Re: [PATCH] loop: add recursion validation to LOOP_CHANGE_FD

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

On Wed, May 09, 2018 at 10:49:54AM +0200, Dmitry Vyukov wrote:
> Hi Ted,
> 
> Did you follow all instructions (commit, config, compiler, etc)?
> syzbot does not have any special magic, it just executes the described
> steps and then collects the kernel crash output it sees.

No, I didn't.  Unfortunately, I don't have the time to repro it on
exactly the config, commit, compiler.  And debugging tons of Syzkaller
commits is not on my OKR list, and I have lots of P0/P1 bugs and
projects that are competing for my attention.

I tried repro'ing it using the standard compiler, and using -rc4 as a
base.  If it doesn't repro there, using my standard kernel config ---
and it requires root, and in my judgement it's *highly* unlikely to
happen in real life --- then it becomes a P2 or P3 bug, it's not worth
my time to build a kernel using exactly the commit, config, and
compiler that Syzkaller specified.  Someday, you or I or someone else
will build at tool that builds the kernel in a GCE VM, using the
specified config and a compiler, and which minimizes the amount of
human toil needed to do the sort of investigation you seem to want to
dump on upstream developers.

There's a *reason* why many upstream developers have been asking for
improvements in the syzkaller tool to reduce toil.  If it's fair for
you to ask for us to do work, then it's also fair for us to ask you to
do work.  And if the answer is "sorry, I don't have the time; other
things are higher priority", that's a fair answer coming from both
sides.

Regards,

						- Ted