Hi On Mon, Apr 1, 2013 at 3:53 PM, Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote: > On Mon, Apr 1, 2013 at 10:00 AM, Anatol Pomozov > <anatol.pomozov@xxxxxxxxx> wrote: >> Hi >> >> On Mon, Apr 1, 2013 at 8:16 AM, Linus Torvalds >> <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote: >>> On Mon, Apr 1, 2013 at 4:58 AM, Anatol Pomozov <anatol.pomozov@xxxxxxxxx> wrote: >>>> >>>> To prevent use-after-free we need to hold device inode in loop_set_fd() >>>> and put it later in loop_clr_fd(). >>> >>> Is there something that guarantees that there's only one loop_set_fd() >>> and one paired loop_clr_fd()? >> >> Yes there is such guarantee. >> >> Every time we call loop_set_fd() we check that loop_device->lo_state >> is Lo_unbound and set it to Lo_bound If somebody will try to set_fd >> again it will get EBUSY. And if we try to loop_clr_fd() on unbound >> loop device we'll get ENXIO. >> >> loop_set_fd/loop_clr_fd (and any other loop ioctl) is called under >> loop_device->lo_ctl_mutex. > > Ok, good enough for me, I applied it, and it's commit > c1681bf8a7b1b98edee8b862a42c19c4e53205fd in my tree. > > I assume it should go to stable too, because none of this is new, is > it? Did you check how far back this applies? I assume this goes back > pretty much forever, no? I bisected kernel using test from my commit and it points to 4c823cc3d568277aa6340d8df6981e34f4c4dee5 (appeared in kernel 3.2). But even despite i cannot repro the crash on 3.0-stable, the underlying issue (block_device is not locked) still exists there. So I think patch should go to stable as well. -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html