[PATCH] tracing/syscalls: ignore numbers outside NR_syscalls' range

[Russell King - ARM Linux]

On Thu, Oct 30, 2014 at 01:26:06AM -0700, Christoph Hellwig wrote:
> On Wed, Oct 29, 2014 at 11:06:58PM +0100, Rabin Vincent wrote:
> > ARM has some private syscalls (for example, set_tls(2)) which lie
> > outside the range of NR_syscalls.  If any of these are called while
> > syscall tracing is being performed, out-of-bounds array access will
> > occur in the ftrace and perf sys_{enter,exit} handlers.
> 
> While this patch looks like good caution, having syscalls outside of
> NR_syscalls seems like a receipe for a disaster.  Can you try to fix
> that issue as ell, please?

No.  We've had them since the inception of Linux on ARM.  They predate
this tracing crap by more than a decade.  We're not changing them
because that would be a massive user API breakage.

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