Re: [PATCH net] net: sysfs: Fix deadlock situation in sysfs accesses

[Christophe Leroy]

Le 17/12/2024 à 16:30, Andrew Lunn a écrit :
> On Tue, Dec 17, 2024 at 08:18:25AM +0100, Christophe Leroy wrote:
> > The following problem is encountered on kernel built with
> > CONFIG_PREEMPT. An snmp daemon running with normal priority is
> > regularly calling ioctl(SIOCGMIIPHY).
>
> Why is an SNMP daemon using that IOCTL? What MAC driver is this? Is it
> using phylib? For phylib, that IOCTL is supposed to be for debug only,
> and is a bit of a foot gun. So i would not recommend it.

That's the well-known Net-SNMP package.

See for instance 
https://github.com/net-snmp/net-snmp/blob/master/agent/mibgroup/if-mib/data_access/interface_linux.c#L954

The MAC is ucc_geth driver, it is phylib for the moment, it is being 
converted to phylink in net-next , see commit 53036aa8d031 ("net: 
freescale: ucc_geth: phylink conversion")

Christophe