linux-kernel - [PATCH v4 3/7] kcov: move t->kcov assignments into kcov

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Message-Id: <6644839d3567df61ade3c4b246a46cacbe4f9e11.1585233617.git.andreyknvl@google.com>
Date:   Thu, 26 Mar 2020 15:44:02 +0100
From:   Andrey Konovalov <andreyknvl@...gle.com>
To:     Dmitry Vyukov <dvyukov@...gle.com>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Alan Stern <stern@...land.harvard.edu>,
        Andrew Morton <akpm@...ux-foundation.org>,
        linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
        Alexander Potapenko <glider@...gle.com>,
        Marco Elver <elver@...gle.com>,
        Andrey Konovalov <andreyknvl@...gle.com>
Subject: [PATCH v4 3/7] kcov: move t->kcov assignments into kcov_start/stop

Every time kcov_start/stop() is called, t->kcov is also assigned, so
move the assignment into the functions.

Signed-off-by: Andrey Konovalov <andreyknvl@...gle.com>
---
 kernel/kcov.c | 16 +++++++---------
 1 file changed, 7 insertions(+), 9 deletions(-)

diff --git a/kernel/kcov.c b/kernel/kcov.c
index cc5900ac2467..888d0a236b04 100644
--- a/kernel/kcov.c
+++ b/kernel/kcov.c
@@ -309,10 +309,12 @@ void notrace __sanitizer_cov_trace_switch(u64 val, u64 *cases)
 EXPORT_SYMBOL(__sanitizer_cov_trace_switch);
 #endif /* ifdef CONFIG_KCOV_ENABLE_COMPARISONS */
 
-static void kcov_start(struct task_struct *t, unsigned int size,
-			void *area, enum kcov_mode mode, int sequence)
+static void kcov_start(struct task_struct *t, struct kcov *kcov,
+			unsigned int size, void *area, enum kcov_mode mode,
+			int sequence)
 {
 	kcov_debug("t = %px, size = %u, area = %px\n", t, size, area);
+	t->kcov = kcov;
 	/* Cache in task struct for performance. */
 	t->kcov_size = size;
 	t->kcov_area = area;
@@ -326,6 +328,7 @@ static void kcov_stop(struct task_struct *t)
 {
 	WRITE_ONCE(t->kcov_mode, KCOV_MODE_DISABLED);
 	barrier();
+	t->kcov = NULL;
 	t->kcov_size = 0;
 	t->kcov_area = NULL;
 }
@@ -333,7 +336,6 @@ static void kcov_stop(struct task_struct *t)
 static void kcov_task_reset(struct task_struct *t)
 {
 	kcov_stop(t);
-	t->kcov = NULL;
 	t->kcov_sequence = 0;
 	t->kcov_handle = 0;
 }
@@ -584,9 +586,8 @@ static int kcov_ioctl_locked(struct kcov *kcov, unsigned int cmd,
 			return mode;
 		kcov_fault_in_area(kcov);
 		kcov->mode = mode;
-		kcov_start(t, kcov->size, kcov->area, kcov->mode,
+		kcov_start(t, kcov, kcov->size, kcov->area, kcov->mode,
 				kcov->sequence);
-		t->kcov = kcov;
 		kcov->t = t;
 		/* Put either in kcov_task_exit() or in KCOV_DISABLE. */
 		kcov_get(kcov);
@@ -778,7 +779,6 @@ void kcov_remote_start(u64 handle)
 	kcov = remote->kcov;
 	/* Put in kcov_remote_stop(). */
 	kcov_get(kcov);
-	t->kcov = kcov;
 	/*
 	 * Read kcov fields before unlock to prevent races with
 	 * KCOV_DISABLE / kcov_remote_reset().
@@ -792,7 +792,6 @@ void kcov_remote_start(u64 handle)
 	if (!area) {
 		area = vmalloc(size * sizeof(unsigned long));
 		if (!area) {
-			t->kcov = NULL;
 			kcov_put(kcov);
 			return;
 		}
@@ -800,7 +799,7 @@ void kcov_remote_start(u64 handle)
 	/* Reset coverage size. */
 	*(u64 *)area = 0;
 
-	kcov_start(t, size, area, mode, sequence);
+	kcov_start(t, kcov, size, area, mode, sequence);
 
 }
 EXPORT_SYMBOL(kcov_remote_start);
@@ -873,7 +872,6 @@ void kcov_remote_stop(void)
 		return;
 
 	kcov_stop(t);
-	t->kcov = NULL;
 
 	spin_lock(&kcov->lock);
 	/*
-- 
2.26.0.rc2.310.g2932bb562d-goog