From: Mike Galbraith <efault@gmx.de>
To: lkml <linux-kernel@vger.kernel.org>
Cc: Robert Hancock <robert.hancock@calian.com>,
Doug Berger <opendmb@gmail.com>,
Florian Fainelli <florian.fainelli@broadcom.com>,
Breno Leitao <leitao@debian.org>
Subject: netpoll: raspberrypi [4 5] driver locking woes
Date: Mon, 25 Aug 2025 07:53:42 +0200 [thread overview]
Message-ID: <4698029bbe7d7a33edd905a027e3a183ac51ad8a.camel@gmx.de> (raw)
Greetings,
After meeting some netconsole+ieee80211 woes recently, I decided to
build a lockdep enabled 6.17-rc2 kernel for my rpi[45] and give it a go
on their wired nics just to make sure there were no surprises lurking..
but damn the bad luck, both cute/dinky boxen whimpered.
The pi5 met locking woes due to...
138badbc21a0 net: macb: use NAPI for TX completion path
...injecting spin_lock/unlock_irq() into polling, which inspired
netpoll.c to point a finger directly at the driver. A quick poke
didn't produce instant gratification, but a wedged in revert did.
On the pi4, lockdep muttered about ring->lock in bcmgenet_xmit() and
bcmgenet_tx_poll() - switching to irqsave/restore spinlock variants
there silenced it.
Note to readers: before turning on lockdep, perhaps consider whacking
lockdep_assert_held() instances in gpiolib.c.. ymmv, but here it would
have saved time and naughty language expenditure.
-Mike
next reply other threads:[~2025-08-25 5:53 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-08-25 5:53 Mike Galbraith [this message]
2025-08-25 10:10 ` Mike Galbraith
2025-08-26 9:49 ` Mike Galbraith
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