linux-kernel - Re: [PATCH] hns3: work around stack size warning

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: <13cf4327-f04f-455e-9a3a-1c74b22f42d0@app.fastmail.com>
Date: Mon, 23 Jun 2025 07:56:06 +0200
From: "Arnd Bergmann" <arnd@...db.de>
To: "Jijie Shao" <shaojijie@...wei.com>, "Jakub Kicinski" <kuba@...nel.org>
Cc: "Jian Shen" <shenjian15@...wei.com>,
 "Salil Mehta" <salil.mehta@...wei.com>,
 "Andrew Lunn" <andrew+netdev@...n.ch>,
 "David S . Miller" <davem@...emloft.net>,
 "Eric Dumazet" <edumazet@...gle.com>, "Paolo Abeni" <pabeni@...hat.com>,
 "Nathan Chancellor" <nathan@...nel.org>,
 "Nick Desaulniers" <nick.desaulniers+lkml@...il.com>,
 "Bill Wendling" <morbo@...gle.com>, "Justin Stitt" <justinstitt@...gle.com>,
 "Hao Lan" <lanhao@...wei.com>, "Guangwei Zhang" <zhangwangwei6@...wei.com>,
 Netdev <netdev@...r.kernel.org>, linux-kernel@...r.kernel.org,
 llvm@...ts.linux.dev
Subject: Re: [PATCH] hns3: work around stack size warning

On Mon, Jun 23, 2025, at 05:19, Jijie Shao wrote:
>> on 2025/6/12 23:33, Jakub Kicinski wrote:
>>
>
> *Hi Jakub, Arnd We have changed the impleament as your suggestion. Would 
> you please help check it ? If it's OK, we will rewrite the rest parts of 
> our debugfs code. Thanks! *

The conversion to seq_file looks good to me, this does address the
stack usage problems I was observing.
Thanks for cleaning this up!

> -    sprintf(result[j++], "%u", index);
> -    sprintf(result[j++], "%u", readl_relaxed(ring->tqp->io_base +
> -        HNS3_RING_TX_RING_BD_NUM_REG));
> +    seq_printf(s, "%-4u%6s", index, " ");
> +    seq_printf(s, "%-5u%3s",
> +           readl_relaxed(base + HNS3_RING_TX_RING_BD_NUM_REG), " ");

I'm not sure I understand the format string changes here, I did
not think they were necessary.

Are you doing this to keep the output the same as before, or are
you reformatting the contents for readability?

> +static int hns3_dbg_common_init_t1(struct hnae3_handle *handle, u32 
> cmd)
> +{
> +    struct device *dev = &handle->pdev->dev;
> +    struct dentry *entry_dir;
> +    read_func func = NULL;
> +
> +    switch (hns3_dbg_cmd[cmd].cmd) {
> +    case HNAE3_DBG_CMD_TX_QUEUE_INFO:
> +        func = hns3_dbg_tx_queue_info;
> +        break;
> +    default:
> +        return -EINVAL;
> +    }
> +
> +    entry_dir = hns3_dbg_dentry[hns3_dbg_cmd[cmd].dentry].dentry;
> +    debugfs_create_devm_seqfile(dev, hns3_dbg_cmd[cmd].name, entry_dir,
> +                    func);
> +
> +    return 0;

This will work fine as well, but I think you can do slightly better
by having your own file_operations with a read function based
on single_open() and your current hns3_dbg_read_cmd().

I don't think you gain anything from using debugfs_create_devm_seqfile()
since you use debugfs_remove_recursive() for cleaning it up anyway.

     Arnd