[llvm-dev] Hardware ASan Generating Unknown Instruction
Derrick McKee via llvm-dev
llvm-dev at lists.llvm.org
Mon Jun 22 14:04:28 PDT 2020
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
>> >>
>> >> _______________________________________________
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>> >
>> >
>> >
>> > --
>> > --
>> > 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
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