) Signed-off-by: Sasha Levin --- kernel/trace/ring_buffer.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 320aa60664dc9..efa11c638c841 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -2889,6 +2889,12 @@ rb_reserve_next_event(struct ring_buffer *buffer, int nr_loops = 0; u64 diff; + /* ring buffer does cmpxchg, make sure it is safe in NMI context */ + if (!IS_ENABLED(CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG) && + (unlikely(in_nmi()))) { + return NULL; + } + rb_start_commit(cpu_buffer); #ifdef CONFIG_RING_BUFFER_ALLOW_SWAP -- 2.43.0