Re: WARNING: CPU: 1 PID: 1 at net/core/netpoll.c:370 netpoll_send_skb+0x1fc/0x20c at boot when netconsole is enabled (kernel v6.9-rc5, v6.8.7, sungem, PowerMac G4 DP)

From: Jakub Kicinski
Date: Mon May 06 2024 - 10:27:02 EST

Next message: Louis Chauvet: "[PATCH v2] spi: omap2-mcspi: Ensure that CS is correctly asserted when switching from MULTI mode to SINGLE mode"
Previous message: Andy Shevchenko: "Re: [PATCH v1 1/1] ALSA: Correct the kernel object suffix of target"
In reply to: Erhard Furtner: "Re: WARNING: CPU: 1 PID: 1 at net/core/netpoll.c:370 netpoll_send_skb+0x1fc/0x20c at boot when netconsole is enabled (kernel v6.9-rc5, v6.8.7, sungem, PowerMac G4 DP)"
Next in thread: Erhard Furtner: "Re: WARNING: CPU: 1 PID: 1 at net/core/netpoll.c:370 netpoll_send_skb+0x1fc/0x20c at boot when netconsole is enabled (kernel v6.9-rc5, v6.8.7, sungem, PowerMac G4 DP)"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]

On Sun, 5 May 2024 23:27:13 +0200 Erhard Furtner wrote:
> > On Sun, 28 Apr 2024 12:53:06 +0200 Erhard Furtner wrote:
> > > With netconsole enabled I get this "WARNING: CPU: 1 PID: 1 at
> > > net/core/netpoll.c:370 netpoll_send_skb+0x1fc/0x20c" and "WARNING:
> > > CPU: 1 PID: 1 at kernel/locking/irqflag-debug.c:10
> > > warn_bogus_irq_restore+0x30/0x44" at boot on my PowerMac G4 DP.
> > > Happens more often than not (6-7 out of 10 times booting):
> >
> > Could you try with LOCKDEP enabled?
> > I wonder if irqs_disabled() behaves differently than we expect.
>
> Ok, after a few tries I got a "BUG: spinlock wrong CPU on CPU#0, swapper/0/1" LOCKDEP hit. But this does not happen every time when I get the netpoll_send WARNING:

Oh, can you try deleting the gem_poll_controller() function?
Unhook it from ndo_poll_controller and remove it completely.