[llvm-bugs] [Bug 34038] New: program crashes at movaps, unaligned stack address, -O3
via llvm-bugs
llvm-bugs at lists.llvm.org
Wed Aug 2 17:49:10 PDT 2017
https://bugs.llvm.org/show_bug.cgi?id=34038
Bug ID: 34038
Summary: program crashes at movaps, unaligned stack address,
-O3
Product: libraries
Version: 4.0
Hardware: PC
OS: Linux
Status: NEW
Severity: release blocker
Priority: P
Component: Backend: X86
Assignee: unassignedbugs at nondot.org
Reporter: eric at youngblut.net
CC: llvm-bugs at lists.llvm.org
Created attachment 18898
--> https://bugs.llvm.org/attachment.cgi?id=18898&action=edit
C program for repro
ericy at mrpink:~$ /usr/bin/clang --version
clang version 4.0.0-1ubuntu1 (tags/RELEASE_400/rc1)
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/bin
ericy at mrpink:~$ /usr/bin/clang -O3 movaps_unaligned_crash.c && ./a.out
Segmentation fault
It does not repro with -O2.
You can see that it used the movaps instruction with an unaligned address.
(gdb) disassemble
Dump of assembler code for function main:
0x0000000000400490 <+0>: sub $0x28,%rsp
0x0000000000400494 <+4>: movq $0x0,0x20(%rsp)
0x000000000040049d <+13>: movq $0x0,0x18(%rsp)
0x00000000004004a6 <+22>: mov 0x200b7b(%rip),%rax # 0x601028
<obj>
=> 0x00000000004004ad <+29>: movaps 0x18(%rsp),%xmm0
0x00000000004004b2 <+34>: movaps %xmm0,(%rsp)
0x00000000004004b6 <+38>: mov $0x601028,%edi
0x00000000004004bb <+43>: xor %esi,%esi
0x00000000004004bd <+45>: xor %edx,%edx
0x00000000004004bf <+47>: xor %ecx,%ecx
0x00000000004004c1 <+49>: xor %r8d,%r8d
0x00000000004004c4 <+52>: callq *(%rax)
0x00000000004004c6 <+54>: xor %eax,%eax
0x00000000004004c8 <+56>: add $0x28,%rsp
0x00000000004004cc <+60>: retq
End of assembler dump.
(gdb) p $rsp
$1 = (void *) 0x7fffffffdf50
--
You are receiving this mail because:
You are on the CC list for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-bugs/attachments/20170803/2aecdc03/attachment-0001.html>
More information about the llvm-bugs
mailing list