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BACKPORT: FROMGIT: mm: mark vma as detached until it's added into vma tree

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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 <surenb@google.com>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Tested-by: Shivank Garg <shivankg@amd.com>
  Link: https://lkml.kernel.org/r/5e19ec93-8307-47c2-bb13-3ddf7150624e@amd.com
Cc: Christian Brauner <brauner@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Klara Modin <klarasmodin@gmail.com>
Cc: Lokesh Gidra <lokeshgidra@google.com>
Cc: Mateusz Guzik <mjguzik@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Minchan Kim <minchan@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: "Paul E . McKenney" <paulmck@kernel.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Sourav Panda <souravpanda@google.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

(cherry picked from commit 286750a6443552abad64c66ac96e629c4516bb3b
[surenb: resolved conflict due to the reattach_vmas() being moved from
vma.h to vma.c]
https: //git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-unstable)
Bug: 322132947
Change-Id: I7361060f5e3ef392848f835db4c0c0f74de12ea7
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
This commit is contained in:
Suren Baghdasaryan
2025-02-13 14:46:40 -08:00
committed by Giuliano Procida
parent e1e4842c07
commit 74cc099459
6 changed files with 42 additions and 16 deletions
Download Patch File Download Diff File Expand all files Collapse all files
include/linux/mm.h
+20 -7
View File
@@ -808,12 +808,21 @@ 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)
@@ -844,8 +853,8 @@ 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)
@@ -878,7 +887,10 @@ 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);
}
@@ -1073,6 +1085,7 @@ 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;
}
kernel/fork.c
+4
View File
@@ -473,6 +473,10 @@ 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);
mm/memory.c
+1 -1
View File
@@ -6255,7 +6255,7 @@ 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 */
mm/vma.c
+2 -2
View File
@@ -244,7 +244,7 @@ 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);
@@ -1237,7 +1237,7 @@ 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;
mm/vma.h
+3 -1
View File
@@ -162,6 +162,7 @@ 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;
}
@@ -221,7 +222,7 @@ static inline 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);
}
@@ -474,6 +475,7 @@ 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)
tools/testing/vma/vma_internal.h
+12 -5
View File
@@ -405,12 +405,16 @@ 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;
@@ -421,7 +425,8 @@ 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);
}
@@ -447,6 +452,8 @@ 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;
}