* [PATCH] mm: lock newly mapped VMA with corrected ordering
@ 2023-07-08 23:04 Hugh Dickins
2023-07-08 23:10 ` Suren Baghdasaryan
0 siblings, 1 reply; 3+ messages in thread
From: Hugh Dickins @ 2023-07-08 23:04 UTC (permalink / raw)
To: Linus Torvalds
Cc: Suren Baghdasaryan, akpm, regressions, bagasdotme, jacobly.alt,
willy, liam.howlett, david, peterx, ldufour, linux-kernel,
linux-mm, linuxppc-dev, linux-arm-kernel, gregkh, regressions,
stable
Lockdep is certainly right to complain about
(&vma->vm_lock->lock){++++}-{3:3}, at: vma_start_write+0x2d/0x3f
but task is already holding lock:
(&mapping->i_mmap_rwsem){+.+.}-{3:3}, at: mmap_region+0x4dc/0x6db
Invert those to the usual ordering.
Fixes: 33313a747e81 ("mm: lock newly mapped VMA which can be modified after it becomes visible")
Cc: stable@vger.kernel.org
Signed-off-by: Hugh Dickins <hughd@google.com>
---
mm/mmap.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/mm/mmap.c b/mm/mmap.c
index 84c71431a527..3eda23c9ebe7 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2809,11 +2809,11 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
if (vma_iter_prealloc(&vmi))
goto close_and_free_vma;
+ /* Lock the VMA since it is modified after insertion into VMA tree */
+ vma_start_write(vma);
if (vma->vm_file)
i_mmap_lock_write(vma->vm_file->f_mapping);
- /* Lock the VMA since it is modified after insertion into VMA tree */
- vma_start_write(vma);
vma_iter_store(&vmi, vma);
mm->map_count++;
if (vma->vm_file) {
--
2.35.3
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] mm: lock newly mapped VMA with corrected ordering
2023-07-08 23:04 [PATCH] mm: lock newly mapped VMA with corrected ordering Hugh Dickins
@ 2023-07-08 23:10 ` Suren Baghdasaryan
2023-07-08 23:22 ` Suren Baghdasaryan
0 siblings, 1 reply; 3+ messages in thread
From: Suren Baghdasaryan @ 2023-07-08 23:10 UTC (permalink / raw)
To: Hugh Dickins
Cc: Linus Torvalds, akpm, regressions, bagasdotme, jacobly.alt,
willy, liam.howlett, david, peterx, ldufour, linux-kernel,
linux-mm, linuxppc-dev, linux-arm-kernel, gregkh, regressions,
stable
On Sat, Jul 8, 2023 at 4:04 PM Hugh Dickins <hughd@google.com> wrote:
>
> Lockdep is certainly right to complain about
> (&vma->vm_lock->lock){++++}-{3:3}, at: vma_start_write+0x2d/0x3f
> but task is already holding lock:
> (&mapping->i_mmap_rwsem){+.+.}-{3:3}, at: mmap_region+0x4dc/0x6db
> Invert those to the usual ordering.
Doh! Thanks Hugh!
I totally forgot to run this with lockdep enabled :(
>
> Fixes: 33313a747e81 ("mm: lock newly mapped VMA which can be modified after it becomes visible")
> Cc: stable@vger.kernel.org
> Signed-off-by: Hugh Dickins <hughd@google.com>
> ---
> mm/mmap.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/mm/mmap.c b/mm/mmap.c
> index 84c71431a527..3eda23c9ebe7 100644
> --- a/mm/mmap.c
> +++ b/mm/mmap.c
> @@ -2809,11 +2809,11 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
> if (vma_iter_prealloc(&vmi))
> goto close_and_free_vma;
>
> + /* Lock the VMA since it is modified after insertion into VMA tree */
> + vma_start_write(vma);
> if (vma->vm_file)
> i_mmap_lock_write(vma->vm_file->f_mapping);
>
> - /* Lock the VMA since it is modified after insertion into VMA tree */
> - vma_start_write(vma);
> vma_iter_store(&vmi, vma);
> mm->map_count++;
> if (vma->vm_file) {
> --
> 2.35.3
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] mm: lock newly mapped VMA with corrected ordering
2023-07-08 23:10 ` Suren Baghdasaryan
@ 2023-07-08 23:22 ` Suren Baghdasaryan
0 siblings, 0 replies; 3+ messages in thread
From: Suren Baghdasaryan @ 2023-07-08 23:22 UTC (permalink / raw)
To: Hugh Dickins
Cc: Linus Torvalds, akpm, regressions, bagasdotme, jacobly.alt,
willy, liam.howlett, david, peterx, ldufour, linux-kernel,
linux-mm, linuxppc-dev, linux-arm-kernel, gregkh, regressions,
stable
On Sat, Jul 8, 2023 at 4:10 PM Suren Baghdasaryan <surenb@google.com> wrote:
>
> On Sat, Jul 8, 2023 at 4:04 PM Hugh Dickins <hughd@google.com> wrote:
> >
> > Lockdep is certainly right to complain about
> > (&vma->vm_lock->lock){++++}-{3:3}, at: vma_start_write+0x2d/0x3f
> > but task is already holding lock:
> > (&mapping->i_mmap_rwsem){+.+.}-{3:3}, at: mmap_region+0x4dc/0x6db
> > Invert those to the usual ordering.
>
> Doh! Thanks Hugh!
> I totally forgot to run this with lockdep enabled :(
I verified both the lockdep warning and the fix. Thanks again, Hugh!
Tested-by: Suren Baghdasaryan <surenb@google.com>
>
> >
> > Fixes: 33313a747e81 ("mm: lock newly mapped VMA which can be modified after it becomes visible")
> > Cc: stable@vger.kernel.org
> > Signed-off-by: Hugh Dickins <hughd@google.com>
> > ---
> > mm/mmap.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/mm/mmap.c b/mm/mmap.c
> > index 84c71431a527..3eda23c9ebe7 100644
> > --- a/mm/mmap.c
> > +++ b/mm/mmap.c
> > @@ -2809,11 +2809,11 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
> > if (vma_iter_prealloc(&vmi))
> > goto close_and_free_vma;
> >
> > + /* Lock the VMA since it is modified after insertion into VMA tree */
> > + vma_start_write(vma);
> > if (vma->vm_file)
> > i_mmap_lock_write(vma->vm_file->f_mapping);
> >
> > - /* Lock the VMA since it is modified after insertion into VMA tree */
> > - vma_start_write(vma);
> > vma_iter_store(&vmi, vma);
> > mm->map_count++;
> > if (vma->vm_file) {
> > --
> > 2.35.3
^ permalink raw reply [flat|nested] 3+ messages in thread
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2023-07-08 23:04 [PATCH] mm: lock newly mapped VMA with corrected ordering Hugh Dickins
2023-07-08 23:10 ` Suren Baghdasaryan
2023-07-08 23:22 ` Suren Baghdasaryan
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