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 587EC17B50A; Tue, 7 Jan 2025 16:36:11 +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=1736267771; cv=none; b=O/Ddye2F3nd2G15Qghqgla+sQAI/GgJdWu0K7W928cZOKQGVzfycFBOIfdHWkaWwHQvV+0LFDy+vu13IPFxudXM1dSXIs4hUHOM+xaA+p0PKE0pX2AFvu8UIiV1dyt+JMkcCyqLOyKt+L1ylaIGaLXSvL01CrLY/q00POk47pOM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736267771; c=relaxed/simple; bh=vzUy837LTyBXWf89XS3TbwkCCyKms+5Y1Lql1pXQSKg=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=a0DzPBMt6037FZSPdlMz4q3Uo1etyoCnKSHP+fEzH2m8fTKe6ah5+78WDS8M0S4uTpfd6illODp6HhtuOwIhDMFSSm0qQBsM+OrDoiw/22q9wYxAL//Pdwy9IIVQPHaiEA6B/Yh5Qe7BLLFq4ASLqVmDdvHYZqRMml8DEjtAUKM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=pEMTeyK+; 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="pEMTeyK+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 83A43C4CED6; Tue, 7 Jan 2025 16:36:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1736267770; bh=vzUy837LTyBXWf89XS3TbwkCCyKms+5Y1Lql1pXQSKg=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=pEMTeyK+4/4l4RjvrmYXzKeX2NGzmnOhakTbV6zBZK4zIn1RJqtQHYYoLuJ4lFhHO FO5REhS48U4ekxqsjsHMH7MUVm8PSFLjg5JRolhaQczXwf8MV7YGBEk+YYe4FzoNJV N9o7e+a9YFCSPtMoCKQJpBBqph5zQNCwN07R2Xw6T7jIBU85GhEg6BxY+U4ePdRBzV PJv1ev1Gv2OJOOFCRsdGb6fb+mCS81A+lEMX6GYqDVHKzsZ8hT7HGDujzxH3eOS2vw zwG4TlVunT9Tl26UEBTSLX80JNpa0W5PyzfLuw0HhlHvts5LAWIU6tmRKPiG2FZdt5 cW7MtWcc5NCoA== Date: Tue, 7 Jan 2025 08:36:09 -0800 From: Jakub Kicinski To: Willem de Bruijn Cc: davem@davemloft.net, netdev@vger.kernel.org, edumazet@google.com, pabeni@redhat.com, stable@vger.kernel.org, jdamato@fastly.com, almasrymina@google.com, amritha.nambiar@intel.com, sridhar.samudrala@intel.com Subject: Re: [PATCH net] netdev: prevent accessing NAPI instances from another namespace Message-ID: <20250107083609.55ddf0d6@kernel.org> In-Reply-To: <677d27cc5d9b_25382b294fd@willemb.c.googlers.com.notmuch> References: <20250106180137.1861472-1-kuba@kernel.org> <677d27cc5d9b_25382b294fd@willemb.c.googlers.com.notmuch> 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 Tue, 07 Jan 2025 08:10:36 -0500 Willem de Bruijn wrote: > > +/* must be called under rcu_read_lock(), as we dont take a reference */ > > Instead of function comments, invariant checks in code? > > Like in dev_get_by_napi_id: > > WARN_ON_ONCE(!rcu_read_lock_held()); Can I do it as a follow up? Adding the warning to napi_by_id() reveals that napi_hash_add() currently walks the list without holding the RCU lock :)