This is an attempt to fix a few different related issues around switching mm, TLB flushing, and lazy tlb mm handling.
This will require all architectures to eventually move to disabling irqs over activate_mm, but it's possible we could add another arch call after irqs are re-enabled for those few which can't do their entire activation with irqs disabled. Testing so far indicates this has fixed a mm refcounting bug that powerpc was running into (via distro report and backport). I haven't had any real feedback on this series outside powerpc (and it doesn't really affect other archs), so I propose patches 1,2,4 go via the powerpc tree. There is no dependency between them and patch 3, I put it there only because it follows the history of the code (powerpc code was written using the sparc64 logic), but I guess they have to go via different arch trees. Dave, I'll leave patch 3 with you. Thanks, Nick Since v1: - Updates from Michael Ellerman's review comments. Nicholas Piggin (4): mm: fix exec activate_mm vs TLB shootdown and lazy tlb switching race powerpc: select ARCH_WANT_IRQS_OFF_ACTIVATE_MM sparc64: remove mm_cpumask clearing to fix kthread_use_mm race powerpc/64s/radix: Fix mm_cpumask trimming race vs kthread_use_mm arch/Kconfig | 7 +++ arch/powerpc/Kconfig | 1 + arch/powerpc/include/asm/mmu_context.h | 2 +- arch/powerpc/include/asm/tlb.h | 13 ------ arch/powerpc/mm/book3s64/radix_tlb.c | 23 ++++++--- arch/sparc/kernel/smp_64.c | 65 ++++++-------------------- fs/exec.c | 17 ++++++- 7 files changed, 54 insertions(+), 74 deletions(-) -- 2.23.0
