linux-toradex.git/scripts/Makefile.kasan, branch v5.19-rc3 Linux kernel for Apalis and Colibri modules kasan: always respect CONFIG_KASAN_STACK 2021-09-24T23:13:35+00:00 Nathan Chancellor nathan@kernel.org 2021-09-24T22:44:00+00:00 19532869feb9b0a97d17ddc14609d1e53a5b60db Currently, the asan-stack parameter is only passed along if CFLAGS_KASAN_SHADOW is not empty, which requires KASAN_SHADOW_OFFSET to be defined in Kconfig so that the value can be checked. In RISC-V's case, KASAN_SHADOW_OFFSET is not defined in Kconfig, which means that asan-stack does not get disabled with clang even when CONFIG_KASAN_STACK is disabled, resulting in large stack warnings with allmodconfig: drivers/video/fbdev/omap2/omapfb/displays/panel-lgphilips-lb035q02.c:117:12: error: stack frame size (14400) exceeds limit (2048) in function 'lb035q02_connect' [-Werror,-Wframe-larger-than] static int lb035q02_connect(struct omap_dss_device *dssdev) ^ 1 error generated. Ensure that the value of CONFIG_KASAN_STACK is always passed along to the compiler so that these warnings do not happen when CONFIG_KASAN_STACK is disabled. Link: https://github.com/ClangBuiltLinux/linux/issues/1453 References: 6baec880d7a5 ("kasan: turn off asan-stack for clang-8 and earlier") Link: https://lkml.kernel.org/r/20210922205525.570068-1-nathan@kernel.org Signed-off-by: Nathan Chancellor <nathan@kernel.org> Reviewed-by: Marco Elver <elver@google.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
Currently, the asan-stack parameter is only passed along if
CFLAGS_KASAN_SHADOW is not empty, which requires KASAN_SHADOW_OFFSET to
be defined in Kconfig so that the value can be checked.  In RISC-V's
case, KASAN_SHADOW_OFFSET is not defined in Kconfig, which means that
asan-stack does not get disabled with clang even when CONFIG_KASAN_STACK
is disabled, resulting in large stack warnings with allmodconfig:

  drivers/video/fbdev/omap2/omapfb/displays/panel-lgphilips-lb035q02.c:117:12: error: stack frame size (14400) exceeds limit (2048) in function 'lb035q02_connect' [-Werror,-Wframe-larger-than]
  static int lb035q02_connect(struct omap_dss_device *dssdev)
             ^
  1 error generated.

Ensure that the value of CONFIG_KASAN_STACK is always passed along to
the compiler so that these warnings do not happen when
CONFIG_KASAN_STACK is disabled.

Link: https://github.com/ClangBuiltLinux/linux/issues/1453
References: 6baec880d7a5 ("kasan: turn off asan-stack for clang-8 and earlier")
Link: https://lkml.kernel.org/r/20210922205525.570068-1-nathan@kernel.org
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
kasan: arm64: support specialized outlined tag mismatch checks 2021-05-26T22:31:26+00:00 Peter Collingbourne pcc@google.com 2021-05-26T17:49:27+00:00 1cbdf60bd1b74e397d48aa877367cfc621f45ffe By using outlined checks we can achieve a significant code size improvement by moving the tag-based ASAN checks into separate functions. Unlike the existing CONFIG_KASAN_OUTLINE mode these functions have a custom calling convention that preserves most registers and is specialized to the register containing the address and the type of access, and as a result we can eliminate the code size and performance overhead of a standard calling convention such as AAPCS for these functions. This change depends on a separate series of changes to Clang [1] to support outlined checks in the kernel, although the change works fine without them (we just don't get outlined checks). This is because the flag -mllvm -hwasan-inline-all-checks=0 has no effect until the Clang changes land. The flag was introduced in the Clang 9.0 timeframe as part of the support for outlined checks in userspace and because our minimum Clang version is 10.0 we can pass it unconditionally. Outlined checks require a new runtime function with a custom calling convention. Add this function to arch/arm64/lib. I measured the code size of defconfig + tag-based KASAN, as well as boot time (i.e. time to init launch) on a DragonBoard 845c with an Android arm64 GKI kernel. The results are below: code size boot time CONFIG_KASAN_INLINE=y before 92824064 6.18s CONFIG_KASAN_INLINE=y after 38822400 6.65s CONFIG_KASAN_OUTLINE=y 39215616 11.48s We can see straight away that specialized outlined checks beat the existing CONFIG_KASAN_OUTLINE=y on both code size and boot time for tag-based ASAN. As for the comparison between CONFIG_KASAN_INLINE=y before and after we saw similar performance numbers in userspace [2] and decided that since the performance overhead is minimal compared to the overhead of tag-based ASAN itself as well as compared to the code size improvements we would just replace the inlined checks with the specialized outlined checks without the option to select between them, and that is what I have implemented in this patch. Signed-off-by: Peter Collingbourne <pcc@google.com> Acked-by: Andrey Konovalov <andreyknvl@gmail.com> Reviewed-by: Mark Rutland <mark.rutland@arm.com> Tested-by: Mark Rutland <mark.rutland@arm.com> Link: https://linux-review.googlesource.com/id/I1a30036c70ab3c3ee78d75ed9b87ef7cdc3fdb76 Link: [1] https://reviews.llvm.org/D90426 Link: [2] https://reviews.llvm.org/D56954 Link: https://lore.kernel.org/r/20210526174927.2477847-3-pcc@google.com Signed-off-by: Will Deacon <will@kernel.org> 
By using outlined checks we can achieve a significant code size
improvement by moving the tag-based ASAN checks into separate
functions. Unlike the existing CONFIG_KASAN_OUTLINE mode these
functions have a custom calling convention that preserves most
registers and is specialized to the register containing the address
and the type of access, and as a result we can eliminate the code
size and performance overhead of a standard calling convention such
as AAPCS for these functions.

This change depends on a separate series of changes to Clang [1] to
support outlined checks in the kernel, although the change works fine
without them (we just don't get outlined checks). This is because the
flag -mllvm -hwasan-inline-all-checks=0 has no effect until the Clang
changes land. The flag was introduced in the Clang 9.0 timeframe as
part of the support for outlined checks in userspace and because our
minimum Clang version is 10.0 we can pass it unconditionally.

Outlined checks require a new runtime function with a custom calling
convention. Add this function to arch/arm64/lib.

I measured the code size of defconfig + tag-based KASAN, as well
as boot time (i.e. time to init launch) on a DragonBoard 845c with
an Android arm64 GKI kernel. The results are below:

                               code size    boot time
CONFIG_KASAN_INLINE=y before    92824064      6.18s
CONFIG_KASAN_INLINE=y after     38822400      6.65s
CONFIG_KASAN_OUTLINE=y          39215616     11.48s

We can see straight away that specialized outlined checks beat the
existing CONFIG_KASAN_OUTLINE=y on both code size and boot time
for tag-based ASAN.

As for the comparison between CONFIG_KASAN_INLINE=y before and after
we saw similar performance numbers in userspace [2] and decided
that since the performance overhead is minimal compared to the
overhead of tag-based ASAN itself as well as compared to the code
size improvements we would just replace the inlined checks with the
specialized outlined checks without the option to select between them,
and that is what I have implemented in this patch.

Signed-off-by: Peter Collingbourne <pcc@google.com>
Acked-by: Andrey Konovalov <andreyknvl@gmail.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Link: https://linux-review.googlesource.com/id/I1a30036c70ab3c3ee78d75ed9b87ef7cdc3fdb76
Link: [1] https://reviews.llvm.org/D90426
Link: [2] https://reviews.llvm.org/D56954
Link: https://lore.kernel.org/r/20210526174927.2477847-3-pcc@google.com
Signed-off-by: Will Deacon <will@kernel.org>
kasan: remove redundant config option 2021-04-16T23:10:36+00:00 Walter Wu walter-zh.wu@mediatek.com 2021-04-16T22:46:00+00:00 02c587733c8161355a43e6e110c2e29bd0acff72 CONFIG_KASAN_STACK and CONFIG_KASAN_STACK_ENABLE both enable KASAN stack instrumentation, but we should only need one config, so that we remove CONFIG_KASAN_STACK_ENABLE and make CONFIG_KASAN_STACK workable. see [1]. When enable KASAN stack instrumentation, then for gcc we could do no prompt and default value y, and for clang prompt and default value n. This patch fixes the following compilation warning: include/linux/kasan.h:333:30: warning: 'CONFIG_KASAN_STACK' is not defined, evaluates to 0 [-Wundef] [akpm@linux-foundation.org: fix merge snafu] Link: https://bugzilla.kernel.org/show_bug.cgi?id=210221 [1] Link: https://lkml.kernel.org/r/20210226012531.29231-1-walter-zh.wu@mediatek.com Fixes: d9b571c885a8 ("kasan: fix KASAN_STACK dependency for HW_TAGS") Signed-off-by: Walter Wu <walter-zh.wu@mediatek.com> Suggested-by: Dmitry Vyukov <dvyukov@google.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Andrey Konovalov <andreyknvl@google.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
CONFIG_KASAN_STACK and CONFIG_KASAN_STACK_ENABLE both enable KASAN stack
instrumentation, but we should only need one config, so that we remove
CONFIG_KASAN_STACK_ENABLE and make CONFIG_KASAN_STACK workable.  see [1].

When enable KASAN stack instrumentation, then for gcc we could do no
prompt and default value y, and for clang prompt and default value n.

This patch fixes the following compilation warning:

  include/linux/kasan.h:333:30: warning: 'CONFIG_KASAN_STACK' is not defined, evaluates to 0 [-Wundef]

[akpm@linux-foundation.org: fix merge snafu]

Link: https://bugzilla.kernel.org/show_bug.cgi?id=210221 [1]
Link: https://lkml.kernel.org/r/20210226012531.29231-1-walter-zh.wu@mediatek.com
Fixes: d9b571c885a8 ("kasan: fix KASAN_STACK dependency for HW_TAGS")
Signed-off-by: Walter Wu <walter-zh.wu@mediatek.com>
Suggested-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
kasan: fix hwasan build for gcc 2021-04-16T23:10:36+00:00 Arnd Bergmann arnd@arndb.de 2021-04-16T22:45:57+00:00 5c595ac4c776c44b5c59de22ab43b3fe256d9fbb gcc-11 adds support for -fsanitize=kernel-hwaddress, so it becomes possible to enable CONFIG_KASAN_SW_TAGS. Unfortunately this fails to build at the moment, because the corresponding command line arguments use llvm specific syntax. Change it to use the cc-param macro instead, which works on both clang and gcc. [elver@google.com: fixup for "kasan: fix hwasan build for gcc"] Link: https://lkml.kernel.org/r/YHQZVfVVLE/LDK2v@elver.google.com Link: https://lkml.kernel.org/r/20210323124112.1229772-1-arnd@kernel.org Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Marco Elver <elver@google.com> Reviewed-by: Marco Elver <elver@google.com> Acked-by: Andrey Konovalov <andreyknvl@gmail.com> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Michal Marek <michal.lkml@markovi.net> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
gcc-11 adds support for -fsanitize=kernel-hwaddress, so it becomes
possible to enable CONFIG_KASAN_SW_TAGS.

Unfortunately this fails to build at the moment, because the
corresponding command line arguments use llvm specific syntax.

Change it to use the cc-param macro instead, which works on both clang
and gcc.

[elver@google.com: fixup for "kasan: fix hwasan build for gcc"]
  Link: https://lkml.kernel.org/r/YHQZVfVVLE/LDK2v@elver.google.com

Link: https://lkml.kernel.org/r/20210323124112.1229772-1-arnd@kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Marco Elver <elver@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Acked-by: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Michal Marek <michal.lkml@markovi.net>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
kbuild: move CFLAGS_{KASAN,UBSAN,KCSAN} exports to relevant Makefiles 2020-09-24T15:36:50+00:00 Masahiro Yamada masahiroy@kernel.org 2020-09-10T13:44:29+00:00 bb2732112bc52bed7b20b9fc59d7246e4e7ce5ed Move CFLAGS_KASAN*, CFLAGS_UBSAN, CFLAGS_KCSAN to Makefile.kasan, Makefile.ubsan, Makefile.kcsan, respectively. This commit also avoids the same -fsanitize=* flags being added to CFLAGS_UBSAN multiple times. Prior to this commit, the ubsan flags were appended by the '+=' operator, without any initialization. Some build targets such as 'make bindeb-pkg' recurses to the top Makefile, and ended up with adding the same flags to CFLAGS_UBSAN twice. Clear CFLAGS_UBSAN with ':=' to make it a simply expanded variable. This is better than a recursively expanded variable, which evaluates $(call cc-option, ...) multiple times before Kbuild starts descending to subdirectories. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Marco Elver <elver@google.com> 
Move CFLAGS_KASAN*, CFLAGS_UBSAN, CFLAGS_KCSAN to Makefile.kasan,
Makefile.ubsan, Makefile.kcsan, respectively.

This commit also avoids the same -fsanitize=* flags being added to
CFLAGS_UBSAN multiple times.

Prior to this commit, the ubsan flags were appended by the '+='
operator, without any initialization. Some build targets such as
'make bindeb-pkg' recurses to the top Makefile, and ended up with
adding the same flags to CFLAGS_UBSAN twice.

Clear CFLAGS_UBSAN with ':=' to make it a simply expanded variable.
This is better than a recursively expanded variable, which evaluates
$(call cc-option, ...) multiple times before Kbuild starts descending
to subdirectories.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Marco Elver <elver@google.com>
kbuild: remove redundant CONFIG_KASAN check from scripts/Makefile.kasan 2020-09-24T15:36:49+00:00 Masahiro Yamada masahiroy@kernel.org 2020-09-10T13:44:28+00:00 9909b7681222299dcb6f3b0613c30a65498b6c72 Since commit e0fe0bbe57b8 ("kbuild: include scripts/Makefile.* only when relevant CONFIG is enabled"), this file is included only when CONFIG_KASAN=y. This ifdef is redundant. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Marco Elver <elver@google.com> 
Since commit e0fe0bbe57b8 ("kbuild: include scripts/Makefile.* only
when relevant CONFIG is enabled"), this file is included only when
CONFIG_KASAN=y.

This ifdef is redundant.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Marco Elver <elver@google.com>
kasan: allow enabling stack tagging for tag-based mode 2020-08-07T18:33:28+00:00 Andrey Konovalov andreyknvl@google.com 2020-08-07T06:25:08+00:00 cae9dc35ed9ff82a99754e51d57ff6c332e1f7e4 Use CONFIG_KASAN_STACK to enable stack tagging. Note, that HWASAN short granules [1] are disabled. Supporting those will require more kernel changes. [1] https://clang.llvm.org/docs/HardwareAssistedAddressSanitizerDesign.html Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Elena Petrova <lenaptr@google.com> Cc: Marco Elver <elver@google.com> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Walter Wu <walter-zh.wu@mediatek.com> Cc: Ard Biesheuvel <ardb@kernel.org> Link: http://lkml.kernel.org/r/e7febb907b539c3730780df587ce0b38dc558c3d.1596199677.git.andreyknvl@google.com Link: http://lkml.kernel.org/r/99f7d90a4237431bf5988599fb41358e92876eb0.1596544734.git.andreyknvl@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
Use CONFIG_KASAN_STACK to enable stack tagging.

Note, that HWASAN short granules [1] are disabled. Supporting those will
require more kernel changes.

[1] https://clang.llvm.org/docs/HardwareAssistedAddressSanitizerDesign.html

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Elena Petrova <lenaptr@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Walter Wu <walter-zh.wu@mediatek.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Link: http://lkml.kernel.org/r/e7febb907b539c3730780df587ce0b38dc558c3d.1596199677.git.andreyknvl@google.com
Link: http://lkml.kernel.org/r/99f7d90a4237431bf5988599fb41358e92876eb0.1596544734.git.andreyknvl@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
kasan/arm64: fix CONFIG_KASAN_SW_TAGS && KASAN_INLINE 2019-08-15T12:24:04+00:00 Mark Rutland mark.rutland@arm.com 2019-08-14T14:31:57+00:00 34b5560db40d2941cfbe82eca1641353d5aed1a9 The generic Makefile.kasan propagates CONFIG_KASAN_SHADOW_OFFSET into KASAN_SHADOW_OFFSET, but only does so for CONFIG_KASAN_GENERIC. Since commit: 6bd1d0be0e97936d ("arm64: kasan: Switch to using KASAN_SHADOW_OFFSET") ... arm64 defines CONFIG_KASAN_SHADOW_OFFSET in Kconfig rather than defining KASAN_SHADOW_OFFSET in a Makefile. Thus, if CONFIG_KASAN_SW_TAGS && KASAN_INLINE are selected, we get build time splats due to KASAN_SHADOW_OFFSET not being set: | [mark@lakrids:~/src/linux]% usellvm 8.0.1 usekorg 8.1.0 make ARCH=arm64 CROSS_COMPILE=aarch64-linux- CC=clang | scripts/kconfig/conf --syncconfig Kconfig | CC scripts/mod/empty.o | clang (LLVM option parsing): for the -hwasan-mapping-offset option: '' value invalid for uint argument! | scripts/Makefile.build:273: recipe for target 'scripts/mod/empty.o' failed | make[1]: *** [scripts/mod/empty.o] Error 1 | Makefile:1123: recipe for target 'prepare0' failed | make: *** [prepare0] Error 2 Let's fix this by always propagating CONFIG_KASAN_SHADOW_OFFSET into KASAN_SHADOW_OFFSET if CONFIG_KASAN is selected, moving the existing common definition of +CFLAGS_KASAN_NOSANITIZE to the top of Makefile.kasan. Cc: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Tested-by Steve Capper <steve.capper@arm.com> Signed-off-by: Will Deacon <will@kernel.org> 
The generic Makefile.kasan propagates CONFIG_KASAN_SHADOW_OFFSET into
KASAN_SHADOW_OFFSET, but only does so for CONFIG_KASAN_GENERIC.

Since commit:

  6bd1d0be0e97936d ("arm64: kasan: Switch to using KASAN_SHADOW_OFFSET")

... arm64 defines CONFIG_KASAN_SHADOW_OFFSET in Kconfig rather than
defining KASAN_SHADOW_OFFSET in a Makefile. Thus, if
CONFIG_KASAN_SW_TAGS && KASAN_INLINE are selected, we get build time
splats due to KASAN_SHADOW_OFFSET not being set:

| [mark@lakrids:~/src/linux]% usellvm 8.0.1 usekorg 8.1.0  make ARCH=arm64 CROSS_COMPILE=aarch64-linux- CC=clang
| scripts/kconfig/conf  --syncconfig Kconfig
|   CC      scripts/mod/empty.o
| clang (LLVM option parsing): for the -hwasan-mapping-offset option: '' value invalid for uint argument!
| scripts/Makefile.build:273: recipe for target 'scripts/mod/empty.o' failed
| make[1]: *** [scripts/mod/empty.o] Error 1
| Makefile:1123: recipe for target 'prepare0' failed
| make: *** [prepare0] Error 2

Let's fix this by always propagating CONFIG_KASAN_SHADOW_OFFSET into
KASAN_SHADOW_OFFSET if CONFIG_KASAN is selected, moving the existing
common definition of +CFLAGS_KASAN_NOSANITIZE to the top of
Makefile.kasan.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Tested-by Steve Capper <steve.capper@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
kasan: remove use after scope bugs detection. 2019-03-06T05:07:13+00:00 Andrey Ryabinin aryabinin@virtuozzo.com 2019-03-05T23:41:20+00:00 7771bdbbfd3d6f204631b6fd9e1bbc30cd15918e Use after scope bugs detector seems to be almost entirely useless for the linux kernel. It exists over two years, but I've seen only one valid bug so far [1]. And the bug was fixed before it has been reported. There were some other use-after-scope reports, but they were false-positives due to different reasons like incompatibility with structleak plugin. This feature significantly increases stack usage, especially with GCC < 9 version, and causes a 32K stack overflow. It probably adds performance penalty too. Given all that, let's remove use-after-scope detector entirely. While preparing this patch I've noticed that we mistakenly enable use-after-scope detection for clang compiler regardless of CONFIG_KASAN_EXTRA setting. This is also fixed now. [1] http://lkml.kernel.org/r/<20171129052106.rhgbjhhis53hkgfn@wfg-t540p.sh.intel.com> Link: http://lkml.kernel.org/r/20190111185842.13978-1-aryabinin@virtuozzo.com Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Acked-by: Will Deacon <will.deacon@arm.com> [arm64] Cc: Qian Cai <cai@lca.pw> Cc: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
Use after scope bugs detector seems to be almost entirely useless for
the linux kernel.  It exists over two years, but I've seen only one
valid bug so far [1].  And the bug was fixed before it has been
reported.  There were some other use-after-scope reports, but they were
false-positives due to different reasons like incompatibility with
structleak plugin.

This feature significantly increases stack usage, especially with GCC <
9 version, and causes a 32K stack overflow.  It probably adds
performance penalty too.

Given all that, let's remove use-after-scope detector entirely.

While preparing this patch I've noticed that we mistakenly enable
use-after-scope detection for clang compiler regardless of
CONFIG_KASAN_EXTRA setting.  This is also fixed now.

[1] http://lkml.kernel.org/r/<20171129052106.rhgbjhhis53hkgfn@wfg-t540p.sh.intel.com>

Link: http://lkml.kernel.org/r/20190111185842.13978-1-aryabinin@virtuozzo.com
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Acked-by: Will Deacon <will.deacon@arm.com>		[arm64]
Cc: Qian Cai <cai@lca.pw>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
kasan: turn off asan-stack for clang-8 and earlier 2019-03-01T17:02:33+00:00 Arnd Bergmann arnd@arndb.de 2019-03-01T00:21:58+00:00 6baec880d7a53cbc2841123e56ee31e830df9b49 Building an arm64 allmodconfig kernel with clang results in over 140 warnings about overly large stack frames, the worst ones being: drivers/gpu/drm/panel/panel-sitronix-st7789v.c:196:12: error: stack frame size of 20224 bytes in function 'st7789v_prepare' drivers/video/fbdev/omap2/omapfb/displays/panel-tpo-td028ttec1.c:196:12: error: stack frame size of 13120 bytes in function 'td028ttec1_panel_enable' drivers/usb/host/max3421-hcd.c:1395:1: error: stack frame size of 10048 bytes in function 'max3421_spi_thread' drivers/net/wan/slic_ds26522.c:209:12: error: stack frame size of 9664 bytes in function 'slic_ds26522_probe' drivers/crypto/ccp/ccp-ops.c:2434:5: error: stack frame size of 8832 bytes in function 'ccp_run_cmd' drivers/media/dvb-frontends/stv0367.c:1005:12: error: stack frame size of 7840 bytes in function 'stv0367ter_algo' None of these happen with gcc today, and almost all of these are the result of a single known issue in llvm. Hopefully it will eventually get fixed with the clang-9 release. In the meantime, the best idea I have is to turn off asan-stack for clang-8 and earlier, so we can produce a kernel that is safe to run. I have posted three patches that address the frame overflow warnings that are not addressed by turning off asan-stack, so in combination with this change, we get much closer to a clean allmodconfig build, which in turn is necessary to do meaningful build regression testing. It is still possible to turn on the CONFIG_ASAN_STACK option on all versions of clang, and it's always enabled for gcc, but when CONFIG_COMPILE_TEST is set, the option remains invisible, so allmodconfig and randconfig builds (which are normally done with a forced CONFIG_COMPILE_TEST) will still result in a mostly clean build. Link: http://lkml.kernel.org/r/20190222222950.3997333-1-arnd@arndb.de Link: https://bugs.llvm.org/show_bug.cgi?id=38809 Signed-off-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Qian Cai <cai@lca.pw> Reviewed-by: Mark Brown <broonie@kernel.org> Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Kostya Serebryany <kcc@google.com> Cc: Andrey Konovalov <andreyknvl@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
Building an arm64 allmodconfig kernel with clang results in over 140
warnings about overly large stack frames, the worst ones being:

  drivers/gpu/drm/panel/panel-sitronix-st7789v.c:196:12: error: stack frame size of 20224 bytes in function 'st7789v_prepare'
  drivers/video/fbdev/omap2/omapfb/displays/panel-tpo-td028ttec1.c:196:12: error: stack frame size of 13120 bytes in function 'td028ttec1_panel_enable'
  drivers/usb/host/max3421-hcd.c:1395:1: error: stack frame size of 10048 bytes in function 'max3421_spi_thread'
  drivers/net/wan/slic_ds26522.c:209:12: error: stack frame size of 9664 bytes in function 'slic_ds26522_probe'
  drivers/crypto/ccp/ccp-ops.c:2434:5: error: stack frame size of 8832 bytes in function 'ccp_run_cmd'
  drivers/media/dvb-frontends/stv0367.c:1005:12: error: stack frame size of 7840 bytes in function 'stv0367ter_algo'

None of these happen with gcc today, and almost all of these are the
result of a single known issue in llvm.  Hopefully it will eventually
get fixed with the clang-9 release.

In the meantime, the best idea I have is to turn off asan-stack for
clang-8 and earlier, so we can produce a kernel that is safe to run.

I have posted three patches that address the frame overflow warnings
that are not addressed by turning off asan-stack, so in combination with
this change, we get much closer to a clean allmodconfig build, which in
turn is necessary to do meaningful build regression testing.

It is still possible to turn on the CONFIG_ASAN_STACK option on all
versions of clang, and it's always enabled for gcc, but when
CONFIG_COMPILE_TEST is set, the option remains invisible, so
allmodconfig and randconfig builds (which are normally done with a
forced CONFIG_COMPILE_TEST) will still result in a mostly clean build.

Link: http://lkml.kernel.org/r/20190222222950.3997333-1-arnd@arndb.de
Link: https://bugs.llvm.org/show_bug.cgi?id=38809
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Qian Cai <cai@lca.pw>
Reviewed-by: Mark Brown <broonie@kernel.org>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Kostya Serebryany <kcc@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>