On Sat, Oct 26, 2024 at 12:02 PM <cel@xxxxxxxxxx> wrote:
>
> From: Chuck Lever <chuck.lever@xxxxxxxxxx>
>
> Ensure the refcount and async_copies fields are initialized early.
> cleanup_async_copy() will reference these fields if an error occurs
> in nfsd4_copy(). If they are not correctly initialized, at the very
> least, a refcount underflow occurs.
>
> Reported-by: Olga Kornievskaia <okorniev@xxxxxxxxxx>
> Fixes: aadc3bbea163 ("NFSD: Limit the number of concurrent async COPY operations")
> Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
> ---
> fs/nfsd/nfs4proc.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
> index b5a6bf4f459f..5fd1ce3fc8fb 100644
> --- a/fs/nfsd/nfs4proc.c
> +++ b/fs/nfsd/nfs4proc.c
> @@ -1841,14 +1841,14 @@ nfsd4_copy(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
> if (!async_copy)
> goto out_err;
> async_copy->cp_nn = nn;
> + INIT_LIST_HEAD(&async_copy->copies);
> + refcount_set(&async_copy->refcount, 1);
> /* Arbitrary cap on number of pending async copy operations */
> if (atomic_inc_return(&nn->pending_async_copies) >
> (int)rqstp->rq_pool->sp_nrthreads) {
> atomic_dec(&nn->pending_async_copies);
> goto out_err;
> }
> - INIT_LIST_HEAD(&async_copy->copies);
> - refcount_set(&async_copy->refcount, 1);
> async_copy->cp_src = kmalloc(sizeof(*async_copy->cp_src), GFP_KERNEL);
> if (!async_copy->cp_src)
> goto out_err;
> --
No more warning after this patch when we hit the copy limit.
Tested-by: Olga Kornievskaia <okorniev@xxxxxxxxxx>
> 2.47.0
>
>
