Date: Thu, 01 Dec 2016 02:56:14 +0000 From: bugzilla-noreply@freebsd.org To: freebsd-bugs@FreeBSD.org Subject: [Bug 214972] rtld relies on non-zero _DYNAMIC GOT entry (on !sparc64) Message-ID: <bug-214972-8@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D214972 Bug ID: 214972 Summary: rtld relies on non-zero _DYNAMIC GOT entry (on !sparc64) Product: Base System Version: CURRENT Hardware: Any OS: Any Status: New Severity: Affects Only Me Priority: --- Component: bin Assignee: freebsd-bugs@FreeBSD.org Reporter: emaste@freebsd.org Over a decade ago a binutils import broke sparc64 rtld, and it was fixed in r130661 Quoting from that commit message: The rtld code tested &_DYNAMIC against 0 to see whether rtld itself was built as PIC or not. While the sparc64 MD code did not rely on the preset value of the GOT slot for _DYNAMIC any more due to previous binutils changes, it still used to not be 0, so that this check did work. The new binutils do however initialize this slot with 0. As a consequence, rtld would not properly initialize itself and crash. Fix that by introducing a new macro, RTLD_IS_DYNAMIC, to take the role of this test. For sparc64, it is implemented using the rtld_dynamic() code that was already there. If an architecture does not provide its own implementation, we default to the old check. I have been testing LLD as a linker for FreeBSD, and a recent LLD change (t= heir r288107) started producing a zeroed GOT on amd64. See http://llvm.org/pr312= 21. I don't believe the linker is required to populate the GOT with nonzero val= ues, so we should probably make a change for all architectures akin to r130661 f= or sparc64 . --=20 You are receiving this mail because: You are the assignee for the bug.=
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