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 A8CC53D55F; Mon, 18 Dec 2023 12:45:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="olVWplEs" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 46598C433C9; Mon, 18 Dec 2023 12:45:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1702903501; bh=wEAQwEs3TAqhqtbRz+sEjGpOSuDxnPLkYICZfklPgaw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=olVWplEs8AzhhGX7UP8qsYczUh0kqfu4Evct6l0rISTMwdtUa5olpmtPstFLsnUwX F1yvHTo0hNxAN12aHA+Ic2+qzqI0TXzAjtKPsan6ti3jSrcIUrXOx9l0m4uzRROk6j 0ubV0c19XJC9GlRcpARlDhxbo4ziGwfQbFW181KisTT2FtTBSSdzCrfX9IQE+E0guS NzOI9PznoM8b3XagXvimUD61r76JR7a4wCTVRBPB18ZyV8FLCZMILLiARUUSZDpGfD aixAlHPACz1t2fFkhiFGnhZp//+YJNjPwENxzoSjtnpcr2Blm2umOfR/JERJJGVZ1R //mHf1zLPKH4Q== 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 6.6 18/18] ring-buffer: Do not record in NMI if the arch does not support cmpxchg in NMI Date: Mon, 18 Dec 2023 07:43:52 -0500 Message-ID: <20231218124415.1379060-18-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20231218124415.1379060-1-sashal@kernel.org> References: <20231218124415.1379060-1-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 6.6.7 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 f1ef4329343bf..30c8d01a4d08b 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -3714,6 +3714,12 @@ rb_reserve_next_event(struct trace_buffer *buffer, int nr_loops = 0; int add_ts_default; + /* 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); /* The commit page can not change after this */ -- 2.43.0