We want to teach lockdep that mmu notifiers can be called from direct reclaim paths, since on many CI systems load might never reach that level (e.g. when just running fuzzer or small functional tests).
Motivated by a discussion with Jason. I've put the annotation into mmu_notifier_register since only when we have mmu notifiers registered is there any point in teaching lockdep about them. Also, we already have a kmalloc(, GFP_KERNEL), so this is safe. Cc: Jason Gunthorpe <[email protected]> Cc: Chris Wilson <[email protected]> Cc: Andrew Morton <[email protected]> Cc: David Rientjes <[email protected]> Cc: "Jérôme Glisse" <[email protected]> Cc: Michal Hocko <[email protected]> Cc: "Christian König" <[email protected]> Cc: Greg Kroah-Hartman <[email protected]> Cc: Daniel Vetter <[email protected]> Cc: Mike Rapoport <[email protected]> Cc: [email protected] Signed-off-by: Daniel Vetter <[email protected]> --- mm/mmu_notifier.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/mm/mmu_notifier.c b/mm/mmu_notifier.c index d12e3079e7a4..538d3bb87f9b 100644 --- a/mm/mmu_notifier.c +++ b/mm/mmu_notifier.c @@ -256,6 +256,13 @@ static int do_mmu_notifier_register(struct mmu_notifier *mn, BUG_ON(atomic_read(&mm->mm_users) <= 0); + if (IS_ENABLED(CONFIG_LOCKDEP)) { + fs_reclaim_acquire(GFP_KERNEL); + lock_map_acquire(&__mmu_notifier_invalidate_range_start_map); + lock_map_release(&__mmu_notifier_invalidate_range_start_map); + fs_reclaim_release(GFP_KERNEL); + } + ret = -ENOMEM; mmu_notifier_mm = kmalloc(sizeof(struct mmu_notifier_mm), GFP_KERNEL); if (unlikely(!mmu_notifier_mm)) -- 2.23.0.rc1 _______________________________________________ dri-devel mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/dri-devel
