Re: [PATCH v5 04/44] x86: asm: instrument usercopy in get_user() and put_user()

Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> · Mon, 29 Aug 2022 12:24:52 -0700

On Mon, 29 Aug 2022 16:57:31 +0200 Alexander Potapenko <glider@xxxxxxxxxx> wrote:

> On Sat, Aug 27, 2022 at 6:17 AM Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
> >
> > On Fri, 26 Aug 2022 17:07:27 +0200 Alexander Potapenko <glider@xxxxxxxxxx> wrote:
> >
> > > Use hooks from instrumented.h to notify bug detection tools about
> > > usercopy events in variations of get_user() and put_user().
> >
> > And this one blows up x86_64 allmodconfig builds.
> 
> How do I reproduce this?
> I tried running `make mrproper; make allmodconfig; make -j64` (or
> allyesconfig, allnoconfig) on both KMSAN tree
> (https://github.com/google/kmsan/commit/ac3859c02d7f40f59992737d63afcacda0a972ec,
> which is Linux v6.0-rc2 plus the 44 KMSAN patches) and
> linux-mm/mm-stable @ec6624452e36158d0813758d837f7a2263a4109d with
> KMSAN patches applied on top of it.
> All builds were successful.
> 
> I then tried to cherry-pick just the first 4 commits to mm-stable and
> see if allmodconfig works - it resulted in numerous "implicit
> declaration of function ‘instrument_get_user’" errors (quite silly of
> me), but nothing looking like the errors you posted.
> I'll try to build-test every patch in the series after fixing the
> missing declarations, but so far I don't see other problems.
> 
> Could you share the mmotm commit id which resulted in the failures?

I just pushed out a tree which exhibits this with gcc-12.1.1 and with
gcc-11.1.0.  Tag is mm-everything-2022-08-29-19-17.

The problem is introduced by d0d9a44d2210 ("kmsan: add KMSAN runtime core")

make mrproper
make allmodconfig
make init/do_mounts.o

In file included from ./include/linux/kernel.h:22,
                 from ./arch/x86/include/asm/percpu.h:27,
                 from ./arch/x86/include/asm/nospec-branch.h:14,
                 from ./arch/x86/include/asm/paravirt_types.h:40,
                 from ./arch/x86/include/asm/ptrace.h:97,
                 from ./arch/x86/include/asm/math_emu.h:5,
                 from ./arch/x86/include/asm/processor.h:13,
                 from ./arch/x86/include/asm/timex.h:5,
                 from ./include/linux/timex.h:67,
                 from ./include/linux/time32.h:13,
                 from ./include/linux/time.h:60,
                 from ./include/linux/stat.h:19,
                 from ./include/linux/module.h:13,
                 from init/do_mounts.c:2:
./include/linux/page-flags.h: In function ‘page_fixed_fake_head’:
./include/linux/page-flags.h:226:36: error: invalid use of undefined type ‘const struct page’
  226 |             test_bit(PG_head, &page->flags)) {
      |                                    ^~
./include/linux/bitops.h:50:44: note: in definition of macro ‘bitop’
   50 |           __builtin_constant_p((uintptr_t)(addr) != (uintptr_t)NULL) && \
      |                                            ^~~~
./include/linux/page-flags.h:226:13: note: in expansion of macro ‘test_bit’
  226 |             test_bit(PG_head, &page->flags)) {
      |             ^~~~~~~~
...