On Tue, Mar 21, 2017 at 10:28 AM, Hillf Danton <hillf...@alibaba-inc.com> wrote: > > On March 21, 2017 5:10 PM Dmitry Vyukov wrote: >> >> @@ -60,15 +60,8 @@ void notrace __sanitizer_cov_trace_pc(void) >> /* >> * We are interested in code coverage as a function of a syscall >> inputs, >> * so we ignore code executed in interrupts. >> - * The checks for whether we are in an interrupt are open-coded, >> because >> - * 1. We can't use in_interrupt() here, since it also returns true >> - * when we are inside local_bh_disable() section. >> - * 2. We don't want to use (in_irq() | in_serving_softirq() | >> in_nmi()), >> - * since that leads to slower generated code (three separate tests, >> - * one for each of the flags). >> */ >> - if (!t || (preempt_count() & (HARDIRQ_MASK | SOFTIRQ_OFFSET >> - | NMI_MASK))) >> + if (!t || !in_task()) >> return; > > Nit: can we get the current task check cut off?
Humm... good question. I don't remember why exactly I added it. I guess something was crashing during boot. Note that this call is inserted into almost all kernel code. But probably that was before I disabled instrumentation of some early boot code for other reasons (with KCOV_INSTRUMENT := n in Makefile), because now I can boot kernel in qemu without this check. But I am still not sure about real hardware/arm/etc. Does anybody know if current can ever (including early boot) return invalid pointer?
