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@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Alexander Potapenko <glider@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Marco Elver <elver@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Link: http://lkml.kernel.org/r/6644839d3567df61ade3c4b246a46cacbe4f9e11.1585233617.git.andreyknvl@google.com
Link: http://lkml.kernel.org/r/82625ef3ff878f0b585763cc31d09d9b08ca37d6.1584655448.git.andreyknvl@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/kernel/kcov.c b/kernel/kcov.c
index 14e7208..96dbc19 100644 (file)
--- 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);
        /*