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] Reviewed-by: Jason Gunthorpe <[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 d48d3b2abd68..0523555933c9 100644 --- a/mm/mmu_notifier.c +++ b/mm/mmu_notifier.c @@ -259,6 +259,13 @@ int __mmu_notifier_register(struct mmu_notifier *mn, struct mm_struct *mm) lockdep_assert_held_write(&mm->mmap_sem); 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); + } + mn->mm = mm; mn->users = 1; -- 2.23.0 _______________________________________________ dri-devel mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/dri-devel
