On Mon, Dec 25, 2023, xingwei lee wrote: > Hello I found a bug in latest upstream 6.7-rc7 titled "KMSAN: > uninit-value in em_ret_far” and maybe is realted with kvm. > > If you fix this issue, please add the following tag to the commit: > Reported-by: xingwei lee <xrivendell7@xxxxxxxxx> > > kernel: mainline 861deac3b092f37b2c5e6871732f3e11486f7082 > kernel config: https://syzkaller.appspot.com/text?tag=KernelConfig&x=4a65fa9f077ead01 > with KMSAN enabled > compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 > run the repro.c for about 3minus and it crashed! > > TITLE: KMSAN: uninit-value in em_ret_far > ===================================================== > BUG: KMSAN: uninit-value in emulator_recalc_and_set_mode > arch/x86/kvm/emulate.c:797 [inline] > BUG: KMSAN: uninit-value in assign_eip_far arch/x86/kvm/emulate.c:833 [inline] > BUG: KMSAN: uninit-value in em_ret_far+0x348/0x350 arch/x86/kvm/emulate.c:2258 > emulator_recalc_and_set_mode arch/x86/kvm/emulate.c:797 [inline] > assign_eip_far arch/x86/kvm/emulate.c:833 [inline] This is a known issue[1]. It's effectively a false positive, even though there is technically uninitialized data in scope. The proposed fix[2] from Julian should resolve this (the patch is on my radar for 6.9). [1] https://lore.kernel.org/all/9362077ac7f24ec684d338543e269e83aee7c897.camel@xxxxxxxxxxxxxxxxxxxxx [2] https://lore.kernel.org/all/20231009092054.556935-1-julian.stecklina@xxxxxxxxxxxxxxxxxxxxx
