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From: Andrey Konovalov <andreyknvl@google.com>
To: Dmitry Vyukov <dvyukov@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Alan Stern <stern@rowland.harvard.edu>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
	Alexander Potapenko <glider@google.com>,
	Marco Elver <elver@google.com>,
	Andrey Konovalov <andreyknvl@gmail.com>,
	Andrey Konovalov <andreyknvl@google.com>
Subject: [PATCH v3 3/7] kcov: move t->kcov assignments into kcov_start/stop
Date: Thu, 19 Mar 2020 23:11:37 +0100	[thread overview]
Message-ID: <82625ef3ff878f0b585763cc31d09d9b08ca37d6.1584655448.git.andreyknvl@google.com> (raw)
In-Reply-To: <cover.1584655448.git.andreyknvl@google.com>

From: Andrey Konovalov <andreyknvl@gmail.com>

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@google.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);
 	/*
-- 
2.25.1.696.g5e7596f4ac-goog


  parent reply	other threads:[~2020-03-19 22:12 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-19 22:11 [PATCH v3 0/7] kcov: collect coverage from usb soft interrupts Andrey Konovalov
2020-03-17 14:54 ` [PATCH USB] usb: raw_gadget: fix compilation warnings in uapi headers Andrey Konovalov
2020-03-19 22:11   ` Andrey Konovalov
2020-03-19 22:13   ` Andrey Konovalov
2020-03-19 22:11 ` [PATCH v3 1/7] kcov: cleanup debug messages Andrey Konovalov
2020-03-19 22:11 ` [PATCH v3 2/7] kcov: fix potential use-after-free in kcov_remote_start Andrey Konovalov
2020-03-19 22:11 ` Andrey Konovalov [this message]
2020-03-19 22:11 ` [PATCH v3 4/7] kcov: move t->kcov_sequence assignment Andrey Konovalov
2020-03-19 22:11 ` [PATCH v3 5/7] kcov: use t->kcov_mode as enabled indicator Andrey Konovalov
2020-03-19 22:11 ` [PATCH v3 6/7] kcov: collect coverage from interrupts Andrey Konovalov
2020-03-19 22:11 ` [PATCH v3 7/7] usb: core: kcov: collect coverage from usb complete callback Andrey Konovalov

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