linux-kernel - Re: [PATCH v1 1/3] net: hisilicon: make hip04_tx

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20190805174618.2b3b551a@cakuba.netronome.com>
Date:   Mon, 5 Aug 2019 17:46:18 -0700
From:   Jakub Kicinski <jakub.kicinski@...ronome.com>
To:     Jiangfeng Xiao <xiaojiangfeng@...wei.com>
Cc:     <davem@...emloft.net>, <yisen.zhuang@...wei.com>,
        <salil.mehta@...wei.com>, <netdev@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <leeyou.li@...wei.com>,
        <xiaowei774@...wei.com>, <nixiaoming@...wei.com>
Subject: Re: [PATCH v1 1/3] net: hisilicon: make hip04_tx_reclaim
 non-reentrant

On Sat, 3 Aug 2019 20:31:39 +0800, Jiangfeng Xiao wrote:
> If hip04_tx_reclaim is interrupted while it is running
> and then __napi_schedule continues to execute
> hip04_rx_poll->hip04_tx_reclaim, reentrancy occurs
> and oops is generated. So you need to mask the interrupt
> during the hip04_tx_reclaim run.

Napi poll method for the same napi instance can't be run concurrently.
Could you explain a little more what happens here?

Also looking at hip04_rx_poll() I don't think the interrupt re-enabling
logic guarantees the interrupt is not armed when NAPI is scheduled.
Please note that NAPI is no longer scheduled if napi_complete_done()
returned false.