Hello Jamie, On Mon, 2010-06-14 at 16:04 +0100, Jamie Lokier wrote: > Philby John wrote: > > mtd: Fix bug using smp_processor_id() in preemptible ubi_bgt1d kthread > > > > On a MIPS Cavium Octeon CN5020 when trying to create a UBI volume, > > on the NOR flash, the kernel thread ubi_bgt1d calls > > cfi_amdstd_write_buffers() --> do_write_buffer() --> > > INVALIDATE_CACHE_UDELAY --> __udelay(). Its __udelay() that calls > > smp_processor_id() in preemptible code, which you are not supposed to. > > Fix the problem by disabling preemption. > > The MTD code just calls udelay(). > Are you sure it isn't permitted to call udelay() from preemptible code? > I think it is fine. > > Perhaps MIPS udelay() should be disabling preemption itself, or > (as x86 does) using raw_smp_processor_id() instead? Sorry for the noise. I now find that raw_smp_processor_id() has been implemented specific to MIPS in the latest kernel, I was using 2.6.32. Thanks and regards, Philby
