[v2] x86: disable non-instrumented version of copy_mc when KMSAN is enabled
Commit Message
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(-)
@@ -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();