80019f1138
Syzkaller reports a null pointer dereference in fuse_test_super() that is caused by sb->s_fs_info being NULL. This is due to the fact that fuse_fill_super() is initializing s_fs_info, which is too late, it's already on the fs_supers list. The initialization needs to be done in sget_fc() with the sb_lock held. Move allocation of fuse_mount and fuse_conn from fuse_fill_super() into fuse_get_tree(). After this ->kill_sb() will always be called with non-NULL ->s_fs_info, hence fuse_mount_destroy() can drop the test for non-NULL "fm". Reported-by: syzbot+74a15f02ccb51f398601@syzkaller.appspotmail.com Fixes: 5d5b74aa9c76 ("fuse: allow sharing existing sb") Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.