[PATCH v2] netfs: Fix netfs_page_mkwrite() to check folio->mapping is valid

[Christian Brauner]

On Tue, 25 Jun 2024 13:29:06 +0100, David Howells wrote:
> 
> Fix netfs_page_mkwrite() to check that folio->mapping is valid once it has
> taken the folio lock (as filemap_page_mkwrite() does).  Without this,
> generic/247 occasionally oopses with something like the following:
> 
>     BUG: kernel NULL pointer dereference, address: 0000000000000000
>     #PF: supervisor read access in kernel mode
>     #PF: error_code(0x0000) - not-present page
> 
> [...]

Applied to the vfs.fixes branch of the vfs/vfs.git tree.
Patches in the vfs.fixes branch should appear in linux-next soon.

Please report any outstanding bugs that were missed during review in a
new review to the original patch series allowing us to drop it.

It's encouraged to provide Acked-bys and Reviewed-bys even though the
patch has now been applied. If possible patch trailers will be updated.

Note that commit hashes shown below are subject to change due to rebase,
trailer updates or similar. If in doubt, please check the listed branch.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git
branch: vfs.fixes

[1/1] netfs: Fix netfs_page_mkwrite() to check folio->mapping is valid
      https://git.kernel.org/vfs/vfs/c/a81c98bfa40c