Re: [PATCH v4 5/5] tracing: convert sys_enter/exit to faultable tracepoints

[Mathieu Desnoyers]

On 2023-11-20 16:46, Peter Zijlstra wrote:
> On Mon, Nov 20, 2023 at 03:54:18PM -0500, Mathieu Desnoyers wrote:
>
> > diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
> > index de753403cdaf..718a0723a0bc 100644
> > --- a/kernel/trace/trace_syscalls.c
> > +++ b/kernel/trace/trace_syscalls.c
> > @@ -299,27 +299,33 @@ static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id)
> >   	int syscall_nr;
> >   	int size;
> >   
> > +	/*
> > +	 * Probe called with preemption enabled (may_fault), but ring buffer and
> > +	 * per-cpu data require preemption to be disabled.
> > +	 */
> > +	preempt_disable_notrace();
>
> 	guard(preempt_notrace)();
>
> and ditch all the goto crap.

[ more guard stuff ]

Sure, will do, thanks!

Mathieu

--
Mathieu Desnoyers
EfficiOS Inc.
https://www.efficios.com