[PATCH 05/13] fs: check FMODE_WRITE in __kernel_write

[Linus Torvalds]

On Mon, Jun 15, 2020 at 5:13 AM Christoph Hellwig <hch at lst.de> wrote:
>
> We still need to check if the fѕ is open write, even for the low-level
> helper.

Is there actually a way to trigger something like this? I'm wondering
if it's worth a WARN_ON_ONCE()?

It doesn't sound sensible to have some kernel functionality try to
write to a file it didn't open for write, and sounds like a kernel bug
if this case were to ever trigger..

                Linus