Since version 4.3, gcc changed its behavior concerning the x86/x86-64 ABI and the direction flag, that is it now assumes that the direction flag is cleared at the entry of a function and it doesn't clear once more if needed. According to LWN article GCC 4.3.0 exposes a kernel bug:
A change to GCC for a recent release coupled with a kernel bug has created a messy situation, with possible security implications. GCC changed some assumptions about x86 processor flags, in accordance with the ABI standard, that can lead to memory corruption for programs built with GCC 4.3.0. No one has come up with a way to exploit the flaw, at least yet, but it clearly is a problem that needs to be addressed.
=> GCC 4.3.0 exposes a kernel bug (via ./)
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- Last Updated: Mar/19/2008
{ 3 comments… read them below or add one }
FreeBSD doesn’t use GCC4.3 for kernel and world.
gcc version 4.2.1 20070719 [FreeBSD] this is the version in FreeBSD 7.0R. So it’s *maybe* a problem for the Linux kernel, while using anything bleeding edge.
At least Fedora developers release application versions after testing and changing them a bit. :)
I have 4.1.2. I updated two days ago but gcc hasn’t changed.
BTW, what happened to the kernel bug ??
When I updated two days ago, kernel was updated to
2.6.24.3-34.fc8
This is quite late after the kernel 2.6.24 was released.
hi,
I have fedora 3 , what shall I do to install gcc4.3 , to work with opanMP.
Thanking you
Tagged as: abi, assumptions, bsd, bug, flags, kernel, Linux, memory corruption, messy situation, security implications, x86