linux-kernel - [PATCH v2 4/4] x86: Ignore stack unwinding in KCOV

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <eaf54b8634970b73552dcd38bf9be6ef55238c10.1718092070.git.dvyukov@google.com>
Date: Tue, 11 Jun 2024 09:50:33 +0200
From: Dmitry Vyukov <dvyukov@...gle.com>
To: tglx@...utronix.de, mingo@...hat.com, bp@...en8.de, 
	dave.hansen@...ux.intel.com, x86@...nel.org
Cc: linux-kernel@...r.kernel.org, syzkaller@...glegroups.com, elver@...gle.com, 
	glider@...gle.com, nogikh@...gle.com, tarasmadan@...gle.com, 
	Dmitry Vyukov <dvyukov@...gle.com>
Subject: [PATCH v2 4/4] x86: Ignore stack unwinding in KCOV

Stack unwinding produces large amounts of uninteresting coverage.
It's called from KASAN kmalloc/kfree hooks, fault injection, etc.
It's not particularly useful and is not a function of system call args.
Ignore that code.

Signed-off-by: Dmitry Vyukov <dvyukov@...gle.com>
Reviewed-by: Alexander Potapenko <glider@...gle.com>
Reviewed-by: Marco Elver <elver@...gle.com>
Cc: x86@...nel.org
Cc: linux-kernel@...r.kernel.org
Cc: syzkaller@...glegroups.com
---
 arch/x86/kernel/Makefile | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 20a0dd51700a..cd49ebfae984 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -39,6 +39,14 @@ KMSAN_SANITIZE_sev.o					:= n
 # first second.
 KCOV_INSTRUMENT_head$(BITS).o				:= n
 KCOV_INSTRUMENT_sev.o					:= n
+# These are called from save_stack_trace() on debug paths,
+# and produce large amounts of uninteresting coverage.
+KCOV_INSTRUMENT_stacktrace.o				:= n
+KCOV_INSTRUMENT_dumpstack.o				:= n
+KCOV_INSTRUMENT_dumpstack_$(BITS).o			:= n
+KCOV_INSTRUMENT_unwind_orc.o				:= n
+KCOV_INSTRUMENT_unwind_frame.o				:= n
+KCOV_INSTRUMENT_unwind_guess.o				:= n
 
 CFLAGS_irq.o := -I $(src)/../include/asm/trace
 
-- 
2.45.2.505.gda0bf45e8d-goog