On Fri, 2018-07-13 at 17:22 +0300, Amir Goldstein wrote: > nfsd and lockd call vfs_lock_file() to lock/unlock the inode > returned by locks_inode(file). > > Many places in nfsd/lockd code use the inode returned by > file_inode(file) for lock manipulation. With Overlayfs, file_inode() > (the underlying inode) is not the same object as locks_inode() (the > overlay inode). This can result in "Leaked POSIX lock" messages > and eventually to a kernel crash as reported by Eddie Horng: > https://marc.info/?l=linux-unionfs&m=153086643202072&w=2 > > Fix all the call sites in nfsd/lockd that should use locks_inode(). > This is a correctness bug that manifested when overlayfs gained > NFS export support in v4.16. > > Reported-by: Eddie Horng <eddiehorng.tw@xxxxxxxxx> > Tested-by: Eddie Horng <eddiehorng.tw@xxxxxxxxx> > Cc: Jeff Layton <jlayton@xxxxxxxxxx> > Fixes: 8383f1748829 ("ovl: wire up NFS export operations") > Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx> > --- > > Hi Bruce, > > For the purpose of locks, nfsd/lockd should look at locks_inode() > just like vfs lock functions. > > Hopefully, Miklos's work on stacked overlayfs file operations will > be merged soon and locks_inode() will become the same as file_inode(), > but we will still need this fix for stable kernels v4.16 through v4.18. > > Beyond testing by Eddie, I also verified no regressions when running > nfstest with exported overlayfs. > > Thanks, > Amir. > > fs/lockd/clntlock.c | 2 +- > fs/lockd/clntproc.c | 2 +- > fs/lockd/svclock.c | 16 ++++++++-------- > fs/lockd/svcsubs.c | 4 ++-- > fs/nfsd/nfs4state.c | 2 +- > include/linux/lockd/lockd.h | 4 ++-- > 6 files changed, 15 insertions(+), 15 deletions(-) > > diff --git a/fs/lockd/clntlock.c b/fs/lockd/clntlock.c > index 96c1d14c18f1..c2a128678e6e 100644 > --- a/fs/lockd/clntlock.c > +++ b/fs/lockd/clntlock.c > @@ -187,7 +187,7 @@ __be32 nlmclnt_grant(const struct sockaddr *addr, const struct nlm_lock *lock) > continue; > if (!rpc_cmp_addr(nlm_addr(block->b_host), addr)) > continue; > - if (nfs_compare_fh(NFS_FH(file_inode(fl_blocked->fl_file)) ,fh) != 0) > + if (nfs_compare_fh(NFS_FH(locks_inode(fl_blocked->fl_file)), fh) != 0) > continue; > /* Alright, we found a lock. Set the return status > * and wake up the caller > diff --git a/fs/lockd/clntproc.c b/fs/lockd/clntproc.c > index a2c0dfc6fdc0..d20b92f271c2 100644 > --- a/fs/lockd/clntproc.c > +++ b/fs/lockd/clntproc.c > @@ -128,7 +128,7 @@ static void nlmclnt_setlockargs(struct nlm_rqst *req, struct file_lock *fl) > char *nodename = req->a_host->h_rpcclnt->cl_nodename; > > nlmclnt_next_cookie(&argp->cookie); > - memcpy(&lock->fh, NFS_FH(file_inode(fl->fl_file)), sizeof(struct nfs_fh)); > + memcpy(&lock->fh, NFS_FH(locks_inode(fl->fl_file)), sizeof(struct nfs_fh)); > lock->caller = nodename; > lock->oh.data = req->a_owner; > lock->oh.len = snprintf(req->a_owner, sizeof(req->a_owner), "%u@%s", > diff --git a/fs/lockd/svclock.c b/fs/lockd/svclock.c > index 3701bccab478..74330daeab71 100644 > --- a/fs/lockd/svclock.c > +++ b/fs/lockd/svclock.c > @@ -405,8 +405,8 @@ nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file, > __be32 ret; > > dprintk("lockd: nlmsvc_lock(%s/%ld, ty=%d, pi=%d, %Ld-%Ld, bl=%d)\n", > - file_inode(file->f_file)->i_sb->s_id, > - file_inode(file->f_file)->i_ino, > + locks_inode(file->f_file)->i_sb->s_id, > + locks_inode(file->f_file)->i_ino, > lock->fl.fl_type, lock->fl.fl_pid, > (long long)lock->fl.fl_start, > (long long)lock->fl.fl_end, > @@ -511,8 +511,8 @@ nlmsvc_testlock(struct svc_rqst *rqstp, struct nlm_file *file, > __be32 ret; > > dprintk("lockd: nlmsvc_testlock(%s/%ld, ty=%d, %Ld-%Ld)\n", > - file_inode(file->f_file)->i_sb->s_id, > - file_inode(file->f_file)->i_ino, > + locks_inode(file->f_file)->i_sb->s_id, > + locks_inode(file->f_file)->i_ino, > lock->fl.fl_type, > (long long)lock->fl.fl_start, > (long long)lock->fl.fl_end); > @@ -566,8 +566,8 @@ nlmsvc_unlock(struct net *net, struct nlm_file *file, struct nlm_lock *lock) > int error; > > dprintk("lockd: nlmsvc_unlock(%s/%ld, pi=%d, %Ld-%Ld)\n", > - file_inode(file->f_file)->i_sb->s_id, > - file_inode(file->f_file)->i_ino, > + locks_inode(file->f_file)->i_sb->s_id, > + locks_inode(file->f_file)->i_ino, > lock->fl.fl_pid, > (long long)lock->fl.fl_start, > (long long)lock->fl.fl_end); > @@ -595,8 +595,8 @@ nlmsvc_cancel_blocked(struct net *net, struct nlm_file *file, struct nlm_lock *l > int status = 0; > > dprintk("lockd: nlmsvc_cancel(%s/%ld, pi=%d, %Ld-%Ld)\n", > - file_inode(file->f_file)->i_sb->s_id, > - file_inode(file->f_file)->i_ino, > + locks_inode(file->f_file)->i_sb->s_id, > + locks_inode(file->f_file)->i_ino, > lock->fl.fl_pid, > (long long)lock->fl.fl_start, > (long long)lock->fl.fl_end); > diff --git a/fs/lockd/svcsubs.c b/fs/lockd/svcsubs.c > index 4ec3d6e03e76..899360ba3b84 100644 > --- a/fs/lockd/svcsubs.c > +++ b/fs/lockd/svcsubs.c > @@ -44,7 +44,7 @@ static inline void nlm_debug_print_fh(char *msg, struct nfs_fh *f) > > static inline void nlm_debug_print_file(char *msg, struct nlm_file *file) > { > - struct inode *inode = file_inode(file->f_file); > + struct inode *inode = locks_inode(file->f_file); > > dprintk("lockd: %s %s/%ld\n", > msg, inode->i_sb->s_id, inode->i_ino); > @@ -414,7 +414,7 @@ nlmsvc_match_sb(void *datap, struct nlm_file *file) > { > struct super_block *sb = datap; > > - return sb == file_inode(file->f_file)->i_sb; > + return sb == locks_inode(file->f_file)->i_sb; > } > > /** > diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c > index 857141446d6b..4a17fad93411 100644 > --- a/fs/nfsd/nfs4state.c > +++ b/fs/nfsd/nfs4state.c > @@ -6293,7 +6293,7 @@ check_for_locks(struct nfs4_file *fp, struct nfs4_lockowner *lowner) > return status; > } > > - inode = file_inode(filp); > + inode = locks_inode(filp); > flctx = inode->i_flctx; > > if (flctx && !list_empty_careful(&flctx->flc_posix)) { > diff --git a/include/linux/lockd/lockd.h b/include/linux/lockd/lockd.h > index 4fd95dbeb52f..b065ef406770 100644 > --- a/include/linux/lockd/lockd.h > +++ b/include/linux/lockd/lockd.h > @@ -299,7 +299,7 @@ int nlmsvc_unlock_all_by_ip(struct sockaddr *server_addr); > > static inline struct inode *nlmsvc_file_inode(struct nlm_file *file) > { > - return file_inode(file->f_file); > + return locks_inode(file->f_file); > } > fwiw, I think the above delta turns out to be the real fix here, as that affects nlm_file_inuse. > static inline int __nlm_privileged_request4(const struct sockaddr *sap) > @@ -359,7 +359,7 @@ static inline int nlm_privileged_requester(const struct svc_rqst *rqstp) > static inline int nlm_compare_locks(const struct file_lock *fl1, > const struct file_lock *fl2) > { > - return file_inode(fl1->fl_file) == file_inode(fl2->fl_file) > + return locks_inode(fl1->fl_file) == locks_inode(fl2->fl_file) > && fl1->fl_pid == fl2->fl_pid > && fl1->fl_owner == fl2->fl_owner > && fl1->fl_start == fl2->fl_start I think this looks OK. I was a bit hesitant as I wasn't sure whether this would change the filehandles presented by the nfsd, but I don't think it will. Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
