From: Suren Baghdasaryan <surenb@google•com>
To: akpm@linux-foundation•org
Cc: michel@lespinasse•org, joelaf@google•com, songliubraving@fb•com,
mhocko@suse•com, leewalsh@google•com, david@redhat•com,
peterz@infradead•org, bigeasy@linutronix•de, peterx@redhat•com,
dhowells@redhat•com, linux-mm@kvack•org, edumazet@google•com,
jglisse@google•com, punit.agrawal@bytedance•com, will@kernel•org,
arjunroy@google•com, dave@stgolabs•net, minchan@google•com,
x86@kernel•org, hughd@google•com, willy@infradead•org,
gurua@google•com, mingo@redhat•com,
linux-arm-kernel@lists•infradead.org, rientjes@google•com,
axelrasmussen@google•com, kernel-team@android•com,
soheil@google•com, paulmck@kernel•org, jannh@google•com,
liam.howlett@oracle•com, shakeelb@google•com, luto@kernel•org,
gthelen@google•com, ldufour@linux•ibm.com, surenb@google•com,
vbabka@suse•cz, posk@google•com, lstoakes@gmail•com,
peterjung1337@gmail•com, linuxppc-dev@lists•ozlabs.org,
kent.overstreet@linux•dev, linux-kernel@vger•kernel.org,
hannes@cmpxchg•org, tatashin@google•com,
mgorman@techsingularity•net, rp pt@kernel•org
Subject: [PATCH v2 20/33] mm/mmap: write-lock adjacent VMAs if they can grow into unmapped area
Date: Fri, 27 Jan 2023 11:40:57 -0800 [thread overview]
Message-ID: <20230127194110.533103-21-surenb@google.com> (raw)
In-Reply-To: <20230127194110.533103-1-surenb@google.com>
While unmapping VMAs, adjacent VMAs might be able to grow into the area
being unmapped. In such cases write-lock adjacent VMAs to prevent this
growth.
Signed-off-by: Suren Baghdasaryan <surenb@google•com>
---
mm/mmap.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/mm/mmap.c b/mm/mmap.c
index 57cb3a2ac9b1..3baf218836bb 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2399,11 +2399,13 @@ do_vmi_align_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma,
* down_read(mmap_lock) and collide with the VMA we are about to unmap.
*/
if (downgrade) {
- if (next && (next->vm_flags & VM_GROWSDOWN))
+ if (next && (next->vm_flags & VM_GROWSDOWN)) {
+ vma_start_write(next);
downgrade = false;
- else if (prev && (prev->vm_flags & VM_GROWSUP))
+ } else if (prev && (prev->vm_flags & VM_GROWSUP)) {
+ vma_start_write(prev);
downgrade = false;
- else
+ } else
mmap_write_downgrade(mm);
}
--
2.39.1
next prev parent reply other threads:[~2023-01-27 20:00 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-27 19:40 [PATCH v2 00/33] Per-VMA locks Suren Baghdasaryan
2023-01-27 19:40 ` [PATCH v2 01/33] maple_tree: Be more cautious about dead nodes Suren Baghdasaryan
2023-01-27 19:40 ` [PATCH v2 02/33] maple_tree: Detect dead nodes in mas_start() Suren Baghdasaryan
2023-01-27 19:40 ` [PATCH v2 03/33] maple_tree: Fix freeing of nodes in rcu mode Suren Baghdasaryan
2023-01-27 19:40 ` [PATCH v2 04/33] maple_tree: remove extra smp_wmb() from mas_dead_leaves() Suren Baghdasaryan
2023-01-27 19:40 ` [PATCH v2 05/33] maple_tree: Fix write memory barrier of nodes once dead for RCU mode Suren Baghdasaryan
2023-01-27 19:40 ` [PATCH v2 06/33] maple_tree: Add smp_rmb() to dead node detection Suren Baghdasaryan
2023-01-27 19:40 ` [PATCH v2 07/33] mm: Enable maple tree RCU mode by default Suren Baghdasaryan
2023-01-27 19:40 ` [PATCH v2 08/33] mm: introduce CONFIG_PER_VMA_LOCK Suren Baghdasaryan
2023-01-27 19:40 ` [PATCH v2 09/33] mm: rcu safe VMA freeing Suren Baghdasaryan
2023-01-27 19:40 ` [PATCH v2 10/33] mm: move mmap_lock assert function definitions Suren Baghdasaryan
2023-01-27 19:40 ` [PATCH v2 11/33] mm: add per-VMA lock and helper functions to control it Suren Baghdasaryan
2023-01-27 19:40 ` [PATCH v2 12/33] mm: mark VMA as being written when changing vm_flags Suren Baghdasaryan
2023-01-27 19:40 ` [PATCH v2 13/33] mm/mmap: move VMA locking before vma_adjust_trans_huge call Suren Baghdasaryan
2023-01-27 19:40 ` [PATCH v2 14/33] mm/khugepaged: write-lock VMA while collapsing a huge page Suren Baghdasaryan
2023-01-27 19:40 ` [PATCH v2 15/33] mm/mmap: write-lock VMAs before merging, splitting or expanding them Suren Baghdasaryan
2023-01-27 19:40 ` [PATCH v2 16/33] mm/mmap: write-lock VMA before shrinking or expanding it Suren Baghdasaryan
2023-01-27 19:40 ` [PATCH v2 17/33] mm/mremap: write-lock VMA while remapping it to a new address range Suren Baghdasaryan
2023-01-27 19:40 ` [PATCH v2 18/33] mm: write-lock VMAs before removing them from VMA tree Suren Baghdasaryan
2023-01-27 19:40 ` [PATCH v2 19/33] mm: conditionally write-lock VMA in free_pgtables Suren Baghdasaryan
2023-01-27 19:40 ` Suren Baghdasaryan [this message]
2023-01-27 19:40 ` [PATCH v2 21/33] kernel/fork: assert no VMA readers during its destruction Suren Baghdasaryan
2023-01-27 19:40 ` [PATCH v2 22/33] mm/mmap: prevent pagefault handler from racing with mmu_notifier registration Suren Baghdasaryan
2023-01-27 19:41 ` [PATCH v2 23/33] mm: introduce lock_vma_under_rcu to be used from arch-specific code Suren Baghdasaryan
2023-01-27 19:41 ` [PATCH v2 24/33] mm: fall back to mmap_lock if vma->anon_vma is not yet set Suren Baghdasaryan
2023-01-27 19:41 ` [PATCH v2 25/33] mm: add FAULT_FLAG_VMA_LOCK flag Suren Baghdasaryan
2023-01-27 19:41 ` [PATCH v2 26/33] mm: prevent do_swap_page from handling page faults under VMA lock Suren Baghdasaryan
2023-01-27 19:41 ` [PATCH v2 27/33] mm: prevent userfaults to be handled under per-vma lock Suren Baghdasaryan
2023-01-27 19:41 ` [PATCH v2 28/33] mm: introduce per-VMA lock statistics Suren Baghdasaryan
2023-01-27 19:41 ` [PATCH v2 29/33] x86/mm: try VMA lock-based page fault handling first Suren Baghdasaryan
2023-01-27 19:41 ` [PATCH v2 30/33] arm64/mm: " Suren Baghdasaryan
2023-01-27 19:41 ` [PATCH v2 31/33] powerc/mm: " Suren Baghdasaryan
2023-01-27 19:41 ` [PATCH v2 32/33] mm/mmap: free vm_area_struct without call_rcu in exit_mmap Suren Baghdasaryan
2023-01-27 19:41 ` [PATCH v2 33/33] mm: separate vma->lock from vm_area_struct Suren Baghdasaryan
2023-01-27 22:51 ` [PATCH v2 00/33] Per-VMA locks Andrew Morton
2023-01-27 23:26 ` Matthew Wilcox
2023-01-28 0:00 ` Suren Baghdasaryan
2023-02-14 16:47 ` Suren Baghdasaryan
2023-02-15 17:32 ` [External] " Punit Agrawal
2023-02-15 17:39 ` Suren Baghdasaryan
2023-02-28 12:06 ` Punit Agrawal
2023-02-28 18:08 ` Suren Baghdasaryan
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