Re: fs: GPF in bd_mount

2016-09-05 Thread Dmitry Vyukov
On Sun, Sep 4, 2016 at 4:29 PM, Al Viro wrote: > On Sun, Sep 04, 2016 at 03:06:06PM +0100, Al Viro wrote: > >> Said that, I'm not sure why mount_pseudo() would be returning any errors; >> rejection should happen in the caller (due to MS_NOUSER in the flags), but >> I don't understand what would tr

Re: fs: GPF in bd_mount

2016-09-04 Thread Al Viro
On Sun, Sep 04, 2016 at 12:43:28PM +0200, Dmitry Vyukov wrote: AFAICS, it's been introduced in commit 3684aa7099e0ab1038a1a1bf717ae60ffc3018d1 Author: Shaohua Li Date: Mon Feb 22 15:27:40 2016 -0700 block-dev: enable writeback cgroup support See if you can reproduce it after the following

Re: fs: GPF in bd_mount

2016-09-04 Thread Al Viro
On Sun, Sep 04, 2016 at 03:06:06PM +0100, Al Viro wrote: > Said that, I'm not sure why mount_pseudo() would be returning any errors; > rejection should happen in the caller (due to MS_NOUSER in the flags), but > I don't understand what would trigger it on mount_pseudo() level... I see what's goin

Re: fs: GPF in bd_mount

2016-09-04 Thread Mateusz Guzik
On Sun, Sep 04, 2016 at 12:43:28PM +0200, Dmitry Vyukov wrote: > Hello, > > The following program triggers GPF in bd_mount: > > > // autogenerated by syzkaller (http://github.com/google/syzkaller) > #include > #include > #include > #include > #include > #include > > int main() > { > int

fs: GPF in bd_mount

2016-09-04 Thread Dmitry Vyukov
Hello, The following program triggers GPF in bd_mount: // autogenerated by syzkaller (http://github.com/google/syzkaller) #include #include #include #include #include #include int main() { int fd; unshare(CLONE_NEWUSER); unshare(CLONE_NEWNS); mkdir("./bus", 0662515705056234013740