From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
To: LKML <linux-kernel@vger.kernel.org>,
the arch/x86 maintainers <x86@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
"H. Peter Anvin" <hpa@zytor.com>
Subject: [PATCH v2] x86: disable non-instrumented version of copy_mc when KMSAN is enabled
Date: Sat, 2 Mar 2024 07:52:23 +0900 [thread overview]
Message-ID: <3b7dbd88-0861-4638-b2d2-911c97a4cadf@I-love.SAKURA.ne.jp> (raw)
dump_emit_page() caused a false-positive KMSAN warning, for
memcpy_from_iter_mc() is called via iterate_bvec() by setting "struct
iov_iter"->copy_mc to true.
Fallback to memcpy()/copy_user_generic() when KMSAN is enabled.
Reported-by: syzbot <syzbot+d7521c1e3841ed075a42@syzkaller.appspotmail.com>
Closes: https://syzkaller.appspot.com/bug?extid=d7521c1e3841ed075a42
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Tested-by: syzbot <syzbot+d7521c1e3841ed075a42@syzkaller.appspotmail.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
---
Changes in v2:
Update description.
arch/x86/lib/copy_mc.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/arch/x86/lib/copy_mc.c b/arch/x86/lib/copy_mc.c
index 6e8b7e600def..c6a0b8dbf58d 100644
--- a/arch/x86/lib/copy_mc.c
+++ b/arch/x86/lib/copy_mc.c
@@ -61,9 +61,9 @@ unsigned long copy_mc_enhanced_fast_string(void *dst, const void *src, unsigned
*/
unsigned long __must_check copy_mc_to_kernel(void *dst, const void *src, unsigned len)
{
- if (copy_mc_fragile_enabled)
+ if (!IS_ENABLED(CONFIG_KMSAN) && copy_mc_fragile_enabled)
return copy_mc_fragile(dst, src, len);
- if (static_cpu_has(X86_FEATURE_ERMS))
+ if (!IS_ENABLED(CONFIG_KMSAN) && static_cpu_has(X86_FEATURE_ERMS))
return copy_mc_enhanced_fast_string(dst, src, len);
memcpy(dst, src, len);
return 0;
@@ -74,14 +74,14 @@ unsigned long __must_check copy_mc_to_user(void __user *dst, const void *src, un
{
unsigned long ret;
- if (copy_mc_fragile_enabled) {
+ if (!IS_ENABLED(CONFIG_KMSAN) && copy_mc_fragile_enabled) {
__uaccess_begin();
ret = copy_mc_fragile((__force void *)dst, src, len);
__uaccess_end();
return ret;
}
- if (static_cpu_has(X86_FEATURE_ERMS)) {
+ if (!IS_ENABLED(CONFIG_KMSAN) && static_cpu_has(X86_FEATURE_ERMS)) {
__uaccess_begin();
ret = copy_mc_enhanced_fast_string((__force void *)dst, src, len);
__uaccess_end();
--
2.34.1
next reply other threads:[~2024-03-01 22:52 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-01 22:52 Tetsuo Handa [this message]
2024-03-05 11:31 ` [PATCH v2] x86: disable non-instrumented version of copy_mc when KMSAN is enabled Tetsuo Handa
2024-03-05 16:22 ` Thomas Gleixner
2024-03-05 17:57 ` Linus Torvalds
2024-03-06 22:08 ` Tetsuo Handa
2024-03-07 0:09 ` Linus Torvalds
2024-03-19 12:38 ` Alexander Potapenko
2024-03-06 9:16 ` Ingo Molnar
2024-03-06 10:12 ` Tetsuo Handa
2024-03-05 15:21 ` Dave Hansen
2024-03-05 16:50 ` Thomas Gleixner
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