* [merged] kcov-properly-check-if-we-are-in-an-interrupt.patch removed from -mm tree
@ 2016-10-28 18:30 akpm
0 siblings, 0 replies; only message in thread
From: akpm @ 2016-10-28 18:30 UTC (permalink / raw)
To: andreyknvl, aryabinin, dvyukov, james.morse, keescook, nicstange,
quentin.casasnovas, vegard.nossum, mm-commits
The patch titled
Subject: kcov: properly check if we are in an interrupt
has been removed from the -mm tree. Its filename was
kcov-properly-check-if-we-are-in-an-interrupt.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Andrey Konovalov <andreyknvl@google.com>
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 <andreyknvl@google.com>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Nicolai Stange <nicstange@gmail.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: James Morse <james.morse@arm.com>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
kernel/kcov.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff -puN kernel/kcov.c~kcov-properly-check-if-we-are-in-an-interrupt kernel/kcov.c
--- a/kernel/kcov.c~kcov-properly-check-if-we-are-in-an-interrupt
+++ a/kernel/kcov.c
@@ -53,8 +53,15 @@ void notrace __sanitizer_cov_trace_pc(vo
/*
* 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) {
_
Patches currently in -mm which might be from andreyknvl@google.com are
^ permalink raw reply [flat|nested] only message in thread
only message in thread, other threads:[~2016-10-28 18:30 UTC | newest]
Thread overview: (only message) (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-10-28 18:30 [merged] kcov-properly-check-if-we-are-in-an-interrupt.patch removed from -mm tree akpm
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.