Re: [PATCH] kernel/printk: add kmsg SEEK_CUR handling

[Greg KH <gregkh@linuxfoundation.org>]

On Thu, Mar 12, 2020 at 09:35:33PM -0300, Bruno Meneguele wrote:
> Userspace libraries, e.g. glibc's dprintf(), expect the default return value
> for invalid seek situations: -ESPIPE, but when the IO was over /dev/kmsg the
> current state of kernel code was returning the generic case of an -EINVAL.
> Hence, userspace programs were not behaving as expected or documented.
> 
> With this patch we add SEEK_CUR case returning the expected value and also a
> simple mention of it in kernel's documentation for those relying on that for
> guidance.
> 
> Signed-off-by: Bruno Meneguele <bmeneg@redhat.com>
> ---
>  Documentation/ABI/testing/dev-kmsg | 2 ++
>  kernel/printk/printk.c             | 4 ++++
>  2 files changed, 6 insertions(+)

<formletter>

This is not the correct way to submit patches for inclusion in the
stable kernel tree.  Please read:
    https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
for how to do this properly.

</formletter>