On Mon, 2023-03-27 at 13:14 +0000, Chuck Lever III wrote: > > > On Mar 27, 2023, at 6:21 AM, Jeff Layton <jlayton@xxxxxxxxxx> wrote: > > > > For ops with "trivial" replies, nfsd4_encode_operation will shortcut > > most of the encoding work and skip to just marshalling up the status. > > One of the things it skips is calling op_release. This could cause a > > memory leak in the layoutget codepath if there is an error at an > > inopportune time. > > > > Have the compound processing engine always call op_release, even when > > op_func sets an error in op->status. With this change, we also need > > nfsd4_block_get_device_info_scsi to set the gd_device pointer to NULL > > on error to avoid a double free. > > > > Reported-by: Zhi Li <yieli@xxxxxxxxxx> > > Link: https://bugzilla.redhat.com/show_bug.cgi?id=2181403 > > Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx> > > Thanks, Jeff. > > May I add: Fixes: 34b1744c91cc ("nfsd4: define ->op_release for > compound ops") ? > I've seen some problems with this patch in testing and I have a fix forthcoming (once I finish testing it): The root cause is the OPDESC() function which can walk off the end of the nfsd4_ops array when passed a large value (like OP_ILLEGAL). I think we'll want to fix that to do something more sane before merging this patch. > > > --- > > fs/nfsd/blocklayout.c | 1 + > > fs/nfsd/nfs4xdr.c | 13 +++++++------ > > 2 files changed, 8 insertions(+), 6 deletions(-) > > > > diff --git a/fs/nfsd/blocklayout.c b/fs/nfsd/blocklayout.c > > index 04697f8dc37d..01d7fd108cf3 100644 > > --- a/fs/nfsd/blocklayout.c > > +++ b/fs/nfsd/blocklayout.c > > @@ -297,6 +297,7 @@ nfsd4_block_get_device_info_scsi(struct super_block *sb, > > > > out_free_dev: > > kfree(dev); > > + gdp->gd_device = NULL; > > return ret; > > } > > > > diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c > > index e12e5a4ad502..6b675fbdabd0 100644 > > --- a/fs/nfsd/nfs4xdr.c > > +++ b/fs/nfsd/nfs4xdr.c > > @@ -5402,7 +5402,7 @@ nfsd4_encode_operation(struct nfsd4_compoundres *resp, struct nfsd4_op *op) > > p = xdr_reserve_space(xdr, 8); > > if (!p) { > > WARN_ON_ONCE(1); > > - return; > > + goto release; > > } > > *p++ = cpu_to_be32(op->opnum); > > post_err_offset = xdr->buf->len; > > @@ -5418,8 +5418,6 @@ nfsd4_encode_operation(struct nfsd4_compoundres *resp, struct nfsd4_op *op) > > op->status = encoder(resp, op->status, &op->u); > > if (op->status) > > trace_nfsd_compound_encode_err(rqstp, op->opnum, op->status); > > - if (opdesc && opdesc->op_release) > > - opdesc->op_release(&op->u); > > xdr_commit_encode(xdr); > > > > /* nfsd4_check_resp_size guarantees enough room for error status */ > > @@ -5460,11 +5458,14 @@ nfsd4_encode_operation(struct nfsd4_compoundres *resp, struct nfsd4_op *op) > > } > > status: > > *p = op->status; > > +release: > > + if (opdesc && opdesc->op_release) > > + opdesc->op_release(&op->u); > > } > > > > -/* > > - * Encode the reply stored in the stateowner reply cache > > - * > > +/* > > + * Encode the reply stored in the stateowner reply cache > > + * > > * XDR note: do not encode rp->rp_buflen: the buffer contains the > > * previously sent already encoded operation. > > */ > > -- > > 2.39.2 > > > > -- > Chuck Lever > > -- Jeff Layton <jlayton@xxxxxxxxxx>
