| From | Matthew Maurer <> | Subject | Re: [PATCH v5 4/9] x86-64: Remove kernel.vsyscall64 sysctl | Date | Mon, 5 Dec 2011 18:27:09 +0000 (UTC) |
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Andy Lutomirski <luto <at> MIT.EDU> writes:
> > It's unnecessary overhead in code that's supposed to be highly > optimized. Removing it allows us to remove one of the two syscall > instructions in the vsyscall page. > > The only sensible use for it is for UML users, and it doesn't fully > address inconsistent vsyscall results on UML. The real fix for UML > is to stop using vsyscalls entirely.
UML is not the only use case for this. Anybody who wants to be able to trace _all_ system calls (for debugging, ptrace-based sandboxing, or a number of other purposes) needs this.
We either need this back, or need another way to make it possible to trace these system calls.
Apologies for the late reply, I didn't notice this change until it got into my distribution's kernel.
--Matthew Maurer
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