From: Xiubo Li xiubli@redhat.com
When ceph releasing the file_lock it will try to get the inode pointer from the fl->fl_file, which the memory could already be released by another thread in filp_close(). Because in VFS layer the fl->fl_file doesn't increase the file's reference counter.
Will switch to use ceph dedicate lock info to track the inode.
And in ceph_fl_release_lock() we should skip all the operations if the fl->fl_u.ceph_fl.fl_inode is not set, which should come from the request file_lock. And we will set fl->fl_u.ceph_fl.fl_inode when inserting it to the inode lock list, which is when copying the lock.
Cc: stable@vger.kernel.org Cc: Jeff Layton jlayton@kernel.org URL: https://tracker.ceph.com/issues/57986 Signed-off-by: Xiubo Li xiubli@redhat.com --- fs/ceph/locks.c | 20 ++++++++++++++++++-- include/linux/fs.h | 3 +++ 2 files changed, 21 insertions(+), 2 deletions(-)
diff --git a/fs/ceph/locks.c b/fs/ceph/locks.c index b191426bf880..cf78608a3f9a 100644 --- a/fs/ceph/locks.c +++ b/fs/ceph/locks.c @@ -34,18 +34,34 @@ static void ceph_fl_copy_lock(struct file_lock *dst, struct file_lock *src) { struct inode *inode = file_inode(dst->fl_file); atomic_inc(&ceph_inode(inode)->i_filelock_ref); + dst->fl_u.ceph.fl_inode = igrab(inode); }
+/* + * Do not use the 'fl->fl_file' in release function, which + * is possibly already released by another thread. + */ static void ceph_fl_release_lock(struct file_lock *fl) { - struct inode *inode = file_inode(fl->fl_file); - struct ceph_inode_info *ci = ceph_inode(inode); + struct inode *inode = fl->fl_u.ceph.fl_inode; + struct ceph_inode_info *ci; + + /* + * If inode is NULL it should be a request file_lock, + * nothing we can do. + */ + if (!inode) + return; + + ci = ceph_inode(inode); if (atomic_dec_and_test(&ci->i_filelock_ref)) { /* clear error when all locks are released */ spin_lock(&ci->i_ceph_lock); ci->i_ceph_flags &= ~CEPH_I_ERROR_FILELOCK; spin_unlock(&ci->i_ceph_lock); } + fl->fl_u.ceph.fl_inode = NULL; + iput(inode); }
static const struct file_lock_operations ceph_fl_lock_ops = { diff --git a/include/linux/fs.h b/include/linux/fs.h index 7b52fdfb6da0..6106374f5257 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1119,6 +1119,9 @@ struct file_lock { int state; /* state of grant or error if -ve */ unsigned int debug_id; } afs; + struct { + struct inode *fl_inode; + } ceph; } fl_u; } __randomize_layout;