Re: Widespread crashes in next-20180906

["Theodore Y. Ts'o" <tytso@mit.edu>]

On Thu, Sep 06, 2018 at 06:45:15AM -0700, Guenter Roeck wrote:
> Build results:
> 	total: 134 pass: 133 fail: 1
> Failed builds:
> 	sparc32:allmodconfig
> Qemu test results:
> 	total: 311 pass: 76 fail: 235
> Failed builds:
> 	<pretty much everything trying to boot from disk>
> 
> Error message is always something like
> 
> Filesystem requires source device
> VFS: Cannot open root device "hda" or unknown-block(3,0): error -2
> 
> The only variance is the boot device. Logs in full glory are available
> at https://kerneltests.org/builders/, in the "next" column.
> 
> I did not run bisect, but the recent filesystem changes are a definite suspect.

Yes, this is the vm_fault_t changes.  See the other thread on LKML.
The guilty commit was: 83c0adddcc6e: fs: convert return type int to
vm_fault_t

This is the *second* time vm_fault_t patches have broken things.  The
first time it went through the ext4 tree, and I NACK'ed it after
running a 60 second smoke test showed it was broken.  The seocnd time
the problem was supposedly fixed, but it went through the mm tree, and
so I didn't have a chance regression test or stop it...

      		       		  	      	     - Ted