Messages in this thread | | | From | Dmitry Vyukov <> | Date | Tue, 15 Nov 2016 06:30:53 +0100 | Subject | Re: kvm: WARNING in em_jmp_far |
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On Tue, Nov 15, 2016 at 6:24 AM, Nadav Amit <nadav.amit@gmail.com> wrote: > >> On Nov 14, 2016, at 9:06 PM, Dmitry Vyukov <dvyukov@google.com> wrote: >> >> Hello, >> >> The following program triggers WARNING in em_jmp_far: >> https://gist.githubusercontent.com/dvyukov/16bfd3d68fa7d5461101ef74e07796e4/raw/e6d663980681f2c5838ff6cd361cede7d3204838/gistfile1.txt >> >> >> WARNING: CPU: 1 PID: 15748 at arch/x86/kvm/emulate.c:2128 em_jmp_far+0x4a7/0x530 > > I don’t know how to “read” the test, but it seems that this warning > can be triggered if CS base/limit cause a #GP exception when EIP > is loaded. > > I think it safe to remove this warning (which I introduced) as well as > the redundant “return rc” that follows it. The code should handle the > emulation correctly regardless of the warning.
There was also a similar WARNING in em_ret_far: https://groups.google.com/forum/#!msg/syzkaller/o5ZftARBhrs/r1ivQ-HtBgAJ
Please mail a fix and add a test.
Thanks
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