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 468A4214811; Mon, 3 Mar 2025 16:31:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741019492; cv=none; b=QL9SJKdRFS9ueErCcqLiNc42bFbg6nWzmSY+NC2H3wT0TRspNYb0ntUksDWFz1ermxmGPFqA6Spto7yaoFGgAwoaC8Sca6rZF9ZNwfxRSus2nFi0CVcBS3lzY907XMKBhA4oPMUIP9efXDoWlMoWk0YXDn887vGQ72A3j+fPK28= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741019492; c=relaxed/simple; bh=3VrgwIKxT1ihqRIYNVWrnRqlFz1S310SQYF7dCx30aY=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=Ra6xxibpa5lJ0fU57uokIXdBPMFtiHrp6c+z1dbsKp20lnECAwLPNOPCO1WH+HUF/nwaLQQrJuoAyv1l+t0BYuXAc4PmOtqkiJChWJjspTiluhcrjI/NGYtWaO8BzcBvBQOlrJC5gNVxgYDxhkDtHPxgo0KGf7+crgBJtYdpSrA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=O30M/Vgf; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="O30M/Vgf" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1986BC4CED6; Mon, 3 Mar 2025 16:31:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1741019491; bh=3VrgwIKxT1ihqRIYNVWrnRqlFz1S310SQYF7dCx30aY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=O30M/VgfiRpvXTL0UBtAYOQX+Cm3gZW92B8lk6oqxazdbT37skiqcQeG5k4ZtnWtj qvVeWelpihkfF76RNsjN+d9MkJM3kldUJfyQroD14Dza++f+AuYn9wucxYyPWauvfD mOsEQ+L0rH7SjeEgRPBw8ysMPquVHlOoyaYSKnYCAWqIVv04V69gKrRXtinBHur1Hh xDvl74WwnstTgexQkL3mNdu1mUDOjSAgWqOyi1XZTjgW6cAyoVojCY5dluxoG0FP8j cIq/1ol+QnU7B6Yw22jIfjFS8z9VEnQ5BonWWmrqnE9JANjMA79RMiKaBrtUuuCrSj YpzscFzi0aq/Q== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Frederic Weisbecker , Paul Menzel , Jakub Kicinski , Francois Romieu , Breno Leitao , Eric Dumazet , Sasha Levin , davem@davemloft.net, pabeni@redhat.com, kuniyu@amazon.com, bigeasy@linutronix.de, jdamato@fastly.com, aleksander.lobakin@intel.com, netdev@vger.kernel.org Subject: [PATCH AUTOSEL 6.6 10/11] net: Handle napi_schedule() calls from non-interrupt Date: Mon, 3 Mar 2025 11:31:08 -0500 Message-Id: <20250303163109.3763880-10-sashal@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250303163109.3763880-1-sashal@kernel.org> References: <20250303163109.3763880-1-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 6.6.80 Content-Transfer-Encoding: 8bit From: Frederic Weisbecker [ Upstream commit 77e45145e3039a0fb212556ab3f8c87f54771757 ] napi_schedule() is expected to be called either: * From an interrupt, where raised softirqs are handled on IRQ exit * From a softirq disabled section, where raised softirqs are handled on the next call to local_bh_enable(). * From a softirq handler, where raised softirqs are handled on the next round in do_softirq(), or further deferred to a dedicated kthread. Other bare tasks context may end up ignoring the raised NET_RX vector until the next random softirq handling opportunity, which may not happen before a while if the CPU goes idle afterwards with the tick stopped. Such "misuses" have been detected on several places thanks to messages of the kind: "NOHZ tick-stop error: local softirq work is pending, handler #08!!!" For example: __raise_softirq_irqoff __napi_schedule rtl8152_runtime_resume.isra.0 rtl8152_resume usb_resume_interface.isra.0 usb_resume_both __rpm_callback rpm_callback rpm_resume __pm_runtime_resume usb_autoresume_device usb_remote_wakeup hub_event process_one_work worker_thread kthread ret_from_fork ret_from_fork_asm And also: * drivers/net/usb/r8152.c::rtl_work_func_t * drivers/net/netdevsim/netdev.c::nsim_start_xmit There is a long history of issues of this kind: 019edd01d174 ("ath10k: sdio: Add missing BH locking around napi_schdule()") 330068589389 ("idpf: disable local BH when scheduling napi for marker packets") e3d5d70cb483 ("net: lan78xx: fix "softirq work is pending" error") e55c27ed9ccf ("mt76: mt7615: add missing bh-disable around rx napi schedule") c0182aa98570 ("mt76: mt7915: add missing bh-disable around tx napi enable/schedule") 970be1dff26d ("mt76: disable BH around napi_schedule() calls") 019edd01d174 ("ath10k: sdio: Add missing BH locking around napi_schdule()") 30bfec4fec59 ("can: rx-offload: can_rx_offload_threaded_irq_finish(): add new function to be called from threaded interrupt") e63052a5dd3c ("mlx5e: add add missing BH locking around napi_schdule()") 83a0c6e58901 ("i40e: Invoke softirqs after napi_reschedule") bd4ce941c8d5 ("mlx4: Invoke softirqs after napi_reschedule") 8cf699ec849f ("mlx4: do not call napi_schedule() without care") ec13ee80145c ("virtio_net: invoke softirqs after __napi_schedule") This shows that relying on the caller to arrange a proper context for the softirqs to be handled while calling napi_schedule() is very fragile and error prone. Also fixing them can also prove challenging if the caller may be called from different kinds of contexts. Therefore fix this from napi_schedule() itself with waking up ksoftirqd when softirqs are raised from task contexts. Reported-by: Paul Menzel Reported-by: Jakub Kicinski Reported-by: Francois Romieu Closes: https://lore.kernel.org/lkml/354a2690-9bbf-4ccb-8769-fa94707a9340@molgen.mpg.de/ Cc: Breno Leitao Signed-off-by: Frederic Weisbecker Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20250223221708.27130-1-frederic@kernel.org Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/core/dev.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/core/dev.c b/net/core/dev.c index 8c30cdcf05d4b..c31a7f7bedf3d 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -4532,7 +4532,7 @@ static inline void ____napi_schedule(struct softnet_data *sd, * we have to raise NET_RX_SOFTIRQ. */ if (!sd->in_net_rx_action) - __raise_softirq_irqoff(NET_RX_SOFTIRQ); + raise_softirq_irqoff(NET_RX_SOFTIRQ); } #ifdef CONFIG_RPS -- 2.39.5