On Thu, 18 May 2023, Jeff Layton wrote: > notify_change can modify the iattr structure. In particular it can can > end up setting ATTR_MODE when ATTR_KILL_SUID is already set, causing a > BUG() if the same iattr is passed to notify_change more than once. > > Make a copy of the struct iattr before calling notify_change. > > Fixes: 34b91dda7124 NFSD: Make nfsd4_setattr() wait before returning NFS4ERR_DELAY > Link: https://bugzilla.redhat.com/show_bug.cgi?id=2207969 > Reported-by: Zhi Li <yieli@xxxxxxxxxx> > Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx> > --- > fs/nfsd/vfs.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c > index c4ef24c5ffd0..ad0c5cd900b1 100644 > --- a/fs/nfsd/vfs.c > +++ b/fs/nfsd/vfs.c > @@ -538,7 +538,9 @@ nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, > > inode_lock(inode); > for (retries = 1;;) { > - host_err = __nfsd_setattr(dentry, iap); > + struct iattr attrs = *iap; > + > + host_err = __nfsd_setattr(dentry, &attrs); I think this needs something to ensure a well meaning by-passer doesn't try to "optimise" it back to the way it was. Maybe make "iap" const? Or add a comment? Or both? NeilBrown > if (host_err != -EAGAIN || !retries--) > break; > if (!nfsd_wait_for_delegreturn(rqstp, inode)) > -- > 2.40.1 > >
