Messages in this thread | | | Subject | Re: [patch part-II V2 02/13] x86/entry: Mark enter_from_user_mode() notrace and NOKPROBE | From | Alexandre Chartre <> | Date | Tue, 10 Mar 2020 11:15:37 +0100 |
| |
On 3/8/20 11:24 PM, Thomas Gleixner wrote: > Both the callers in the low level ASM code and __context_tracking_exit() > which is invoked from enter_from_user_mode() via user_exit_irqoff() are > marked NOKPROBE. Allowing enter_from_user_mode() to be probed is > inconsistent at best. > > Aside of that while function tracing per se is safe the function trace > entry/exit points can be used via BPF as well which is not safe to use > before context tracking has reached CONTEXT_KERNEL and adjusted RCU. > > Mark it notrace and NOKROBE. > > Signed-off-by: Thomas Gleixner <tglx@linutronix.de> > --- > arch/x86/entry/common.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-)
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
alex.
> --- a/arch/x86/entry/common.c > +++ b/arch/x86/entry/common.c > @@ -40,11 +40,12 @@ > > #ifdef CONFIG_CONTEXT_TRACKING > /* Called on entry from user mode with IRQs off. */ > -__visible inline void enter_from_user_mode(void) > +__visible inline notrace void enter_from_user_mode(void) > { > CT_WARN_ON(ct_state() != CONTEXT_USER); > user_exit_irqoff(); > } > +NOKPROBE_SYMBOL(enter_from_user_mode); > #else > static inline void enter_from_user_mode(void) {} > #endif >
| |