Messages in this thread | | | Date | Tue, 3 Oct 2017 19:11:00 +0200 | From | Ingo Molnar <> | Subject | Re: [BUGFIX PATCH] kprobes/x86: Remove IRQ disabling from jprobe handlers |
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* Masami Hiramatsu <mhiramat@kernel.org> wrote:
> On Tue, 3 Oct 2017 11:33:44 +0200 > Ingo Molnar <mingo@kernel.org> wrote: > > > > > * Masami Hiramatsu <mhiramat@kernel.org> wrote: > > > > > Jprobe actually doesn't need to disable IRQs while calling > > > handlers, because Documentation/kprobes.txt says: > > > > > > ----- > > > Probe handlers are run with preemption disabled. Depending on the > > > architecture and optimization state, handlers may also run with > > > interrupts disabled (e.g., kretprobe handlers and optimized kprobe > > > handlers run without interrupt disabled on x86/x86-64). > > > ----- > > > > > > So let's remove IRQ disabling from jprobes too. > > > > > > Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> > > > --- > > > arch/x86/kernel/kprobes/core.c | 2 -- > > > 1 file changed, 2 deletions(-) > > > > > > diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c > > > index b48e0efd668e..bd36f3c33cd0 100644 > > > --- a/arch/x86/kernel/kprobes/core.c > > > +++ b/arch/x86/kernel/kprobes/core.c > > > @@ -1099,8 +1099,6 @@ int setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs) > > > * raw stack chunk with redzones: > > > */ > > > __memcpy(kcb->jprobes_stack, (kprobe_opcode_t *)addr, MIN_STACK_SIZE(addr)); > > > - regs->flags &= ~X86_EFLAGS_IF; > > > - trace_hardirqs_off(); > > > regs->ip = (unsigned long)(jp->entry); > > > > > > /* > > > > Could you please also do a patch that disables jprobes permanently, in preparation > > of eventually removing them later? > > Would you mean introducing CONFIG_JPROBE_API and cut APIs out, > or just adding "__deprecated" for each API?
No, I'd suggest removing in-kernel uses and disabling jprobes in the Kconfig altogether, but without removing the code and its integration for the time being.
Thanks,
Ingo
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