Re: WARNING: at drivers/tty/tty_buffer.c:476 (tty is NULL)

[Peter Hurley <peter@hurleysoftware.com>]

On Tue, 2013-02-12 at 17:41 +1100, Michael Ellerman wrote:
> On Mon, Feb 11, 2013 at 09:53:58PM -0500, Peter Hurley wrote:
> > On Tue, 2013-02-12 at 13:00 +1100, Michael Ellerman wrote:
> > > > Can you reproduce after using the following patch series?
> > > > [PATCH v3 00/23] ldisc fixes
> > > 
> > > What are they against? I tried Linus' tree and linux-next but they
> > > didn't apply cleanly against either.
> > 
> > The series was generated against next-20130204. 13/23 doesn't apply
> > cleanly at next-20130211 because of changes since. Rebases fine
> > though :)
> 
> Should have tried harder against next, git-am is very picky.
> 
> So running next-20130211, 20 runs of trinity followed by ctrl-c, I saw
> the warning 12 times. Back trace is basically always:
> 
> Call Trace:
> [c00000027a1efb20] [c000000000467b74] .flush_to_ldisc+0x244/0x250 (unreliable)
> [c00000027a1efbd0] [c00000000009ea7c] .process_one_work+0x1bc/0x4f0
> [c00000027a1efc70] [c00000000009f2e0] .worker_thread+0x180/0x4b0
> [c00000027a1efd30] [c0000000000a6c3c] .kthread+0xec/0x100
> [c00000027a1efe30] [c000000000009f64] .ret_from_kernel_thread+0x64/0x80
> 
> 
> Running next-20130211 + "ldisc fixes", 20 runs of trinity followed by ctrl-c,
> I saw the warning _0_ times.
> 
> Insert standard comment about testing only proving the presence of bugs not
> their absence :)

Thanks for testing.

Also, as I noted in 00/23:

Changes in v3:

- Because of new changes to the way drivers interact with tty flip
  buffers, this series no longer purports to prevent the flush_to_ldisc()
  warning.

Regards,
Peter Hurley