Re: [PATCH] netfs: Fix kernel BUG in netfs_limit_iter() for ITER_KVEC iterators

[Christian Brauner]

On Sat, 07 Mar 2026 14:30:41 +0530, Deepanshu Kartikey wrote:
> When a process crashes and the kernel writes a core dump to a 9P
> filesystem, __kernel_write() creates an ITER_KVEC iterator. This
> iterator reaches netfs_limit_iter() via netfs_unbuffered_write(), which
> only handles ITER_FOLIOQ, ITER_BVEC and ITER_XARRAY iterator types,
> hitting the BUG() for any other type.
> 
> Fix this by adding netfs_limit_kvec() following the same pattern as
> netfs_limit_bvec(), since both kvec and bvec are simple segment arrays
> with pointer and length fields. Dispatch it from netfs_limit_iter() when
> the iterator type is ITER_KVEC.
> 
> [...]

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 kernel BUG in netfs_limit_iter() for ITER_KVEC iterators
      https://git.kernel.org/vfs/vfs/c/67e467a11f62