Messages in this thread Patch in this message | | | From | Andrey Konovalov <> | Subject | [PATCH v3] kcov: properly check if we are in an interrupt | Date | Tue, 11 Oct 2016 17:05:34 +0200 |
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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.
Signed-off-by: Andrey Konovalov <andreyknvl@google.com> --- Changes in v3: - Add a description of user-visible effects of this change
kernel/kcov.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/kernel/kcov.c b/kernel/kcov.c index 8d44b3f..30e6d05 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) { -- 2.8.0.rc3.226.g39d4020
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