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) {
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
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
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