On Sat, Oct 10, 2020 at 01:55:24AM +0000, Alexander Viro wrote:

FWIW, I hadn't pushed that branch out (or merged it into #for-next yet);
for one thing, uml part (mconsole) is simply broken, for another...
IMO ##5--8 are asking for kernel_pread() and if you look at binfmt_elf.c,
you'll see elf_read() being pretty much that.  acct.c, keys and usermode
parts are asking for kernel_pwrite() as well.

I've got stuck looking through the drivers/target stuff - it would've
been another kernel_pwrite() candidate, but it smells like its use of
filp_open() is really asking for trouble, starting with symlink attacks.
Not sure - I'm not familiar with the area, but...

Can you just pull in the minimal fix so that the branch gets fixed
for this merge window?  All the cleanups can come later.