On 2018/12/17 19:08, Dmitry Vyukov wrote: > On Mon, Dec 17, 2018 at 8:21 AM Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote: >>> slab_pre_alloc_hook mm/slab.h:423 [inline] >>> slab_alloc mm/slab.c:3365 [inline] >>> kmem_cache_alloc+0x2c4/0x730 mm/slab.c:3539 >>> __d_alloc+0xc8/0xb90 fs/dcache.c:1599 >>> ------------[ cut here ]------------ >>> kernel BUG at fs/inode.c:1566! >>> d_alloc_anon fs/dcache.c:1698 [inline] >>> d_make_root+0x43/0xc0 fs/dcache.c:1885 >>> autofs_fill_super+0x6f1/0x1c30 fs/autofs/inode.c:273 >> >> Huh? BUG is in iput(), AFAICS, so the stack trace is rather misreported. > > Yes, it's a known problem that kernel is generally incapable of > producing parsable crash reports. I think Tetsuo is working on a > solution, but it takes very large amount of discussions and months of > time. The solution, CONFIG_PRINTK_FROM option (which will be renamed to CONFIG_PRINTK_CALLER option tomorrow), just arrived at linux-next-20181218. We can try it... But currently syzbot cannot boot using linux-next-20181218 due to "Kernel panic - not syncing: Can't create rootfs" presumably due to changes merged by "Merge branches 'work.mount', 'work.misc', 'misc.misc' and 'work.iov_iter' into for-next". I think that we need to examine this "Can't create rootfs" problem, for the merge window is approaching...
