On Sun, Oct 30, 2016 at 07:00:36PM +0100, Jann Horn wrote: > On Sun, Oct 30, 2016 at 11:24:27PM +0530, Sudip Mukherjee wrote: > > On Sunday 30 October 2016 09:14 PM, Jann Horn wrote: > > >free_pardevice() is called by parport_unregister_device() and already frees > > >pp->pdev->name, don't try to do it again. > > > > > >This bug causes kernel crashes. > > > > > >I found and verified this with KASAN and some added pr_emerg()s: > > > > > >[ 60.316568] pp_release: pp->pdev->name == ffff88039cb264c0 > > >[ 60.316692] free_pardevice: freeing par_dev->name at ffff88039cb264c0 > > >[ 60.316706] pp_release: kfree(ffff88039cb264c0) > > >[ 60.316714] ========================================================== > > >[ 60.316722] BUG: Double free or freeing an invalid pointer > > >[ 60.316731] Unexpected shadow byte: 0xFB > > >[ 60.316801] Object at ffff88039cb264c0, in cache kmalloc-32 size: 32 > > >[ 60.316813] Allocated: > > >[ 60.316824] PID = 1695 > > >[ 60.316869] Freed: > > >[ 60.316880] PID = 1695 > > >[ 60.316935] ========================================================== > > > > > >CCing Andy Lutomirski because I think this is what broke vmapped stacks > > >for me - after applying this patch, vmapped stacks worked for me. > > >Previously, I got oopses (and lockups) caused by area->pages[0] being > > >0x400000000 in __vunmap(), with area->pages being allocated in the kmalloc > > >area. > > > > I think the above should not be a part of the commit message. > > Ah, yes. > > @maintainers: Feel free to remove that from the commit message. Or should I > resend?
Please resend, never make a maintainer hand-edit a patch changelog :) thanks, greg k-h
