Re: [PATCH 2/2] mtd: Check add_mtd_device() ret code

[Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>]

Hi Boris,

On Wed, Jan 2, 2019 at 3:37 PM Boris Brezillon <bbrezillon@xxxxxxxxxx> wrote:
> add_mtd_device() can fail. We should always check its return value
> and gracefully handle the failure case. Fix the call sites where this
> not done (in mtdpart.c) and add a __must_check attribute to the
> prototype to avoid this kind of mistakes.
>
> Signed-off-by: Boris Brezillon <bbrezillon@xxxxxxxxxx>
> ---
> No Fixes or Cc-stable tag here, as this seems to have worked just fine
> without checking add_mtd_device() ret code until we started to expose
> MTD devices as NVMEM providers (queued for 4.21).

Oh yes ;-)

https://lore.kernel.org/lkml/87feac02-e955-1897-d4a4-d6d6d1082e45@xxxxxxxxx/t/

Your patch is very similar to mine, so the crash is gone.
However, the warning is still there:

    m25p80 spi0.0: s25sl032p (4096 Kbytes)
    3 fixed-partitions partitions found on MTD device spi0.0
    Creating 3 MTD partitions on "spi0.0":
    0x000000000000-0x000000080000 : "loader"
    0x000000080000-0x000000600000 : "user"
    mtd: partition "user" extends beyond the end of device "spi0.0" --
size truncated to 0x380000
    0x000000600000-0x000004000000 : "flash"
    mtd: partition "flash" is out of reach -- disabled
    ------------[ cut here ]------------
    WARNING: CPU: 0 PID: 1 at drivers/mtd/mtdcore.c:571
add_mtd_device+0x90/0x3b0

Interestingly, only one partition is created, covering the full size of the
device:

    # cat /proc/partitions
    major minor  #blocks  name

      31        0       4096 mtdblock0

While I would expect two partitions, "loader" and truncated "user":

      31        0        512 mtdblock0
      31        1       3584 mtdblock1

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/