On Sun, Aug 09, 2020 at 08:42:51PM +0200, Ahmed S. Darwish wrote: > On Sat, Aug 08, 2020 at 04:21:22PM -0700, Guenter Roeck wrote: > > On Mon, Jul 20, 2020 at 05:55:14PM +0200, Ahmed S. Darwish wrote: > > > Preemption must be disabled before entering a sequence count write side > > > critical section. Failing to do so, the seqcount read side can preempt > > > the write side section and spin for the entire scheduler tick. If that > > > reader belongs to a real-time scheduling class, it can spin forever and > > > the kernel will livelock. > > > > > > Assert through lockdep that preemption is disabled for seqcount writers. > > > > > > > This patch is causing compile failures for various images (eg > > arm:allmodconfig, > > arm:imx_v6_v7_defconfig, mips:allmodconfig). > > > > In file included from arch/arm/include/asm/bug.h:60, > > from include/linux/bug.h:5, > > from include/linux/thread_info.h:12, > > from include/asm-generic/current.h:5, > > from ./arch/arm/include/generated/asm/current.h:1, > > from include/linux/sched.h:12, > > from arch/arm/kernel/asm-offsets.c:11: > > include/linux/seqlock.h: In function 'write_seqcount_begin_nested': > > include/asm-generic/percpu.h:31:40: error: implicit declaration of function > > 'raw_smp_processor_id' > > > > Reverting it fixes the problem. Is this being addressed ? > > > > @Peter, I think let's revert this one for now?
Please do, it's blowing up my local builds as well :( thanks, greg k-h
