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| author | Andrey Konovalov <andreyknvl@google.com> | 2022-05-23 16:51:51 +0200 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2022-06-23 15:57:29 +0100 |
| commit | 802b91118d11227b527153849ea761b280691373 (patch) | |
| tree | 18833ea1e3dfb8637e430dd0f52d6f5b9d9d1379 | |
| parent | a111daf0c53ae91e71fd2bfe7497862d14132e3e (diff) | |
| download | linux-802b91118d11227b527153849ea761b280691373.tar.gz linux-802b91118d11227b527153849ea761b280691373.tar.bz2 linux-802b91118d11227b527153849ea761b280691373.zip | |
arm64: kasan: do not instrument stacktrace.c
Disable KASAN instrumentation of arch/arm64/kernel/stacktrace.c.
This speeds up Generic KASAN by 5-20%.
As a side-effect, KASAN is now unable to detect bugs in the stack trace
collection code. This is taken as an acceptable downside.
Also replace READ_ONCE_NOCHECK() with READ_ONCE() in stacktrace.c.
As the file is now not instrumented, there is no need to use the
NOCHECK version of READ_ONCE().
Suggested-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Link: https://lore.kernel.org/r/c4c944a2a905e949760fbeb29258185087171708.1653317461.git.andreyknvl@google.com
Signed-off-by: Will Deacon <will@kernel.org>
| -rw-r--r-- | arch/arm64/kernel/Makefile | 5 | ||||
| -rw-r--r-- | arch/arm64/kernel/stacktrace.c | 4 |
2 files changed, 7 insertions, 2 deletions
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile index fa7981d0d917..7075a9c6a4a6 100644 --- a/arch/arm64/kernel/Makefile +++ b/arch/arm64/kernel/Makefile @@ -14,6 +14,11 @@ CFLAGS_REMOVE_return_address.o = $(CC_FLAGS_FTRACE) CFLAGS_REMOVE_syscall.o = -fstack-protector -fstack-protector-strong CFLAGS_syscall.o += -fno-stack-protector +# When KASAN is enabled, a stack trace is recorded for every alloc/free, which +# can significantly impact performance. Avoid instrumenting the stack trace +# collection code to minimize this impact. +KASAN_SANITIZE_stacktrace.o := n + # It's not safe to invoke KCOV when portions of the kernel environment aren't # available or are out-of-sync with HW state. Since `noinstr` doesn't always # inhibit KCOV instrumentation, disable it for the entire compilation unit. diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c index 0467cb79f080..c246e8d9f95b 100644 --- a/arch/arm64/kernel/stacktrace.c +++ b/arch/arm64/kernel/stacktrace.c @@ -124,8 +124,8 @@ static int notrace unwind_next(struct task_struct *tsk, * Record this frame record's values and location. The prev_fp and * prev_type are only meaningful to the next unwind_next() invocation. */ - state->fp = READ_ONCE_NOCHECK(*(unsigned long *)(fp)); - state->pc = READ_ONCE_NOCHECK(*(unsigned long *)(fp + 8)); + state->fp = READ_ONCE(*(unsigned long *)(fp)); + state->pc = READ_ONCE(*(unsigned long *)(fp + 8)); state->prev_fp = fp; state->prev_type = info.type; |