Fix races around the access to ->s_options
Put generic_show_options read access to s_options under rcu_read_lock,
split save_mount_options() into "we are setting it the first time"
(uses in foo_fill_super()) and "we are relacing and freeing the old one",
synchronize_rcu() before kfree() in the latter.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/afs/super.c b/fs/afs/super.c
index 2753f16..76828e5 100644
--- a/fs/afs/super.c
+++ b/fs/afs/super.c
@@ -408,17 +408,17 @@
deactivate_locked_super(sb);
goto error;
}
- sb->s_options = new_opts;
+ save_mount_options(sb, new_opts);
sb->s_flags |= MS_ACTIVE;
} else {
_debug("reuse");
- kfree(new_opts);
ASSERTCMP(sb->s_flags, &, MS_ACTIVE);
}
simple_set_mnt(mnt, sb);
afs_put_volume(params.volume);
afs_put_cell(params.cell);
+ kfree(new_opts);
_leave(" = 0 [%p]", sb);
return 0;