The commit is pushed to "branch-rh7-3.10.0-327.36.1.vz7.20.x-ovz" and will
appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-327.36.1.vz7.20.4
------>
commit 196e6f1cd23ff1ebce902add1b5ce0112ac6d2ad
Author: Andrey Konovalov <andreyk...@google.com>
Date: Mon Nov 28 14:12:57 2016 +0400
ms/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().
Link:
http://lkml.kernel.org/r/1476115803-20712-1-git-send-email-andreyk...@google.com
Signed-off-by: Andrey Konovalov <andreyk...@google.com>
Acked-by: Dmitry Vyukov <dvyu...@google.com>
Cc: Nicolai Stange <nicsta...@gmail.com>
Cc: Andrey Ryabinin <aryabi...@virtuozzo.com>
Cc: Kees Cook <keesc...@chromium.org>
Cc: James Morse <james.mo...@arm.com>
Cc: Vegard Nossum <vegard.nos...@oracle.com>
Cc: Quentin Casasnovas <quentin.casasno...@oracle.com>
Signed-off-by: Andrew Morton <a...@linux-foundation.org>
https://jira.sw.ru/browse/PSBM-56169
Signed-off-by: Andrey Ryabinin <aryabi...@virtuozzo.com>
---
kernel/kcov.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/kernel/kcov.c b/kernel/kcov.c
index 91b00e6..83b50fe 100644
--- a/kernel/kcov.c
+++ b/kernel/kcov.c
@@ -6,6 +6,7 @@
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/mm.h>
+#include <linux/preempt_mask.h>
#include <linux/printk.h>
#include <linux/sched.h>
#include <linux/slab.h>
@@ -54,8 +55,15 @@ 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) {
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