The quilt patch titled
Subject: objtool: kmsan: list KMSAN API functions as uaccess-safe
has been removed from the -mm tree. Its filename was
objtool-kmsan-list-kmsan-api-functions-as-uaccess-safe.patch
This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: Alexander Potapenko <glider@xxxxxxxxxx>
Subject: objtool: kmsan: list KMSAN API functions as uaccess-safe
Date: Thu, 15 Sep 2022 17:04:05 +0200
KMSAN inserts API function calls in a lot of places (function entries and
exits, local variables, memory accesses), so they may get called from the
uaccess regions as well.
KMSAN API functions are used to update the metadata (shadow/origin pages)
for kernel memory accesses. The metadata pages for kernel pointers are
also located in the kernel memory, so touching them is not a problem. For
userspace pointers, no metadata is allocated.
If an API function is supposed to read or modify the metadata, it does so
for kernel pointers and ignores userspace pointers. If an API function is
supposed to return a pair of metadata pointers for the instrumentation to
use (like all __msan_metadata_ptr_for_TYPE_SIZE() functions do), it
returns the allocated metadata for kernel pointers and special dummy
buffers residing in the kernel memory for userspace pointers.
As a result, none of KMSAN API functions perform userspace accesses, but
since they might be called from UACCESS regions they use
user_access_save/restore().
Link: https://lkml.kernel.org/r/20220915150417.722975-32-glider@xxxxxxxxxx
Signed-off-by: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Alexei Starovoitov <ast@xxxxxxxxxx>
Cc: Andrey Konovalov <andreyknvl@xxxxxxxxx>
Cc: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Eric Biggers <ebiggers@xxxxxxxxxx>
Cc: Eric Biggers <ebiggers@xxxxxxxxxx>
Cc: Eric Dumazet <edumazet@xxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Cc: Ilya Leoshkevich <iii@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Marco Elver <elver@xxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Michael S. Tsirkin <mst@xxxxxxxxxx>
Cc: Pekka Enberg <penberg@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Petr Mladek <pmladek@xxxxxxxx>
Cc: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx>
Cc: Vegard Nossum <vegard.nossum@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
tools/objtool/check.c | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
--- a/tools/objtool/check.c~objtool-kmsan-list-kmsan-api-functions-as-uaccess-safe
+++ a/tools/objtool/check.c
@@ -1062,6 +1062,26 @@ static const char *uaccess_safe_builtin[
"__sanitizer_cov_trace_cmp4",
"__sanitizer_cov_trace_cmp8",
"__sanitizer_cov_trace_switch",
+ /* KMSAN */
+ "kmsan_copy_to_user",
+ "kmsan_report",
+ "kmsan_unpoison_entry_regs",
+ "kmsan_unpoison_memory",
+ "__msan_chain_origin",
+ "__msan_get_context_state",
+ "__msan_instrument_asm_store",
+ "__msan_metadata_ptr_for_load_1",
+ "__msan_metadata_ptr_for_load_2",
+ "__msan_metadata_ptr_for_load_4",
+ "__msan_metadata_ptr_for_load_8",
+ "__msan_metadata_ptr_for_load_n",
+ "__msan_metadata_ptr_for_store_1",
+ "__msan_metadata_ptr_for_store_2",
+ "__msan_metadata_ptr_for_store_4",
+ "__msan_metadata_ptr_for_store_8",
+ "__msan_metadata_ptr_for_store_n",
+ "__msan_poison_alloca",
+ "__msan_warning",
/* UBSAN */
"ubsan_type_mismatch_common",
"__ubsan_handle_type_mismatch",
_
Patches currently in -mm which might be from glider@xxxxxxxxxx are
