From: Suren Baghdasaryan Date: Thu, 13 Feb 2025 22:46:40 +0000 (-0800) Subject: mm: mark vma as detached until it's added into vma tree X-Git-Tag: v6.15-rc1~81^2~325 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=8ef95d8f15f9e785341775814f0ed2ee22017aa5;p=thirdparty%2Flinux.git mm: mark vma as detached until it's added into vma tree Current implementation does not set detached flag when a VMA is first allocated. This does not represent the real state of the VMA, which is detached until it is added into mm's VMA tree. Fix this by marking new VMAs as detached and resetting detached flag only after VMA is added into a tree. Introduce vma_mark_attached() to make the API more readable and to simplify possible future cleanup when vma->vm_mm might be used to indicate detached vma and vma_mark_attached() will need an additional mm parameter. Link: https://lkml.kernel.org/r/20250213224655.1680278-4-surenb@google.com Signed-off-by: Suren Baghdasaryan Reviewed-by: Shakeel Butt Reviewed-by: Lorenzo Stoakes Reviewed-by: Vlastimil Babka Reviewed-by: Liam R. Howlett Tested-by: Shivank Garg Link: https://lkml.kernel.org/r/5e19ec93-8307-47c2-bb13-3ddf7150624e@amd.com Cc: Christian Brauner Cc: David Hildenbrand Cc: David Howells Cc: Davidlohr Bueso Cc: Hugh Dickins Cc: Jann Horn Cc: Johannes Weiner Cc: Jonathan Corbet Cc: Klara Modin Cc: Lokesh Gidra Cc: Mateusz Guzik Cc: Matthew Wilcox Cc: Mel Gorman Cc: Michal Hocko Cc: Minchan Kim Cc: Oleg Nesterov Cc: Pasha Tatashin Cc: "Paul E . McKenney" Cc: Peter Xu Cc: Peter Zijlstra (Intel) Cc: Sourav Panda Cc: Wei Yang Cc: Will Deacon Cc: Heiko Carstens Cc: Stephen Rothwell Signed-off-by: Andrew Morton --- diff --git a/include/linux/mm.h b/include/linux/mm.h index bf3b6362927f2..d333d4070362c 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -821,12 +821,21 @@ static inline void vma_assert_locked(struct vm_area_struct *vma) vma_assert_write_locked(vma); } -static inline void vma_mark_detached(struct vm_area_struct *vma, bool detached) +static inline void vma_mark_attached(struct vm_area_struct *vma) +{ + vma->detached = false; +} + +static inline void vma_mark_detached(struct vm_area_struct *vma) { /* When detaching vma should be write-locked */ - if (detached) - vma_assert_write_locked(vma); - vma->detached = detached; + vma_assert_write_locked(vma); + vma->detached = true; +} + +static inline bool is_vma_detached(struct vm_area_struct *vma) +{ + return vma->detached; } static inline void release_fault_lock(struct vm_fault *vmf) @@ -857,8 +866,8 @@ static inline void vma_end_read(struct vm_area_struct *vma) {} static inline void vma_start_write(struct vm_area_struct *vma) {} static inline void vma_assert_write_locked(struct vm_area_struct *vma) { mmap_assert_write_locked(vma->vm_mm); } -static inline void vma_mark_detached(struct vm_area_struct *vma, - bool detached) {} +static inline void vma_mark_attached(struct vm_area_struct *vma) {} +static inline void vma_mark_detached(struct vm_area_struct *vma) {} static inline struct vm_area_struct *lock_vma_under_rcu(struct mm_struct *mm, unsigned long address) @@ -891,7 +900,10 @@ static inline void vma_init(struct vm_area_struct *vma, struct mm_struct *mm) vma->vm_mm = mm; vma->vm_ops = &vma_dummy_vm_ops; INIT_LIST_HEAD(&vma->anon_vma_chain); - vma_mark_detached(vma, false); +#ifdef CONFIG_PER_VMA_LOCK + /* vma is not locked, can't use vma_mark_detached() */ + vma->detached = true; +#endif vma_numab_state_init(vma); vma_lock_init(vma); } @@ -1086,6 +1098,7 @@ static inline int vma_iter_bulk_store(struct vma_iterator *vmi, if (unlikely(mas_is_err(&vmi->mas))) return -ENOMEM; + vma_mark_attached(vma); return 0; } diff --git a/kernel/fork.c b/kernel/fork.c index bdbabe73fb294..5bf3e407c795b 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -465,6 +465,10 @@ struct vm_area_struct *vm_area_dup(struct vm_area_struct *orig) data_race(memcpy(new, orig, sizeof(*new))); vma_lock_init(new); INIT_LIST_HEAD(&new->anon_vma_chain); +#ifdef CONFIG_PER_VMA_LOCK + /* vma is not locked, can't use vma_mark_detached() */ + new->detached = true; +#endif vma_numab_state_init(new); dup_anon_vma_name(orig, new); diff --git a/mm/memory.c b/mm/memory.c index 94feb51a79832..6ef014220e09c 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -6374,7 +6374,7 @@ retry: goto inval; /* Check if the VMA got isolated after we found it */ - if (vma->detached) { + if (is_vma_detached(vma)) { vma_end_read(vma); count_vm_vma_lock_event(VMA_LOCK_MISS); /* The area was replaced with another one */ diff --git a/mm/vma.c b/mm/vma.c index 603e538a093ff..702e2181f8b7f 100644 --- a/mm/vma.c +++ b/mm/vma.c @@ -341,7 +341,7 @@ static void vma_complete(struct vma_prepare *vp, struct vma_iterator *vmi, if (vp->remove) { again: - vma_mark_detached(vp->remove, true); + vma_mark_detached(vp->remove); if (vp->file) { uprobe_munmap(vp->remove, vp->remove->vm_start, vp->remove->vm_end); @@ -1238,7 +1238,7 @@ static void reattach_vmas(struct ma_state *mas_detach) mas_set(mas_detach, 0); mas_for_each(mas_detach, vma, ULONG_MAX) - vma_mark_detached(vma, false); + vma_mark_attached(vma); __mt_destroy(mas_detach->tree); } @@ -1313,7 +1313,7 @@ static int vms_gather_munmap_vmas(struct vma_munmap_struct *vms, if (error) goto munmap_gather_failed; - vma_mark_detached(next, true); + vma_mark_detached(next); nrpages = vma_pages(next); vms->nr_pages += nrpages; diff --git a/mm/vma.h b/mm/vma.h index e55e68abfbe3a..bffb56afce5f4 100644 --- a/mm/vma.h +++ b/mm/vma.h @@ -205,6 +205,7 @@ static inline int vma_iter_store_gfp(struct vma_iterator *vmi, if (unlikely(mas_is_err(&vmi->mas))) return -ENOMEM; + vma_mark_attached(vma); return 0; } @@ -437,6 +438,7 @@ static inline void vma_iter_store(struct vma_iterator *vmi, __mas_set_range(&vmi->mas, vma->vm_start, vma->vm_end - 1); mas_store_prealloc(&vmi->mas, vma); + vma_mark_attached(vma); } static inline unsigned long vma_iter_addr(struct vma_iterator *vmi) diff --git a/tools/testing/vma/vma_internal.h b/tools/testing/vma/vma_internal.h index 4506e6fb3c6fa..f93f7f74f97b2 100644 --- a/tools/testing/vma/vma_internal.h +++ b/tools/testing/vma/vma_internal.h @@ -471,12 +471,16 @@ static inline void vma_lock_init(struct vm_area_struct *vma) } static inline void vma_assert_write_locked(struct vm_area_struct *); -static inline void vma_mark_detached(struct vm_area_struct *vma, bool detached) +static inline void vma_mark_attached(struct vm_area_struct *vma) +{ + vma->detached = false; +} + +static inline void vma_mark_detached(struct vm_area_struct *vma) { /* When detaching vma should be write-locked */ - if (detached) - vma_assert_write_locked(vma); - vma->detached = detached; + vma_assert_write_locked(vma); + vma->detached = true; } extern const struct vm_operations_struct vma_dummy_vm_ops; @@ -489,7 +493,8 @@ static inline void vma_init(struct vm_area_struct *vma, struct mm_struct *mm) vma->vm_mm = mm; vma->vm_ops = &vma_dummy_vm_ops; INIT_LIST_HEAD(&vma->anon_vma_chain); - vma_mark_detached(vma, false); + /* vma is not locked, can't use vma_mark_detached() */ + vma->detached = true; vma_lock_init(vma); } @@ -515,6 +520,8 @@ static inline struct vm_area_struct *vm_area_dup(struct vm_area_struct *orig) memcpy(new, orig, sizeof(*new)); vma_lock_init(new); INIT_LIST_HEAD(&new->anon_vma_chain); + /* vma is not locked, can't use vma_mark_detached() */ + new->detached = true; return new; }