From patchwork Thu Mar 20 16:51:03 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stanislav Fomichev X-Patchwork-Id: 14024173 X-Patchwork-Delegate: kuba@kernel.org Received: from mail-pl1-f172.google.com (mail-pl1-f172.google.com [209.85.214.172]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6D61321D3E2; Thu, 20 Mar 2025 16:51:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.172 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742489467; cv=none; b=eVPIFHd6gF6PIUD0c41RD2Yune3hi7OKu6nvT9e5IV29F1HQVXLY+slnGvbvBRPRpQ2Wcw/KQLU8gpjiSkQw/to9CHxZ88xQ9bZFnM5cYmnVTxm0iLrAnG+rrYnK23QA2NwE9mkpow1o+kZMUF8/TpKjejxbkOEveNB/JGdLlrc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742489467; c=relaxed/simple; bh=96XACga2vRXvHJIb8ALHCPTfpdziK3WvQkZ4PbiQkhQ=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=KQb+eMGpwQBFgmfxzsRKAaRudITv9bdQYpTv214RPtYPLPsNFrQajn9WRld3ymHc309ZI73yZPwbjlL1+OfyWpxE4BvtQpyvBKnMfXc8acdnUj/+jHrMO+eEvt7Ao8pOc/mxkF39MJmO3t2NXpED8FMJmpjqC0foNJd0IWITf9A= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=fomichev.me; spf=pass smtp.mailfrom=gmail.com; arc=none smtp.client-ip=209.85.214.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=fomichev.me Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Received: by mail-pl1-f172.google.com with SMTP id d9443c01a7336-224019ad9edso25885085ad.1; Thu, 20 Mar 2025 09:51:05 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1742489464; x=1743094264; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=ePOhuEBOuQw7EEF85BsUnrOhaZqLyrnFAXA4BOdYNfM=; b=LIg77Nb7pgHJ9fnGduXiDoY8RoBQcrjBfmWJgLpIlZRFKlx6B0Ia8j1jNDOq2LvC35 FItJy4DP7CZ+ULT/LFmcJNNN8tzwaP5uO/vc7BIr+S17Ivl13rZt4SVIANimN36/EGsk QNL5bsORGyns1UM32fJ6gwMdfcmzTPuBymd9pdYnljFJwKKG8dDE8rtFTy4/hBG6Tsug o5hlq1UP//fCXT1RbMpdfw+myZ1jtaTifGqdmxAXxNHsIY+5f4eIUooum4fqLSwoOz9F Ir9i5A3e1AIOHjFelGt5gbvHiM3xRoYjZdoxhxdVjzzCfFzhF0DVOApsXhElwvHqHULt 32Yg== X-Forwarded-Encrypted: i=1; AJvYcCWd0eN6NIkCo1uouMrhtF0SvIu9f2K1EOdkHJqhuvlY+nnfps/CK1N83xvE7S/1O9B/lGFS3bezAEEAkDY=@vger.kernel.org X-Gm-Message-State: AOJu0Yy0OtYceG77qPXlthHL+rdxoqylCHHffDOK6O6tfMEg0AFgRL94 hfwIXNUcfbcZspLnMiWGgXcg/q9HjCyH3f1LiMU2iqMMs5Fy3wsAZiol X-Gm-Gg: ASbGncsZdIKlf8gT90NYmKohSHPqCdlpX35z314to1a6r9w0jdCZLJzg6DRcHcIMKrU R0V5Ib2Jug+t59hu5I4o+lxjCgxKC+VykLFTri+b7FpqF2lFpmoGXzWMeLq4FPqgs0x6tGxO+Ud jqeJMtCXZgQzJEgBhyaTdtxy8gnkvEoiUnk0+cnouT+QWa5h+ab2MksUuapg5RPsy8vORRfwI+X tdDZeocWp+n5DfBX6iS0gNWdQudP58qnzZSPxqxKwTG63saQ9OFsGXJcn6hfb/In3C14+t9F1+n ZS1fLn6TMcjF7YK+wSOAdchEdj2OVNF6nsihGitWQ5TH X-Google-Smtp-Source: AGHT+IFym2XBNm7BhSm1aJW6/nPpOwI8L8IRO0TBiReykeX9o8xWnc5WrTdklEthGTQ+1cbQkL/a3Q== X-Received: by 2002:a05:6a00:179b:b0:736:52d7:daca with SMTP id d2e1a72fcca58-73905a2a062mr276066b3a.18.1742489464166; Thu, 20 Mar 2025 09:51:04 -0700 (PDT) Received: from localhost ([2601:646:9e00:f56e:123b:cea3:439a:b3e3]) by smtp.gmail.com with UTF8SMTPSA id d2e1a72fcca58-73905fab82esm9448b3a.14.2025.03.20.09.51.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 20 Mar 2025 09:51:03 -0700 (PDT) From: Stanislav Fomichev To: netdev@vger.kernel.org Cc: davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, linux-kernel@vger.kernel.org, jhs@mojatatu.com, xiyou.wangcong@gmail.com, jiri@resnulli.us, horms@kernel.org, sdf@fomichev.me Subject: [PATCH net-next v2] net: hold netdev reference during qdisc_create request_module Date: Thu, 20 Mar 2025 09:51:03 -0700 Message-ID: <20250320165103.3926946-1-sdf@fomichev.me> X-Mailer: git-send-email 2.48.1 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: kuba@kernel.org Eric reports that by the time we call netdev_lock_ops after rtnl_unlock/rtnl_lock, the dev might point to an invalid device. Add extra dev_hold/dev_put to make sure the device pointer is still valid after rtnl_unlock. Fixes: a0527ee2df3f ("net: hold netdev instance lock during qdisc ndo_setup_tc") Reported-by: Eric Dumazet Link: https://lore.kernel.org/netdev/20250305163732.2766420-1-sdf@fomichev.me/T/#me8dfd778ea4c4463acab55644e3f9836bc608771 Signed-off-by: Stanislav Fomichev --- net/sched/sch_api.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c index aef39f6dc6a8..85ddb811780c 100644 --- a/net/sched/sch_api.c +++ b/net/sched/sch_api.c @@ -1280,11 +1280,13 @@ static struct Qdisc *qdisc_create(struct net_device *dev, * We replay the request because the device may * go away in the mean time. */ + dev_hold(dev); netdev_unlock_ops(dev); rtnl_unlock(); request_module(NET_SCH_ALIAS_PREFIX "%s", name); rtnl_lock(); netdev_lock_ops(dev); + dev_put(dev); ops = qdisc_lookup_ops(kind); if (ops != NULL) { /* We will try again qdisc_lookup_ops,