[PATCH 6.1] Revert "fork: defer linking file vma until vma is fully initialized"

[PATCH 6.1] Revert "fork: defer linking file vma until vma is fully initialized"

[Sam James]

This reverts commit 0c42f7e039aba3de6d7dbf92da708e2b2ecba557.

The backport is incomplete and causes xfstests failures. The consequences
of the incomplete backport seem worse than the original issue, so pick
the lesser evil and revert until a full backport is ready.

Link: https://lore.kernel.org/stable/20240604004751.3883227-1-leah.rumancik@gmail.com/
Reported-by: Leah Rumancik <leah.rumancik@gmail.com>
Signed-off-by: Sam James <sam@gentoo.org>
---
 kernel/fork.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/kernel/fork.c b/kernel/fork.c
index 7e9a5919299b4..85617928041cf 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -662,15 +662,6 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
 		} else if (anon_vma_fork(tmp, mpnt))
 			goto fail_nomem_anon_vma_fork;
 		tmp->vm_flags &= ~(VM_LOCKED | VM_LOCKONFAULT);
-		/*
-		 * Copy/update hugetlb private vma information.
-		 */
-		if (is_vm_hugetlb_page(tmp))
-			hugetlb_dup_vma_private(tmp);
-
-		if (tmp->vm_ops && tmp->vm_ops->open)
-			tmp->vm_ops->open(tmp);
-
 		file = tmp->vm_file;
 		if (file) {
 			struct address_space *mapping = file->f_mapping;
@@ -687,6 +678,12 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
 			i_mmap_unlock_write(mapping);
 		}
 
+		/*
+		 * Copy/update hugetlb private vma information.
+		 */
+		if (is_vm_hugetlb_page(tmp))
+			hugetlb_dup_vma_private(tmp);
+
 		/* Link the vma into the MT */
 		mas.index = tmp->vm_start;
 		mas.last = tmp->vm_end - 1;
@@ -698,6 +695,9 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
 		if (!(tmp->vm_flags & VM_WIPEONFORK))
 			retval = copy_page_range(tmp, mpnt);
 
+		if (tmp->vm_ops && tmp->vm_ops->open)
+			tmp->vm_ops->open(tmp);
+
 		if (retval)
 			goto loop_out;
 	}
-- 
2.45.2

Re: [PATCH 6.1] Revert "fork: defer linking file vma until vma is fully initialized"

[Greg KH]

On Fri, Jun 14, 2024 at 09:40:28AM +0100, Sam James wrote:
> This reverts commit 0c42f7e039aba3de6d7dbf92da708e2b2ecba557.
> 
> The backport is incomplete and causes xfstests failures. The consequences
> of the incomplete backport seem worse than the original issue, so pick
> the lesser evil and revert until a full backport is ready.
> 
> Link: https://lore.kernel.org/stable/20240604004751.3883227-1-leah.rumancik@gmail.com/
> Reported-by: Leah Rumancik <leah.rumancik@gmail.com>
> Signed-off-by: Sam James <sam@gentoo.org>
> ---
>  kernel/fork.c | 18 +++++++++---------
>  1 file changed, 9 insertions(+), 9 deletions(-)

Both reverts now queued up, thanks.

greg k-h