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 029DB33B964; Thu, 6 Nov 2025 22:30:06 +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=1762468207; cv=none; b=KNf2ctDMsPH/g8sFNQzCiQiBRD97nac0SQPPZIzuNJqjM/mDZXVeijeit8y+u0UEd/Js/bDjauwaHN0ScRclT1Vh4IfTmCE+2wDGskir4WqFKRcLUDtM7c8fcLXgX+pY2a2dh8oMcUjC+WrXsxiUOA37d73H015QcL9HDDAF9Cc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762468207; c=relaxed/simple; bh=grgz70MrxjYE02neZOSjO46NidNyWXWXQVXB6qderrs=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=M4UVjmWAGkYaLxeJlT3xzs7bitiI4EpVQ7HwzpbstzwlikvTvZXSIzCV1r34vbgchiadI4oFDmpJ5Yc4XYwz52cQKwBDz9NzbMJeB+lRa9/Opqu9C1aa7rWidQ8QDP9b+e/LQMCXbfQgN46eBu5RU94aQ95b2MiebXZudJC7kbc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=pQfZOH8S; 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="pQfZOH8S" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C22BCC4CEF7; Thu, 6 Nov 2025 22:30:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1762468206; bh=grgz70MrxjYE02neZOSjO46NidNyWXWXQVXB6qderrs=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=pQfZOH8SEKQzmLDrtfnPo4yrX1IVp11TCu4VuBCWVDSTHw/Lmp8YY8wkXIR1eS2jg OzetIqGFm4L52hQwGUYeYsI49ip/oJzu2Qy1ASidZ8VeW/AX0z2u8zI/9nTzbfkCiM M3JJ5w+vMVMrTaCS4kDDWss9Off+mPxeMiogfAA0FgyK/1P860ah0itvE7lLdvkIwt iSjdIVgRnVonGTsT0+l11h+D9y4xnPhmXo2lKNkGlCedOwDsqp080aZoBdmSZGU23K c1FCltUiYDkAucmICAP89L/oLg1mKEQ+TDnxl/KIDF8JeZ7QMLIBgWO59fzoPKAoqi S0H8kSCO76sDA== Date: Thu, 6 Nov 2025 14:30:04 -0800 From: Jakub Kicinski To: Kuniyuki Iwashima Cc: syzbot+cif2d6d318f7e85f0b@syzkaller.appspotmail.com, davem@davemloft.net, edumazet@google.com, hoang.h.le@dektech.com.au, horms@kernel.org, jmaloy@redhat.com, kuni1840@gmail.com, netdev@vger.kernel.org, pabeni@redhat.com, syzbot@lists.linux.dev, syzbot@syzkaller.appspotmail.com, syzkaller-bugs@googlegroups.com, tipc-discussion@lists.sourceforge.net Subject: Re: [syzbot ci] Re: tipc: Fix use-after-free in tipc_mon_reinit_self(). Message-ID: <20251106143004.55f4f3fc@kernel.org> In-Reply-To: <20251106175926.686885-1-kuniyu@google.com> References: <690c6ca9.050a0220.1e8caa.00d2.GAE@google.com> <20251106175926.686885-1-kuniyu@google.com> 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 Thu, 6 Nov 2025 17:59:17 +0000 Kuniyuki Iwashima wrote: > -void tipc_mon_reinit_self(struct net *net) > +void tipc_mon_reinit_self(struct net *net, bool rtnl_held) > { > struct tipc_monitor *mon; > int bearer_id; > > - rtnl_lock(); > + if (!rtnl_held) > + rtnl_lock(); I haven't looked closely but for the record conditional locking is generally considered to be poor code design. Extract the body into a __tipc_mon_reinit_self() helper and call that when lock is already held? And: void tipc_mon_reinit_self(struct net *net) { rtnl_lock(); __tipc_mon_reinit_self(net); rtnl_unlock(); }