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authorDmitry Vyukov <dvyukov@google.com>2017-05-08 15:56:48 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-05-08 17:15:12 -0700
commitf61e869d519c0c11a8d80a503cfdfb4897df855a (patch)
tree4befe4405314621e224b7118b42632364dc9be52 /kernel
parent8c733420bdd5a6cc2d8540fb5aa32d1fbf3cb3ff (diff)
downloadlinux-f61e869d519c0c11a8d80a503cfdfb4897df855a.tar.gz
kcov: simplify interrupt check
in_interrupt() semantics are confusing and wrong for most users as it
also returns true when bh is disabled.  Thus we open coded a proper
check for interrupts in __sanitizer_cov_trace_pc() with a lengthy
explanatory comment.

Use the new in_task() predicate instead.

Link: http://lkml.kernel.org/r/20170321091026.139655-1-dvyukov@google.com
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: James Morse <james.morse@arm.com>
Cc: Alexander Popov <alex.popov@linux.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/kcov.c9
1 files changed, 1 insertions, 8 deletions
diff --git a/kernel/kcov.c b/kernel/kcov.c
index 85e5546cd791..cd771993f96f 100644
--- a/kernel/kcov.c
+++ b/kernel/kcov.c
@@ -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;
 	mode = READ_ONCE(t->kcov_mode);
 	if (mode == KCOV_MODE_TRACE) {