From b274c0bb394c6a69ac12feac7c2db81f5aff5a55 Mon Sep 17 00:00:00 2001 From: Andrey Konovalov Date: Thu, 27 Oct 2016 17:46:21 -0700 Subject: kcov: properly check if we are in an interrupt in_interrupt() returns a nonzero value when we are either in an interrupt or have bh disabled via local_bh_disable(). Since we are interested in only ignoring coverage from actual interrupts, do a proper check instead of just calling in_interrupt(). As a result of this change, kcov will start to collect coverage from within local_bh_disable()/local_bh_enable() sections. Link: http://lkml.kernel.org/r/1476115803-20712-1-git-send-email-andreyknvl@google.com Signed-off-by: Andrey Konovalov Acked-by: Dmitry Vyukov Cc: Nicolai Stange Cc: Andrey Ryabinin Cc: Kees Cook Cc: James Morse Cc: Vegard Nossum Cc: Quentin Casasnovas Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/kcov.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/kcov.c b/kernel/kcov.c index 8d44b3fea9d0..30e6d05aa5a9 100644 --- a/kernel/kcov.c +++ b/kernel/kcov.c @@ -53,8 +53,15 @@ 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 || in_interrupt()) + if (!t || (preempt_count() & (HARDIRQ_MASK | SOFTIRQ_OFFSET + | NMI_MASK))) return; mode = READ_ONCE(t->kcov_mode); if (mode == KCOV_MODE_TRACE) { -- cgit v1.2.3