[Cluster-devel] [REPORT] kernel BUG at fs/ext4/inode.c:2620 - page_buffers()

[Theodore Ts'o]

On Wed, Feb 23, 2022 at 04:44:07PM -0800, John Hubbard wrote:
> 
> Actually...I can confirm that real customers really are doing *exactly* 
> that! Despite the kernel crashes--because the crashes don't always 
> happen unless you have a large (supercomputer-sized) installation. And 
> even then it is not always root-caused properly.

Interesting.  The syzbot reproducer triggers *reliably* on ext4 using
a 2 CPU qemu kernel running on a laptop, and it doesn't require root,
so it's reasonable that Lee is pushing for a fix --- even if for the
Android O or newer, Seccomp can probably prohibit trap
process_vm_writev(2), but it seems unfortunate if say, someone running
a Docker container could take down the entire host OS.

  	 	   	      	       	      - Ted