Re: [GIT PULL] first round of SCSI updates for the 5.13+ merge window

[Dan Carpenter]

On Tue, Jul 06, 2021 at 03:59:51PM +0200, 'Marco Elver' via syzkaller-bugs wrote:
> On Fri, Jul 02, 2021 at 09:11AM +0100, James Bottomley wrote:
> [...]
> >       scsi: core: Kill DRIVER_SENSE
> [...]
> 
> As of this being merged, most of our syzbot instances are broken with:
> 
> | Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)
> | CPU: 1 PID: 1 Comm: swapper/0 Not tainted 5.13.0-syzkaller #0
> | Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> | Call Trace:
> |  __dump_stack lib/dump_stack.c:79 [inline]
> |  dump_stack_lvl+0x6e/0x91 lib/dump_stack.c:96
> |  panic+0x192/0x4c7 kernel/panic.c:232
> |  mount_block_root+0x268/0x31a init/do_mounts.c:439
> |  mount_root+0x162/0x18d init/do_mounts.c:555
> |  prepare_namespace+0x1ff/0x234 init/do_mounts.c:607
> |  kernel_init_freeable+0x2c4/0x2d6 init/main.c:1604
> |  kernel_init+0x1a/0x1c0 init/main.c:1483
> |  ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
> 
> I've bisected the problem to 464a00c9e0ad ("scsi: core: Kill DRIVER_SENSE"):

Here is one of syzbot reports.

https://groups.google.com/g/syzkaller-bugs/c/6aqmRNRYI7E/m/V7BNerRfDAAJ

If you look at the console output link, init_mount() is failing with
-ENXIO.  It looks the sda drive is not found at all.  It's supposed to
print a list of available partitions but the list is empty.

regards,
dan carpenter