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 CD24C1370; Sat, 13 Jul 2024 00:45:43 +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=1720831543; cv=none; b=bvcrGrpq9E4W5aqHpYhhAP//y50u6QPcWJ4tTN3wvoo5+H0BTb4u2VMTgzc/W29dXpMLntTYM7MfISqAjvrIb0851UstPR8cYfuy+4zqEbjyCS+/4wNxVYj6MqT2QxwoeIPwq9cU7dVD9Ky3SYU7TwhHH+28NEfxqrM2z1PhV4Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720831543; c=relaxed/simple; bh=JkYZvMvMjp2C3xzUtYG4+umluvBkVgq5RnDlPgh6Rb4=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=OGLxODwqro+J5ZPhwFVkHZ+4dEnnOkusB/Tg3RaB84nNKLAGBYJCKE6iMpLRjcjptb+9oAZ+gih16Ex8UP/LMnKQBiFTFnUbBD6dGDbhL3nRHG9traAKmdrY+8byFNjRHg+JqLkZ7CcrDvAiy+hei87Und7WRMjh+8zVGMfB/bo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=pNI+l+jV; 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="pNI+l+jV" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E24ECC32782; Sat, 13 Jul 2024 00:45:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1720831543; bh=JkYZvMvMjp2C3xzUtYG4+umluvBkVgq5RnDlPgh6Rb4=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=pNI+l+jVLQO2ZHHD7Qzqzrlqal8WL3jR6TNRjk/oHLPkPnLi3dXIhH86TubC3Inas Uml1r8bnNRNacJIpqTRtLmv6FPA/hK9Yq3Y9RWMWmkiaKzLGJ5XrzrzUN7jR6h7ubv PpNIqgeNXlP5XElAz9oFXBGH65rB24tTZIMhBJP+vYG3lykmn2hVI6scoSqq2KveCc QnzSRTJKc1FL9kjTIFoQaU5fyL28qh520mra8c7JS7Vqiuagxkwt22TQ3GR1vT1IZe k7QnpM8/M7EaUssqw1fN0qflrwPYkOZNNNkjxKgqqj5DNoftVCeA4EwD5FAKxNiLqS joFcuJD4/t0KA== Date: Fri, 12 Jul 2024 17:45:42 -0700 From: Jakub Kicinski To: Breno Leitao Cc: "Michael S. Tsirkin" , Jason Wang , Xuan Zhuo , Eugenio =?UTF-8?B?UMOpcmV6?= , "David S. Miller" , Eric Dumazet , Paolo Abeni , rbc@meta.com, horms@kernel.org, virtualization@lists.linux.dev (open list:VIRTIO CORE AND NET DRIVERS), netdev@vger.kernel.org (open list:NETWORKING DRIVERS), linux-kernel@vger.kernel.org (open list) Subject: Re: [PATCH net-next] virtio_net: Fix napi_skb_cache_put warning Message-ID: <20240712174542.4e84508f@kernel.org> In-Reply-To: <20240712115325.54175-1-leitao@debian.org> References: <20240712115325.54175-1-leitao@debian.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Fri, 12 Jul 2024 04:53:25 -0700 Breno Leitao wrote: > After the commit bdacf3e34945 ("net: Use nested-BH locking for > napi_alloc_cache.") was merged, the following warning began to appear: > > WARNING: CPU: 5 PID: 1 at net/core/skbuff.c:1451 napi_skb_cache_put+0x82/0x4b0 > > __warn+0x12f/0x340 > napi_skb_cache_put+0x82/0x4b0 > napi_skb_cache_put+0x82/0x4b0 > report_bug+0x165/0x370 > handle_bug+0x3d/0x80 > exc_invalid_op+0x1a/0x50 > asm_exc_invalid_op+0x1a/0x20 > __free_old_xmit+0x1c8/0x510 > napi_skb_cache_put+0x82/0x4b0 > __free_old_xmit+0x1c8/0x510 > __free_old_xmit+0x1c8/0x510 > __pfx___free_old_xmit+0x10/0x10 > > The issue arises because virtio is assuming it's running in NAPI context > even when it's not, such as in the netpoll case. > > To resolve this, modify virtnet_poll_tx() to only set NAPI when budget > is available. Same for virtnet_poll_cleantx(), which always assumed that > it was in a NAPI context. > > Fixes: df133f3f9625 ("virtio_net: bulk free tx skbs") > Suggested-by: Jakub Kicinski > Signed-off-by: Breno Leitao Reviewed-by: Jakub Kicinski