linux-kernel - Re: [PATCH] nvme-fabrics: use reserved tag for reg read/write command

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]

Date: Tue, 30 Apr 2024 03:46:59 +0000
From: Chaitanya Kulkarni <chaitanyak@...dia.com>
To: brookxu.cn <brookxu.cn@...il.com>
CC: "linux-nvme@...ts.infradead.org" <linux-nvme@...ts.infradead.org>,
	"hch@....de" <hch@....de>, "kbusch@...nel.org" <kbusch@...nel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"axboe@...nel.dk" <axboe@...nel.dk>, "sagi@...mberg.me" <sagi@...mberg.me>
Subject: Re: [PATCH] nvme-fabrics: use reserved tag for reg read/write command

On 4/29/2024 7:17 PM, brookxu.cn wrote:
> From: Chunguang Xu <chunguang.xu@...pee.com>
> 
> In some scenarios, if too many commands are issued by nvme command in
> the same time by user tasks, this may exhaust all tags of admin_q. If
> a reset (nvme reset or IO timeout) occurs before these commands finish,
> reconnect routine may fail to update nvme regs due to insufficient tags,
> which will cause kernel hang forever. In order to workaround this issue,
> maybe we can let reg_read32()/reg_read64()/reg_write32() use reserved
> tags. This maybe safe for nvmf:
> 
> 1. For the disable ctrl path,  we will not issue connect command
> 2. For the enable ctrl / fw activate path, since connect and reg_xx()
>     are called serially.
> 

Given the complexity of the scenario described above, is it possible to 
write a script for this scenario that will trigger this and submit to 
blktest ? not that this is a blocker to get this patch reviewed, but 
believe it is needed in long run, WDYT ?

> So the reserved tags may still be enough while reg_xx() use reserved tags.
> 
> Signed-off-by: Chunguang Xu <chunguang.xu@...pee.com>
> ---

-ck