Hi Bruce-
> On Aug 5, 2020, at 3:10 PM, bfields@xxxxxxxxxxxx wrote:
>
> From: "J. Bruce Fields" <bfields@xxxxxxxxxx>
>
> If an NFSv2/v3 client breaks an NFSv4 client's delegation, it will hit a
> NULL dereference in nfsd_breaker_owns_lease().
>
> Easily reproduceable with for example
>
> mount -overs=4.2 server:/export /mnt/
> sleep 1h </mnt/file &
> mount -overs=3 server:/export /mnt2/
> touch /mnt2/file
>
> Reported-by: Robert Dinse <nanook@xxxxxxxxxx>
> Fixes: 28df3d1539de50 ("nfsd: clients don't need to break their own delegations")
May I add
BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=208807
And send this in the first NFSD v5.9 -rc pull request?
> Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx>
> ---
> fs/nfsd/nfs4state.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index 9fc0a1b9e4dd..45f3832d70d4 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -4597,6 +4597,8 @@ static bool nfsd_breaker_owns_lease(struct file_lock *fl)
> if (!i_am_nfsd())
> return NULL;
> rqst = kthread_data(current);
> + if (!rqst->rq_lease_breaker)
> + return NULL;
> clp = *(rqst->rq_lease_breaker);
> return dl->dl_stid.sc_client == clp;
> }
> --
> 2.26.2
>
--
Chuck Lever
