From 55e50223bf3e06abceaf68e2ad125458bb5f874f Mon Sep 17 00:00:00 2001 From: Suren Baghdasaryan Date: Thu, 13 Feb 2025 14:46:41 -0800 Subject: mm: introduce vma_iter_store_attached() to use with attached vmas vma_iter_store() functions can be used both when adding a new vma and when updating an existing one. However for existing ones we do not need to mark them attached as they are already marked that way. With vma->detached being a separate flag, double-marking a vmas as attached or detached is not an issue because the flag will simply be overwritten with the same value. However once we fold this flag into the refcount later in this series, re-attaching or re-detaching a vma becomes an issue since these operations will be incrementing/decrementing a refcount. Introduce vma_iter_store_new() and vma_iter_store_overwrite() to replace vma_iter_store() and avoid re-attaching a vma during vma update. Add assertions in vma_mark_attached()/vma_mark_detached() to catch invalid usage. Update vma tests to check for vma detached state correctness. Link: https://lkml.kernel.org/r/20250213224655.1680278-5-surenb@google.com Signed-off-by: Suren Baghdasaryan Tested-by: Shivank Garg Link: https://lkml.kernel.org/r/5e19ec93-8307-47c2-bb13-3ddf7150624e@amd.com Reviewed-by: Liam R. Howlett Reviewed-by: Vlastimil Babka 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: Lorenzo Stoakes 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: Shakeel Butt Cc: Sourav Panda Cc: Wei Yang Cc: Will Deacon Cc: Heiko Carstens Cc: Stephen Rothwell Signed-off-by: Andrew Morton --- tools/testing/vma/vma.c | 42 +++++++++++++++++++++++++++++++--------- tools/testing/vma/vma_internal.h | 10 ++++++++++ 2 files changed, 43 insertions(+), 9 deletions(-) (limited to 'tools/testing') diff --git a/tools/testing/vma/vma.c b/tools/testing/vma/vma.c index c7ffa71841ca..11f761769b5b 100644 --- a/tools/testing/vma/vma.c +++ b/tools/testing/vma/vma.c @@ -74,10 +74,22 @@ static struct vm_area_struct *alloc_vma(struct mm_struct *mm, ret->vm_end = end; ret->vm_pgoff = pgoff; ret->__vm_flags = flags; + vma_assert_detached(ret); return ret; } +/* Helper function to allocate a VMA and link it to the tree. */ +static int attach_vma(struct mm_struct *mm, struct vm_area_struct *vma) +{ + int res; + + res = vma_link(mm, vma); + if (!res) + vma_assert_attached(vma); + return res; +} + /* Helper function to allocate a VMA and link it to the tree. */ static struct vm_area_struct *alloc_and_link_vma(struct mm_struct *mm, unsigned long start, @@ -90,7 +102,7 @@ static struct vm_area_struct *alloc_and_link_vma(struct mm_struct *mm, if (vma == NULL) return NULL; - if (vma_link(mm, vma)) { + if (attach_vma(mm, vma)) { vm_area_free(vma); return NULL; } @@ -108,6 +120,7 @@ static struct vm_area_struct *alloc_and_link_vma(struct mm_struct *mm, /* Helper function which provides a wrapper around a merge new VMA operation. */ static struct vm_area_struct *merge_new(struct vma_merge_struct *vmg) { + struct vm_area_struct *vma; /* * For convenience, get prev and next VMAs. Which the new VMA operation * requires. @@ -116,7 +129,11 @@ static struct vm_area_struct *merge_new(struct vma_merge_struct *vmg) vmg->prev = vma_prev(vmg->vmi); vma_iter_next_range(vmg->vmi); - return vma_merge_new_range(vmg); + vma = vma_merge_new_range(vmg); + if (vma) + vma_assert_attached(vma); + + return vma; } /* @@ -125,7 +142,12 @@ static struct vm_area_struct *merge_new(struct vma_merge_struct *vmg) */ static struct vm_area_struct *merge_existing(struct vma_merge_struct *vmg) { - return vma_merge_existing_range(vmg); + struct vm_area_struct *vma; + + vma = vma_merge_existing_range(vmg); + if (vma) + vma_assert_attached(vma); + return vma; } /* @@ -260,8 +282,8 @@ static bool test_simple_merge(void) .pgoff = 1, }; - ASSERT_FALSE(vma_link(&mm, vma_left)); - ASSERT_FALSE(vma_link(&mm, vma_right)); + ASSERT_FALSE(attach_vma(&mm, vma_left)); + ASSERT_FALSE(attach_vma(&mm, vma_right)); vma = merge_new(&vmg); ASSERT_NE(vma, NULL); @@ -285,7 +307,7 @@ static bool test_simple_modify(void) struct vm_area_struct *init_vma = alloc_vma(&mm, 0, 0x3000, 0, flags); VMA_ITERATOR(vmi, &mm, 0x1000); - ASSERT_FALSE(vma_link(&mm, init_vma)); + ASSERT_FALSE(attach_vma(&mm, init_vma)); /* * The flags will not be changed, the vma_modify_flags() function @@ -351,7 +373,7 @@ static bool test_simple_expand(void) .pgoff = 0, }; - ASSERT_FALSE(vma_link(&mm, vma)); + ASSERT_FALSE(attach_vma(&mm, vma)); ASSERT_FALSE(expand_existing(&vmg)); @@ -372,7 +394,7 @@ static bool test_simple_shrink(void) struct vm_area_struct *vma = alloc_vma(&mm, 0, 0x3000, 0, flags); VMA_ITERATOR(vmi, &mm, 0); - ASSERT_FALSE(vma_link(&mm, vma)); + ASSERT_FALSE(attach_vma(&mm, vma)); ASSERT_FALSE(vma_shrink(&vmi, vma, 0, 0x1000, 0)); @@ -1522,11 +1544,11 @@ static bool test_copy_vma(void) vma = alloc_and_link_vma(&mm, 0x3000, 0x5000, 3, flags); vma_new = copy_vma(&vma, 0, 0x2000, 0, &need_locks); - ASSERT_NE(vma_new, vma); ASSERT_EQ(vma_new->vm_start, 0); ASSERT_EQ(vma_new->vm_end, 0x2000); ASSERT_EQ(vma_new->vm_pgoff, 0); + vma_assert_attached(vma_new); cleanup_mm(&mm, &vmi); @@ -1535,6 +1557,7 @@ static bool test_copy_vma(void) vma = alloc_and_link_vma(&mm, 0, 0x2000, 0, flags); vma_next = alloc_and_link_vma(&mm, 0x6000, 0x8000, 6, flags); vma_new = copy_vma(&vma, 0x4000, 0x2000, 4, &need_locks); + vma_assert_attached(vma_new); ASSERT_EQ(vma_new, vma_next); @@ -1576,6 +1599,7 @@ static bool test_expand_only_mode(void) ASSERT_EQ(vma->vm_pgoff, 3); ASSERT_TRUE(vma_write_started(vma)); ASSERT_EQ(vma_iter_addr(&vmi), 0x3000); + vma_assert_attached(vma); cleanup_mm(&mm, &vmi); return true; diff --git a/tools/testing/vma/vma_internal.h b/tools/testing/vma/vma_internal.h index f93f7f74f97b..34277842156c 100644 --- a/tools/testing/vma/vma_internal.h +++ b/tools/testing/vma/vma_internal.h @@ -470,6 +470,16 @@ static inline void vma_lock_init(struct vm_area_struct *vma) vma->vm_lock_seq = UINT_MAX; } +static inline void vma_assert_attached(struct vm_area_struct *vma) +{ + WARN_ON_ONCE(vma->detached); +} + +static inline void vma_assert_detached(struct vm_area_struct *vma) +{ + WARN_ON_ONCE(!vma->detached); +} + static inline void vma_assert_write_locked(struct vm_area_struct *); static inline void vma_mark_attached(struct vm_area_struct *vma) { -- cgit v1.2.3