[llvm-dev] Hardware ASan Generating Unknown Instruction

Peter Collingbourne via llvm-dev llvm-dev at lists.llvm.org
Mon Jun 22 14:45:03 PDT 2020


Can you file the bug so that we don't lose track of the issue, please?

Peter

On Mon, Jun 22, 2020 at 2:04 PM Derrick McKee <derrick.mckee at gmail.com>
wrote:

> Should I report a new bug, or will the existing review suffice?
>
> On Mon, Jun 22, 2020 at 5:00 PM Peter Collingbourne <peter at pcc.me.uk>
> wrote:
> >
> > Thanks for the confirmation. From the assembly that was sent on the
> other branch of the thread:
> > > .set .L.str, .L.str.hwasan-3458764513820540928
> >
> > -3458764513820540928 = 0xd0 << 56
> > i.e. a "negative" tag.
> >
> > So this appears to be the issue exactly.
> >
> > Peter
> >
> > On Mon, Jun 22, 2020 at 1:55 PM Derrick McKee <derrick.mckee at gmail.com>
> wrote:
> >>
> >> Using lld fixes this issue.
> >>
> >> On Mon, Jun 22, 2020 at 4:51 PM Peter Collingbourne <peter at pcc.me.uk>
> wrote:
> >> >
> >> > I suspect that this is hitting the issue that I mentioned here:
> >> > https://reviews.llvm.org/D65857#1621335
> >> >
> >> > We may need to do what I suggested there and restrict global tag
> entropy on non-Android Linux to 7 bits. You can try working around this
> issue for now by using lld as the linker (-fuse-ld=lld).
> >> >
> >> > Peter
> >> >
> >> > On Mon, Jun 22, 2020 at 1:37 PM Mitch Phillips via llvm-dev <
> llvm-dev at lists.llvm.org> wrote:
> >> >>
> >> >> Hi Derrick,
> >> >>
> >> >> Can you send through `test.c`? What does clang's assembly say
> (`path/to/compiled/clang --target=aarch64-linux-gnu -march=armv8.5-a
> -fsanitize=hwaddress -S test.c; cat test.s`)?
> >> >>
> >> >> - Mitch
> >> >>
> >> >> On Mon, Jun 22, 2020 at 12:04 PM Derrick McKee via llvm-dev <
> llvm-dev at lists.llvm.org> wrote:
> >> >>>
> >> >>> Hi,
> >> >>>
> >> >>> I am trying to execute a simple hello world program compiled like
> so:
> >> >>>
> >> >>> path/to/compiled/clang -o test --target=aarch64-linux-gnu
> >> >>> -march=armv8.5-a -fsanitize=hwaddress
> >> >>> --sysroot=/usr/aarch64-linux-gnu/
> >> >>> -L/usr/lib/gcc/aarch64-linux-gnu/10.1.0/ -g test.c
> >> >>>
> >> >>> However, when I look at the disassembly, there is an unknown
> >> >>> instruction listed at 0x2d51c:
> >> >>>
> >> >>> 000000000002d4c0 main:
> >> >>>    2d4c0: ff c3 00 d1                      sub    sp, sp, #48
> >> >>>    2d4c4: fd 7b 02 a9                      stp    x29, x30, [sp,
> #32]
> >> >>>    2d4c8: fd 83 00 91                      add    x29, sp, #32
> >> >>>    2d4cc: 08 01 00 d0                      adrp    x8, #139264
> >> >>>    2d4d0: 08 49 47 f9                      ldr    x8, [x8, #3728]
> >> >>>    2d4d4: 49 d0 3b d5                      mrs    x9, TPIDR_EL0
> >> >>>    2d4d8: 28 69 68 f8                      ldr    x8, [x9, x8]
> >> >>>    2d4dc: 08 7d 40 b2                      orr    x8, x8,
> #0xffffffff
> >> >>>    2d4e0: 08 05 00 91                      add    x8, x8, #1
> >> >>>    2d4e4: a2 13 00 d1                      sub    x2, x29, #4
> >> >>>    2d4e8: e9 03 08 aa                      mov    x9, x8
> >> >>>    2d4ec: df 64 ff 97                      bl    #-158852
> >> >>> <__hwasan_check_x2_18_short>
> >> >>>    2d4f0: ea 03 1f 2a                      mov    w10, wzr
> >> >>>    2d4f4: aa c3 1f b8                      stur    w10, [x29, #-4]
> >> >>>    2d4f8: a2 23 00 d1                      sub    x2, x29, #8
> >> >>>    2d4fc: e9 03 08 aa                      mov    x9, x8
> >> >>>    2d500: da 64 ff 97                      bl    #-158872
> >> >>> <__hwasan_check_x2_18_short>
> >> >>>    2d504: a0 83 1f b8                      stur    w0, [x29, #-8]
> >> >>>    2d508: e2 43 00 91                      add    x2, sp, #16
> >> >>>    2d50c: e9 03 08 aa                      mov    x9, x8
> >> >>>    2d510: ec 64 ff 97                      bl    #-158800
> >> >>> <__hwasan_check_x2_19_short>
> >> >>>    2d514: e1 0b 00 f9                      str    x1, [sp, #16]
> >> >>>    2d518: 40 00 00 d0                      adrp    x0, #40960
> >> >>>    2d51c: e0 ff e5 b2                      <unknown>
> >> >>>    2d520: 00 40 35 91                      add    x0, x0, #3408
> >> >>>    2d524: ea 0f 00 b9                      str    w10, [sp, #12]
> >> >>>    2d528: c2 64 ff 97                      bl    #-158968
> <printf at plt>
> >> >>>    2d52c: ea 0f 40 b9                      ldr    w10, [sp, #12]
> >> >>>    2d530: e0 0b 00 b9                      str    w0, [sp, #8]
> >> >>>    2d534: e0 03 0a 2a                      mov    w0, w10
> >> >>>    2d538: fd 7b 42 a9                      ldp    x29, x30, [sp,
> #32]
> >> >>>    2d53c: ff c3 00 91                      add    sp, sp, #48
> >> >>>    2d540: c0 03 5f d6                      ret
> >> >>>
> >> >>>
> >> >>> Am I compiling the program incorrectly?  For reference, here's my
> clang version
> >> >>>
> >> >>> # llvm-project/build-10.x/install/bin/clang --version
> >> >>>                                              [1]
> >> >>> clang version 10.0.1 (git at github.com:llvm/llvm-project.git
> >> >>> a634a80615b1e012f1a61aa0cd1e2e67ef77d0bd)
> >> >>> Target: x86_64-unknown-linux-gnu
> >> >>> Thread model: posix
> >> >>>
> >> >>> --
> >> >>> Derrick McKee
> >> >>> Phone: (703) 957-9362
> >> >>> Email: derrick.mckee at gmail.com
> >> >>> _______________________________________________
> >> >>> LLVM Developers mailing list
> >> >>> llvm-dev at lists.llvm.org
> >> >>> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
> >> >>
> >> >> _______________________________________________
> >> >> LLVM Developers mailing list
> >> >> llvm-dev at lists.llvm.org
> >> >> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
> >> >
> >> >
> >> >
> >> > --
> >> > --
> >> > Peter
> >>
> >>
> >>
> >> --
> >> Derrick McKee
> >> Phone: (703) 957-9362
> >> Email: derrick.mckee at gmail.com
> >
> >
> >
> > --
> > --
> > Peter
>
>
>
> --
> Derrick McKee
> Phone: (703) 957-9362
> Email: derrick.mckee at gmail.com
>


-- 
-- 
Peter
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