From: Breno Leitao <leitao@debian.org>
To: Ali Tariq <alitariq45892@gmail.com>
Cc: netdev@vger.kernel.org, Andrew Lunn <andrew+netdev@lunn.ch>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@kernel.org>,
Jakub Kicinski <kuba@kernel.org>,
Paolo Abeni <pabeni@redhat.com>, Yixun Lan <dlan@kernel.org>,
Troy Mitchell <troy.mitchell@linux.spacemit.com>,
Vivian Wang <wangruikang@iscas.ac.cn>,
Chukun Pan <amadeus@jmu.edu.cn>,
Siddharth Vadapalli <s-vadapalli@ti.com>,
Tomas Hlavacek <tmshlvck@gmail.com>,
Muhammad Bilal <meatuni001@gmail.com>,
Vadim Fedorenko <vadim.fedorenko@linux.dev>,
Maxime Chevallier <maxime.chevallier@bootlin.com>,
"open list:RISC-V SPACEMIT SoC Support"
<linux-riscv@lists.infradead.org>,
"open list:RISC-V SPACEMIT SoC Support"
<spacemit@lists.linux.dev>,
open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH net] net: spacemit: Hold RTNL lock in emac_resume() and emac_suspend()
Date: Thu, 5 Nov 2026 05:40:31 -0800 [thread overview]
Message-ID: <auyG7hGJtMzV0Gbi@gmail.com> (raw)
In-Reply-To: <20261105123441.2524171-1-alitariq45892@gmail.com>
On Thu, Nov 05, 2026 at 05:34:37PM +0500, Ali Tariq wrote:
> The emac_resume() calls the emac_open() and emac_suspend() calls
> emac_stop() functions directly without holding the lock through
> rtnl_lock(). These functions rely on phy_disconnect() which reads pointer
> with rtnl_dereference(). But since no lock is being held,
> rtnl_dereference throws a suspicious RCU usage on
> Orange Pi RV2 (SpacemiT K1) warning when lockdep is enabled.
>
> WARNING: suspicious RCU usage
> drivers/net/phy/phy_device.c:1831 suspicious rcu_dereference_protected() usage!
> Call Trace:
> phy_detach_internal+0x490/0x5f2
> phy_disconnect+0x90/0xc0
> emac_stop+0x114/0x626
> emac_suspend+0xac/0x126
> platform_pm_suspend+0x72/0xe4
>
> Hold RTNL lock before emac_open() and emac_stop() with rtnl_lock() and
> release the lock when functions return with rtnl_unlock().
This would work, but I am wondering if it would be possible to call rtnl
inside the _open function, when dealing with the PHY? in other words,
shrink the time rtnl is held.
next prev parent reply other threads:[~2026-11-05 13:40 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-11-05 12:34 Ali Tariq
2026-11-05 13:40 ` Breno Leitao [this message]
2026-11-05 22:28 ` Vadim Fedorenko
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