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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Tobias Klauser <tklauser@distanz.ch>,
        Dmitry Vyukov <dvyukov@google.com>,
        Palmer Dabbelt <palmerdabbelt@google.com>
Subject: [PATCH 5.10 584/663] riscv: Disable KSAN_SANITIZE for vDSO
Date:   Mon,  1 Mar 2021 17:13:52 +0100
Message-Id: <20210301161210.757389079@linuxfoundation.org>
In-Reply-To: <20210301161141.760350206@linuxfoundation.org>
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From: Tobias Klauser <tklauser@distanz.ch>

commit f3d60f2a25e4417e1676161fe42115de3e3f98a2 upstream.

We use the generic C VDSO implementations of a handful of clock-related
functions.  When kasan is enabled this results in asan stub calls that
are unlikely to be resolved by userspace, this just disables KASAN
when building the VDSO.

Verified the fix on a kernel with KASAN enabled using vDSO selftests.

Link: https://lore.kernel.org/lkml/CACT4Y+ZNJBnkKHXUf=tm_yuowvZvHwN=0rmJ=7J+xFd+9r_6pQ@mail.gmail.com/
Tested-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Tested-by: Dmitry Vyukov <dvyukov@google.com>
[Palmer: commit text]
Fixes: ad5d1122b82f ("riscv: use vDSO common flow to reduce the latency of the time-related functions")
Cc: stable@vger.kernel.org
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/riscv/kernel/vdso/Makefile |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/arch/riscv/kernel/vdso/Makefile
+++ b/arch/riscv/kernel/vdso/Makefile
@@ -32,9 +32,10 @@ CPPFLAGS_vdso.lds += -P -C -U$(ARCH)
 # Disable -pg to prevent insert call site
 CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os
 
-# Disable gcov profiling for VDSO code
+# Disable profiling and instrumentation for VDSO code
 GCOV_PROFILE := n
 KCOV_INSTRUMENT := n
+KASAN_SANITIZE := n
 
 # Force dependency
 $(obj)/vdso.o: $(obj)/vdso.so