Re: [RFC][PATCH] kprobes: Remove kprobe::fault_handler
On Wed, Feb 10, 2021 at 5:57 AM Peter Zijlstra wrote: > > > Somewhat related.. I had this pending. > > --- > Subject: kprobes: Remove kprobe::fault_handler > From: Peter Zijlstra > Date: Tue Feb 2 10:43:41 CET 2021 > > The reason for kprobe::fault_handler(), as given by their comment: > > * We come here because instructions in the pre/post > * handler caused the page_fault, this could happen > * if handler tries to access user space by > * copy_from_user(), get_user() etc. Let the > * user-specified handler try to fix it first. > > If just plain bad. Those other handlers are ran from non-preemptible > context and had better use _nofault() functions. Also, there is no > upstream usage of this. No objections from me. Since Masami mentioned that systemtap used that you probably want to give them a courtesy heads-up that it's going away. Though looking at systemtap source code I couldn't find any reference to it. So it's likely a nop for them anyway.
Re: [RFC][PATCH] kprobes: Remove kprobe::fault_handler
On Wed, Feb 10, 2021 at 02:57:03PM +0100, Peter Zijlstra wrote: > > Somewhat related.. I had this pending. > > --- > Subject: kprobes: Remove kprobe::fault_handler > From: Peter Zijlstra > Date: Tue Feb 2 10:43:41 CET 2021 > > The reason for kprobe::fault_handler(), as given by their comment: > > * We come here because instructions in the pre/post > * handler caused the page_fault, this could happen > * if handler tries to access user space by > * copy_from_user(), get_user() etc. Let the > * user-specified handler try to fix it first. > > If just plain bad. Those other handlers are ran from non-preemptible > context and had better use _nofault() functions. Also, there is no > upstream usage of this. > > Signed-off-by: Peter Zijlstra (Intel) Looks good, Reviewed-by: Christoph Hellwig
