arch/x86/kernel/vsyscall_64.c: overeager NOP of syscalls

Arne Georg Gleditsch
2008-02-20T14:26:32Z

Hi,

I'm looking at 2.6.25-rc2. vsyscall_sysctl_change contains code to NOP
out the actual system call instructions of the vsyscall page when
vsyscall64 is enabled. This seems to interact badly with the fallback
code in do_vgettimeofday which tries to call gettimeofday if the
configured clock source does not support vread. (In effect,
gettimeofday() becomes a nop and time() always returns 0. Not very
useful.)

Is there a good reason to keep this? Aren't the instructions in
question avoided (or invoked) according to the vsyscall64 flag by the
surrounding logic anyway?

--
Arne.