From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793620954; b=s1cQkgvxmwsikoVJyybHONHnT6fkIcsoRGpJFLoAFt+JwblNWaUy7ZxAuQXgIM0pGoGe 2LLSWUN7jlm6iy5OckjTpobIJNaGHQkq90zU+XULRW/73ETZS1mEZ3An4o+mPdLn7pWEu oUKjs9spm7htErsSSmyt0b5ClVAi3NeTnhNuamqdeUD46HpzDtvgs9a3vY2yTcB1X9+5Q 3w/fC6hXUQznU06902pGcEgBMW24GZ5pryiXXVgJBJ7X4jaBSkN2mHr9MoDs4oI7usQ3v tnSe977mjIMJOFD/FPnp8Qit4Cnlpo2eZbAfHWCm/mGgjsqlxOyi5TCV+ORV/qOT2sw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793620954; h=Received:DKIM-Signature:Date:From:To:Cc:Subject:Message-ID: References:MIME-Version:Content-Type:Content-Disposition:In-Reply-To; bh=Fr0PNZ8uIjWuUyi5jHRttjfJcgJHs22wa+3cbgmTv6Y=; b=03B3Fo0FMxRxAuyztvg2VT5NLMTfaOV7YoPAe6TkYuvFoUDRxoDbCg3cjgCedpMfabuR 5YUwZFUHRglGlSyevl/Tz7GT5/6NmwiWtqbxqVafJOwoqIY1FQFNtPgDobDQrPgkCSFta R2JCeGTbrkk756pl/kZTDf7d7bw+Cnv1Rt0CzCdcvxk+piYM/yxYeYJvL/l7Tm5wjIQmH rd5PtznA/nA8ACbb+hpRdQjaerw/pWHxgebolYX2VlIitaXBYFP/0rNTR51aJ6Ou+MyDE dBNpmOdeHb1QG/O/iMfR1TLqtTkxvYIh0a2m4aQNDlKv8UUdVCLIdA7RtTuBATNyJag== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=dfYVxPB9; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3E071606B147; Mon, 2 Nov 2026 12:02:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=dfYVxPB9 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1CC701F00A1A; Mon, 2 Nov 2026 12:02:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793620953; bh=Fr0PNZ8uIjWuUyi5jHRttjfJcgJHs22wa+3cbgmTv6Y=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=dfYVxPB9FUjwqMKzUEdki3dEUE+JjX6MW5u4ot6oLabApyiP1RviAtUeLvEP5pm6u MPMpM/JZfubJfG5nvMPUo7oxtSxvXnyaBxH1JAytGEU1MzHjhlDT5sqXiX5qKA2F4/ K5KtA2DnKWSFNcCl3ALFAhmhU+4MPPUjHzB2A26ihsykZGkHGq2jtzUJvdL9umrjta 70PMnZM8vC8QoDil13KxnBIessCPw+qVfUOjd4fbnS8z8Yaf8C+SeICJBEzBjn9E62 2gSOri5oI1X4LuRN6e8u5anUFi1gE0+Vgxbg9zdBNBq2qn7dhQh8r7ybGoLO/WM4qG 6w4znKQSvSrHQ== Date: Mon, 2 Nov 2026 12:02:30 +0000 From: Simon Horman To: Linkui Xiao Cc: jiri@resnulli.us, davem@davemloft.net, edumazet@kernel.org, kuba@kernel.org, pabeni@redhat.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Linkui Xiao Subject: Re: [PATCH net 2/2] devlink: sb: do not dereference a missing shared buffer Message-ID: <20261102120230.GC257209@horms.kernel.org> References: <20261030033332.3685172-1-xiaolinkui@126.com> <20261030033332.3685172-3-xiaolinkui@126.com> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261030033332.3685172-3-xiaolinkui@126.com> On Fri, Oct 30, 2026 at 11:33:32AM +0800, Linkui Xiao wrote: > From: Linkui Xiao > > devl_sb_unregister() looks the shared buffer up by index and only warns > when it is not on the list. list_del() and kfree() are then called on the > NULL result, so unregistering an index that was never registered, or > unregistering the same index twice, turns the warning into a NULL pointer > dereference. list is the first member of struct devlink_sb, so list_del() > reads the next and prev pointers from address 0 before storing to them. > > The register side already fails gracefully: devl_sb_register() returns > -EEXIST when the index is taken. Make the unregister side symmetric and > return after the warning. > > Fixes: bf7974710a40 ("devlink: add shared buffer configuration") > Signed-off-by: Linkui Xiao Reviewed-by: Simon Horman