Control: retitle -1 segmentation fault on any code compiled by tcc with libc6
2.21-4
Cc to the glibc maintainers because the cause of the bug is due to
some change in glibc.
On 2015-12-15 09:35:04 +0100, Vincent Lefevre wrote:
> Code compiled by tcc segfaults:
>
> ypig% cat conftest.c
> int main (void)
> { return 0; }
> ypig% tcc conftest.c -o conftest
> ypig% ./conftest
> zsh: segmentation fault (core dumped) ./conftest
The cause is libc6 2.21. I get this problem with libc6 2.21-4,
but on another machine, after reverting to libc6 2.19-22, this
problem no longer occurs. So, I wonder whether this is a tcc
bug or a glibc one.
In the "objdump -S" output of conftest, I notice the following
difference:
libc6 2.19:
0000000000400430 <_init>:
400430: 48 83 ec 08 sub $0x8,%rsp
400434: 48 8b 05 4d 01 20 00 mov 0x20014d(%rip),%rax #
600588 <_init+0x200158>
[...]
libc6 2.21:
00000000004003f0 <_init>:
4003f0: 48 83 ec 08 sub $0x8,%rsp
4003f4: 48 8b 05 00 00 00 00 mov 0x0(%rip),%rax # 4003fb
<_init+0xb>
The 0x20014d(%rip) has changed to 0x0(%rip).
--
Vincent Lefèvre <vinc...@vinc17.net> - Web: <https://www.vinc17.net/>
100% accessible validated (X)HTML - Blog: <https://www.vinc17.net/blog/>
Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)
