[PATCH v2 2/2] console: Don't start/stop console if stdio device invalid

[Tom Rini]

On Fri, Feb 05, 2021 at 12:50:56PM -0500, Tom Rini wrote:
> On Fri, Feb 05, 2021 at 07:06:54PM +0200, Andy Shevchenko wrote:
> > On Wed, Feb 03, 2021 at 11:50:53AM +0200, Andy Shevchenko wrote:
> > > On Mon, Feb 1, 2021 at 9:29 PM Tom Rini <trini at konsulko.com> wrote:
> > > >
> > > > On Fri, Jan 29, 2021 at 09:50:50AM +0100, Matthias Brugger wrote:
> > > > >
> > > > >
> > > > > On 28/01/2021 16:52, Andy Shevchenko wrote:
> > > > > > On Thu, Jan 28, 2021 at 02:12:40PM +0100, Nicolas Saenz Julienne wrote:
> > > > > >> Don't start/stop an stdio device that might have been already freed.
> > > > > >>
> > > > > >> Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne at suse.de>
> > > > > >> Fixes: 70c2525c0d3c ("IOMUX: Stop dropped consoles")
> > > > > >
> > > > > > ...
> > > > > >
> > > > > >> +  /*
> > > > > >> +   * TODO: This is a workaround to avoid accessing freed memory:
> > > > > >> +   * console_stop() might be called on an stdio_dev that has already been
> > > > > >> +   * de-registered, due to the fact that stdio_deregister_dev()
> > > > > >> +   * doesn't update the global console_devices array.
> > > > > >> +   */
> > > > > >
> > > > > > I see now. I think I have experienced this issue from time to time. I will look
> > > > > > at it. Tom, Simon, please hold on applying these for a while.
> > > > > >
> > > > >
> > > > > Just for the notes, the failing tests hold back Nicolas series to support
> > > > > RPi400/CM4 [1] as it does not run the new tests added successfully. If it takes
> > > > > a long time to fix the test environment, I'd vote to take this series as a
> > > > > stop-gap so that we can support that HW in the next release.
> > > >
> > > > Andy, since you're working on a better solution, do you want more time
> > > > for that or should I pick this series up for now and you can revert it
> > > > as part of your better fix?  Thanks!
> > > 
> > > Sorry for the delayed reply. Give me a couple of days, and if I will
> > > come up without any (good) solution, apply this series.
> > 
> > Okay, as promised, I prepared a branch [1] with new approach, but while I will
> > be busy with other stuff, I would like you to test on real hardware and tell if
> > it helps. At least it passes test cases.
> > 
> > If it works, I would like to get a Tested-by tag and will prepare and submit
> > the formal series.
> > 
> > [1]: https://github.com/andy-shev/u-boot/tree/iomux
> 
> I reliably get:
> 
> ========================================== FAILURES ===========================================
> _____________________________ test_ut[ut_dm_fdt_livetree_writing] _____________________________
> 
> u_boot_console = <u_boot_console_sandbox.ConsoleSandbox object at 0x7fe251aeca90>
> ut_subtest = 'dm fdt_livetree_writing'
> 
>     def test_ut(u_boot_console, ut_subtest):
>         """Execute a "ut" subtest.
> 
>         The subtests are collected in function generate_ut_subtest() from linker
>         generated lists by applying a regular expression to the lines of file
>         u-boot.sym. The list entries are created using the C macro UNIT_TEST().
> 
>         Strict naming conventions have to be followed to match the regular
>         expression. Use UNIT_TEST(foo_test_bar, _flags, foo_test) for a test bar in
>         test suite foo that can be executed via command 'ut foo bar' and is
>         implemented in C function foo_test_bar().
> 
>         Args:
>             u_boot_console (ConsoleBase): U-Boot console
>             ut_subtest (str): test to be executed via command ut, e.g 'foo bar' to
>                 execute command 'ut foo bar'
>         """
> 
>         output = u_boot_console.run_command('ut ' + ut_subtest)
> >       assert output.endswith('Failures: 0')
> E       AssertionError: assert False
> E        +  where False = <built-in method endswith of str object at 0x7fe2516c5da0>('Failures: 0')
> E        +    where <built-in method endswith of str object at 0x7fe2516c5da0> = 'Test: dm_test_fdt_livetree_writing: test-fdt.c\r\r\ntest/dm/test-fdt.c:837, dm_test_fdt_livetree_writing(): FDT_ADDR_...\r\nTest: dm_test_fdt_livetree_writing: test-fdt.c (flat tree)\r\r\nLive tree not active; ignore test\r\r\nFailures: 1'.endswith
> 
> test/py/tests/test_ut.py:43: AssertionError
> ------------------------------------ Captured stdout call -------------------------------------
> => ut dm fdt_livetree_writing
> Test: dm_test_fdt_livetree_writing: test-fdt.c
> test/dm/test-fdt.c:837, dm_test_fdt_livetree_writing(): FDT_ADDR_T_NONE == dev_read_addr(dev): Expected 0xffffffff (-1), got 0x42 (66)
> Test: dm_test_fdt_livetree_writing: test-fdt.c (flat tree)
> Live tree not active; ignore test
> Failures: 1
> =>
> 
> On sandbox.  I'm going to take sandbox out of my testing loop for the
> moment and see what Pi and a few others do.

As expected, the rest of the tests (which did pass in sandbox) also pass
on Pi 3 and a few other platforms I have here.  Didn't test USB, etc,
etc, just pytest.

-- 
Tom
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