Messages in this thread | | | Date | Mon, 22 Aug 2011 18:18:15 -0700 | From | "H. Peter Anvin" <> | Subject | Re: [uml-devel] SYSCALL, ptrace and syscall restart breakages (Re: [RFC] weird crap with vdso on uml/i386) |
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On 08/22/2011 06:16 PM, Andrew Lutomirski wrote: > > I suspect that very few things care whether syscall arguments get > clobbered. The only way it would matter is if gcc reuses the argument > in the ecx slot after an inlined syscall later in the same function. > Any code that does that is already wrong if the syscall restarts with > changed ecx or if something like UML changes the syscall argument. >
No, the glibc wrapper for the system call Al was looking at used %ecx to hold a copy of the PIC pointer (normally %ebx)!
-hpa
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