[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Old Index]
Re: MPSAFE and KERNEL_LOCK
On Fri, May 11, 2018 at 6:41 PM Ryota Ozaki <ozaki-r%netbsd.org@localhost> wrote:
> On Fri, May 11, 2018 at 3:53 PM Michael van Elst <mlelstv%serpens.de@localhost>
> > A traditional ethernet driver receives input via an interrupt routine
> > and passes packets to ether_input(). The data is protected by disabling
> > the receive interrupt.
> > In multiprocessor land, the same is achieved by also acquiring the
> > big kernel lock.
> > Current code however queues incoming packets in a percpuq and passes
> > things through a softint tagged as MPSAFE. The softint handler is
> > ether_input without holding the kernel lock.
> > There is another unprotected path in bpf_write calling into the
> > _if_input vector directly without locking (bpf device is tagged MPSAFE)
> > and without disabling interrupts.
> > Did I miss something?
> You're right.
> Not holding KERNEL_LOCK in ether_input can be problematic if we use
> CARP and/or AGR (and NETATALK) that are not MP-safe. Also calling
> _if_ipnput without splsoftnet from bpf_write is problematic as you said.
> The following patch should fix the issue:
I committed the patch with the same fix for ether_input from bridge_output.
Main Index |
Thread Index |