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From: Simon Horman <horms@kernel.org>
To: Jijie Shao <shaojijie@huawei.com>
Cc: davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
	pabeni@redhat.com, andrew+netdev@lunn.ch, shenjian15@huawei.com,
	liuyonglong@huawei.com, chenhao418@huawei.com,
	jonathan.cameron@huawei.com,
	shameerali.kolothum.thodi@huawei.com, salil.mehta@huawei.com,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH net 2/3] net: hibmcge: fix the division by zero issue
Date: Fri, 1 Aug 2025 11:11:54 +0100	[thread overview]
Message-ID: <20250801101154.GK8494@horms.kernel.org> (raw)
In-Reply-To: <20250731134749.4090041-3-shaojijie@huawei.com>

On Thu, Jul 31, 2025 at 09:47:48PM +0800, Jijie Shao wrote:
> When the network port is down, the queue is released, and ring->len is 0.
> In debugfs, hbg_get_queue_used_num() will be called,
> which may lead to a division by zero issue.
> 
> This patch adds a check, if ring->len is 0,
> hbg_get_queue_used_num() directly returns 0.
> 
> Fixes: 40735e7543f9 ("net: hibmcge: Implement .ndo_start_xmit function")
> Signed-off-by: Jijie Shao <shaojijie@huawei.com>

Thanks,

Thinking aloud:

I see that hbg_get_queue_used_num() can be called for both RX and TX
rings via the debugfs code hbg_dbg_ring(). And that hbg_net_stop()
clears the RX and TX ring configuration using hbg_txrx_uninit().

So I agree that when the port is down ring-len will be 0.

Reviewed-by: Simon Horman <horms@kernel.org>

  reply	other threads:[~2025-08-01 10:11 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-07-31 13:47 [PATCH net 0/3] There are some bugfix for hibmcge ethernet driver Jijie Shao
2025-07-31 13:47 ` [PATCH net 1/3] net: hibmcge: fix rtnl deadlock issue Jijie Shao
2025-08-01 10:05   ` Simon Horman
2025-08-01 10:44     ` Jijie Shao
2025-08-01 11:05       ` Simon Horman
2025-07-31 13:47 ` [PATCH net 2/3] net: hibmcge: fix the division by zero issue Jijie Shao
2025-08-01 10:11   ` Simon Horman [this message]
2025-08-01 10:46     ` Jijie Shao
2025-07-31 13:47 ` [PATCH net 3/3] net: hibmcge: fix the np_link_fai error reporting issue Jijie Shao
2025-08-01 10:20   ` Simon Horman

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