On Fri, 2022-05-13 at 09:36 -0400, Benjamin Coddington wrote:
> ..which will fix up trying to free uninitialized nfs4_label:
>
> PID: 790 TASK: ffff88811b43c000 CPU: 0 COMMAND: "ls"
> #0 [ffffc90000857920] panic at ffffffff81b9bfde
> #1 [ffffc900008579c0] do_trap at ffffffff81023a9b
> #2 [ffffc90000857a10] do_error_trap at ffffffff81023b78
> #3 [ffffc90000857a58] exc_stack_segment at ffffffff81be1f45
> #4 [ffffc90000857a80] asm_exc_stack_segment at ffffffff81c009de
> #5 [ffffc90000857b08] nfs_lookup at ffffffffa0302322 [nfs]
> #6 [ffffc90000857b70] __lookup_slow at ffffffff813a4a5f
> #7 [ffffc90000857c60] walk_component at ffffffff813a86c4
> #8 [ffffc90000857cb8] path_lookupat at ffffffff813a9553
> #9 [ffffc90000857cf0] filename_lookup at ffffffff813ab86b
>
> Fixes: 9558a007dbc3 ("NFS: Remove the label from the nfs4_lookup_res
> struct")
> Signed-off-by: Benjamin Coddington <bcodding@xxxxxxxxxx>
> ---
> fs/nfs/nfs4proc.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
> index a79f66432bd3..4566280e6ff2 100644
> --- a/fs/nfs/nfs4proc.c
> +++ b/fs/nfs/nfs4proc.c
> @@ -4235,6 +4235,7 @@ static int nfs4_get_referral(struct rpc_clnt
> *client, struct inode *dir,
> int status = -ENOMEM;
> struct page *page = NULL;
> struct nfs4_fs_locations *locations = NULL;
> + struct nfs4_label *label = fattr->label;
>
> page = alloc_page(GFP_KERNEL);
> if (page == NULL)
> @@ -4263,6 +4264,7 @@ static int nfs4_get_referral(struct rpc_clnt
> *client, struct inode *dir,
>
> /* replace the lookup nfs_fattr with the locations nfs_fattr
> */
> memcpy(fattr, &locations->fattr, sizeof(struct nfs_fattr));
> + fattr->label = label;
> memset(fhandle, 0, sizeof(struct nfs_fh));
> out:
> if (page)
Thanks for finding this, but wouldn't it be better just to decode the
fattr in place instead of decoding it into locations->fattr and then
doing a memcpy() to get it placed correctly?
i.e. add a level of indirection in struct nfs4_fs_locations so that
nfs4_xdr_dec_fs_locations() just uses our fattr instead of its own.
--
Trond Myklebust
Linux NFS client maintainer, Hammerspace
trond.myklebust@xxxxxxxxxxxxxxx
